Reprinted from the September 2004 edition of the Mössbauer Spectroscopy Newsletter, published as part of Volume 27, Issue 7 of the Mössbauer Effect Reference and Data Journal

Mössbauer Spectroscopy in Latin America

This issue of the Newsletter features reports from 23 active Mössbauer research laboratories in Latin America. The reports appear in descending order of most active Latin American institutions by country, in alphabetical order, based on the records of the Mössbauer Effect Data Center.

Departamento de Física
Universidad Nacional de La Plata
La Plata, Argentina

Names and Titles of Researchers Dr. Roberto C. Mercader – Director Dr. Judith Desimoni – Vice-Director Dr. Sergio G. Marchetti – Catalysis Group Leader Dr. Silvana J. Stewart – Scientist Dr. Sonia M. Cotes – Scientist Dr. Edgardo D. Cabanillas – Scientist Dr. Karina F. Laneri – Scientist Lic. Javier Martínez – Ph.D. Student M.Sc. Luis D. Junciel – Design and Support Engineer Mr. Martín Mizrahi – Student Mr. Alejandro Durán – Student Mr. Mauricio Sturla – Student Mr. Flavio Sives – Technician

L-R: Sonia M. Cotes, Roberto C. Mercader, and Javier Martínez

Areas of Research

Dr. Mercader’s group at the Departamento de Física at the Universidad Nacional de La Plata is currently working on the following topics:

• Systems of magnetic nanoparticles: Synthesis and experimental research of parameters that govern the magnetic ordering. Investigation of spin-glass-like behaviors and of magnetic anisotropy in nanostructured systems of transition metal oxides.
  
  

• Iron-based alloys: Distribution of N and C atoms in fcc gamma-Fe; fcc, bct and hcp phases stability in Fe-Mn and Fe-Mn-Si alloys; nucleation and growth kinetics of transformed phases in cast irons.
  
  

• Supported catalysts: Synthesis of Fisher-Tropsch and ethanol hydro-treatment massic or supported catalysts: metallic or iron oxide particles supported on amorphous, microporous, and mesoporous solids.
  
  

• Iron silicides: Synthesis and characterization of pure and doped FeSi₂, determination of thermoelectric properties.
  
  

• Soils, mineralogy, geology and archeology: Loess-paleosols sequences in Argentine sediments. Physical and chemical properties of soils. Ancient ceramics from Argentine archeological sites. Characterization of magnetic impurities in minerals.

Current national and international collaborations include:

• Instituto de Física de Líquidos y Sistemas Biológicos, La Plata, Argentina: Dr. Eitel L. Peltzer y Blancá, Dr. Guillermo Zarragoicoechea

• Laboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológica, La Plata, Argentina: Eng. Ricardo W. Gregorutti, Dr. Juan C. Bidegain

• Instituto de Geomorfología y Suelos, La Plata, Argentina: Dr. Perla A. Imbellone

• Centro de Tecnología de Recursos Minerales y Cerámica, La Plata, Argentina: Dr. Rosa Torres Sánchez, Dr. Esteban F. Aglietti

• Instituto Balseiro, Centro Atómico Bariloche, Argentina: Dr. Armando Fernández Guillermet, Dr. Manuel Tovar, Dr. Roberto Zysler

• Facultad de Ingeniería, Universidad de Buenos Aires, Argentina: Dr. Stella Duhalde, Dr. Silvia Jacobo

• Department of Subatomic and Radiation Physics, Ghent University, Belgium: Prof. Robert E. Vandenberghe

• Laboratoire de Physique de L’Etat Condensé, Université du Maine, Le Mans, France: Dr. Jean-Marc Grenèche

• Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil: Prof. Rosa B. Scorzelli

Departamento de Física
Universidad Nacional de La Plata
La Plata, Argentina

From left to right and up to down: Christian Cuadrado Laborde, Francisco Sánchez, Marcela Fernández van Raap, Fabiana Cabrera, Luis Mendoza Zélis, Marisa Bab, Pedro Mendoza Zélis, Claudia Rodríguez Torres, Laura Damonte

Names and Titles of Researchers

The overall group is in fact composed of two associated and strongly interacting groups.

Group Leaders:

Dr. Luis Mendoza Zélis
Dr. Francisco H. Sánchez

Group Persons:

Dr. Laura Damonte – Scientist
Dr. Marcela Fernández van Raap – Scientist
Dr. Fabiana Cabrera – Junior Scientist
Dr. Marcos Meyer – Junior Scientist
Dr. Claudia Rodríguez Torres – Junior Scientist
Dr. Fabio Saccone – Post Doctoral Researcher (Part Time)
Lic. Lorena Baum - Graduate Student
Eng. Christian Cuadrado Laborde – Graduate Student
Lic. Pedro Mendoza Zélis – Graduate Student
Lic. Gustavo Pasquevich – Graduate Student

Areas of Research

• Technique Development (FHS) – Development and formalization of Mössbauer thermal scans and isothermal experiments as a fast analytical quantitative tool for the study of phase transitions, metastable materials evolution, reaction kinetics, and relaxation processes. Application to the study of hyperfine field temperature dependence and frequency dependence of hysteresis processes of new soft magnetic materials.
  
  

• New Magnetic Materials with Technological Applications (FHS) –
  
  

• Magnetic nanocomposites aerogel/magnetic phase (transition metal, iron oxide, etc.): ultralight, ultrainsulator, transparent, magnetic materials with novel properties. Distribution of magnetic particles among aerogel nanopores, interaction among particles and magnetic dynamics. Magnetoelastic effects in metal/amorphous ribbon/metal micrometer trilayers with temperature-force sensor applications. Application of Mössbauer effect spectroscopy to the study of magnetic stress-induced anisotropy distribution in melt-spun metallic glasses.
  
  

• Magnetic and structural properties of hard magnetic composite materials (Nd-Fe-Al base and related) produced by melt-spinning.
  
  

• Thermal evolution, structural, and magnetic properties of soft magnetic materials prepared by mechanosynthesis/melt-spinning and subsequent nanocrystallization.
  
  

• Mechanosynthesis of diluted magnetic semiconductor precursors.
  
  

• Nanocrystalline and Mechanically Alloyed Materials (LMZ): These materials, with grains and domains of a few nm, are well suited for the local information provided by MS. The group currently focuses their research on the following systems:
  
  

• Nanocrystalline nitrides and hydrides made by mechanically assisted gas solid reactions. Applications to hydrogen storage materials are in course. The role of Fe based catalysts will be studied by MS.
  
  

• Disordered AlFeX solid solutions. with complex magnetic structures. AlCuFe alloys are presently under study.
  
  

• Iron/ceramic dispersions made by self-sustained displacement reactions, such as Fe₂O₃+Al⇒Fe+Al₂O₃. A thesis on the subject is being concluded.

Other techniques include XRD, SAXS, magnetometry, susceptometry, differential calorimetry, thermomagnetometry, positron anihilation, etc. The group’s equipment includes three Mössbauer spectrometers, with facilities for low and high temperatures.

The combined group has published more than 170 papers, more than 95 of which concern Mössbauer spectroscopy. During the last six years, members of the group have defended five Ph.D. theses concerning Mössbauer effect spectroscopy, and four additional Ph.D. theses are currently underway. The group’s present scientific international and national collaborators include:

• IFW, Dresden, Germany (J. Eckert)

• ICMM-CSIC, Madrid, España (M. Vázquez Villalabeitia)

• UAB, Barcelona, España (M. T. Mora, N. Clavaguera)

• ICMB-CSIC, Barcelona, España (A. Roig)

• UNICAMP-LNLS, Campinas, Brasil (I. Torriani, M. Knobel, L. Socolovsky)

• UFES-Vitoria, Brasil (C. Larica, E. Passamani)

• FAMAF, Córdoba, Argentina (S. Urreta)

• FI-UBA, Buenos Aires, Argentina (H. Sirkin, S. Duhalde)

• Dipartimento Ing. Mecánica, Universidad de Padua, Italia (G. Principi)

Mössbauer Spectroscopy Laboratorio
Departmento de Física
Comisión Nacional de Energía Atómica
Buenos Aires, Argentina

Names and Titles of Researchers Celia Saragovi – Director Cinthia Ramos – Ph.D. Student Victor Alexis Bettachini – Ph.D. Student Patricia Bozzano – Collaborator Scientist Josefina Arpe – Student Diego Daroca – Student

Celia Saragovi

History and Areas of Research

At the end of 1962, Dr. Carlos Abeledo suggested that a Mössbauer spectroscopy group be formed and that the equipment be built in the local workshop as much as possible. That group was formed by Carlos Abeledo, Juan Peyre, Eduardo Ansaldo, and Enrique Frank. During 1963-1964, the laboratory was developed in the Department of Physics, Facultad de Ciencias Exactas, University of Buenos Aires. In September 1964, the first report on Mössbauer spectrocopy in Argentina was presented at the national meeting of the Argentinian Physical Society (AFA). The first international publication was "Mössbauer Effect on iron tri dithiocarbonates" by E. Frank and C. Abeledo in Inorg. Chem. 5, 1453 (1966). E. Frank went on to work with D. St.P. Bumbury at Manchester University, England, and returned to the country in February of 1969.

He began to work at the Argentine Atomic Energy Commission (CNEA), where he founded the Laboratory of Mössbauer Spectroscopy. During 1970, he was jointed by Felisa Labenski and Celia Saragovi. Some of the lab's first equipment was bought with funds provided by CNEA; an Elscint spectrometer Serie 2, an Elron furnace, a variable temperature cryostat, a temperature controller, and spare parts. The CONICET provided grants to complete the installation of this early laboratory. This laboratory increased the researchers' scientific activity, but in recent years has suffered from a shortage of funds and students, both due to Argentina's economic situation. Since 1988, Celia Saragovi has been in charge of this laboratory, and the present location is at the Centro Atómico Constituyentes, CNEA, Buenos Aires.

In the last decade, the laboratory has produced approximately 45 international papers, was a co-organizer of LACAME '92 and FCM 2004 (in the Frontier of the Condensed Matter: Magnetism, Magnetic Materials and their Applications), gave approximately 68 presentations at national and international conferences, has overseen the training of post-doctoral researchers and doctoral and degree students from both Argentina and abroad, and has provided courses in Argentina and abroad. Collaborations have included D. St.P. Bumbury (University of Manchester), J. M. Friedt (private industry), J. M. Greneche (University of Le Mans), C. Barrero Meneses (University of Antiochia), H. Morrás (Instituto Nacional de Tecnología Agropecuaria), S. Acebal and E. Rueda (Department of Chemistry, Universidad del Sur), C. Fainstein and R. Zysler (Centro Atómico Bariloche, CNEA), E. Rueda (University of Buenos Aires), and D. Arias, M. Granovsky, and G. Soler-Illia (Centro Atómico Constituyentes, CNEA).

Continuing the activities of past years, the laboratory is currently engaged in three research fields:

• Magnetic properties of nanoparticles, particularly the effects of inter- and intra-particle interactions in antiferromagnetic nanohematites and in amorphous ferromagnetic NiFeB nanoparticles, and structural and magnetic effects of cation substitution in Fe oxides.
  
  

• Fundamental studies of soil-related compounds, such as Fe oxides and oxyhydroxides, particularly in poorly-developed soils, including comparation with highly developed soils, and all soils from Argentina. The area includes contribution to studies about the genesis of soils from NE Argentina.
  
  

• Properties of Zr-based metallic systems: precise analysis of phases present in the Zr-Fe-Nb and Zr-Fe-Cr systems, and structural changes around the Fe ions and oxidation dynamics under Nb or O introduction.

Magnetic Resonance Laboratory
Instituto Balseiro
Centro Atomico Bariloche
San Carlos de Bariloche, Argentina
http://www.cab.cnea.gov.ar/cab/invbasica/Resonancia/

Name of Researcher

Dr. Roberto D. Zysler

History and Areas of Research

The Magnetic Resonance Laboratory of the "Centro Atómico Bariloche" created a Mössbauer facility about two years ago; the laboratory was originally created in the early 1960s as a magnetic resonance laboratory. The first works were specifically in magnetic resonance in condensed matter and progressively the laboratory had an evolution to magnetic properties in condensed matter. Now, the laboratory works mainly in magnetic and magneto-transport properties in perovskites, in magnetic nanostructures, and in EPR spectroscopy in solids.

The lab's contact with Mössbauer spectroscopy came a long time before the acquisition of the spectrometer; its first works including Mössbauer results were during the second half of 1980 in cooperation with the Mössbauer laboratory of CNEA at Buenos Aires and the Mössbauer laboratory at La Plata University (both from Argentina). These cooperations still continue.

The lab's Mössbauer spectrometer consists of an ASA system for ⁵⁷Fe isotope working from 4K to 600K (with a liquid He cryostat and a furnace in vacuum). For magnetic and magnetic resonance measurements the lab has magnetometers (VSM, Faraday balance, and SQUID), AC susceptometer, and EPR spectrometers.

For more information regarding the laboratory, research lines, and publications, please see the Web site: <http://www.cab.cnea.gov.ar/cab/invbasica/Resonancia/>.

Centro Brasileiro de Pesquisas Físicas – CBPF
(Brazilian Center for Physical Research)
Rio de Janeiro, Brazil

Names and Titles of Researchers

Experimentalists:

Elisa Baggio-Saitovitch, Ph.D. – Full Researcher
Rosa Bernstein Scorzelli, Ph.D. – Full Researcher
Izabel de Souza Azevedo, Ph.D. – Associate Researcher
Magda Fontes, Ph.D. – Associate Researcher
Julio Larrea – Post-Doctoral Researcher
Ada López – Post-Doctoral Researcher
Valberto Pedruzzi Nascimento – Ph.D. Student
Pablo Munayco – Ph.D. Student
William Edgardo Alayo Rodríguez – Ph.D. Student
Urbano Miguel Tafur Tanta – M.Sc. Student
Alexander Caytuero – M.Sc. Student
Alexandre Mello – Engineer
Henrique Duarte – Technician

Theoreticians:

Diana Guensburguer – Full Researcher
Joice Terra – Associate Researcher
Donald Ellis – Visiting Researcher

History and Areas of Research

The group at the CBPF was initiated by Prof. Jacques A. Danon in the early 1960s. Currently, the group researches the local physical properties and magnetism of ⁵⁷Fe, ¹¹⁹Sn, and ¹⁵¹Eu in:

• Heavy fermions and superconducting compounds

• Nanostructured materials prepared by sputtering, mechanical alloying, and thermal evaporation

• Nanomagnetism of Fe nanoparticles

• Intermetallic and oxides compounds

• Meteorites, soils, and minerals

• Archaeometry

• Catalysis and rust converters

• Thin film and multilayers

• Biomaterials for drug delivery

The group has published more than 135 research papers on Mössbauer spectroscopy within the past ten years.

The lab at the CBPF has available six Mössbauer spectrometers, a CEMS spectrometer, a liquid He-superconducting magnet-variable temperature Oxford Cryostat (10 Tesla, 1.5-300K), an Oxford Cryostat (liquid helium-variable temperature 2-300 K), an APD close cycled cryostat (12-300K), a high temperature in situ Mössbauer furnace (300 K-1000 K), two cryostats for thin film preparation with in situ Mössbauer spectroscopy and CEMS.

The group has other facilities for structural, transport, and magnetization measurements and production of liquid He and liquid N₂.

Recently new facilities for transport measurements under pressure down to 40 mK, have been installed, mainly dedicated to heavy fermion studies.

In Rio de Janeiro, the group has collaborators working in metallurgy, chemistry, geology, catalysis, corrosion, and biology (for biomaterials) at the Universidade Federal do Rio de Janeiro and research institutes.

Collaborations with others in Brazil include C. Larica and E. Passamani (Vitória), L. Nagamine and Livio Amaral (Porto Alegre), Jose Domingos Fabris (Belo Horizonte), and others. Internationally, the group collaborates with Hans Micklitz and Mohsen Abd-Elmeguid (Köln, Germany), F. J. Litterst (Braunschweig, Germany), M. Ghafari (Darmstadt, Germany), Marek Przybylski (Cracow, Poland), Joseph Goldstein (USA), Gerard Poupeau (France), Noel Nava (Mexico), Victor Peña Rodrigues and Angel Bustamante (Perú), and Roberto Mercader and Edgardo Cabanillas, Silvana Stewart and M. E. Varela (Argentina).

In 1988, the group at the CBPF started organizing a series of conferences, of which LACAME was the first, followed by ICAME'97. The organization of M2S-HTSC in May 2003 was under the responsibility of Elisa Baggio Saitovitch, and Rosa Bernstein Scorzelli together with Izabel Azevedo organized the Meteoritical Society Meeting in August 2004. Both conferences were organized for the first time in South America.

Mössbauer Group
Departamento de Química
Universidade Federal de Minas Gerais
Belo Horizonte, Minas Gerais, Brazil
www.qui.ufmg.br/~Moss

Names and Titles of Researchers Staff Researchers: José Domingos Fabris – Leader Rochel Monteiro Lago Wagner da Nova Mussel Visiting Researchers: Maria de Fátima Fontes Lelis Luis Carlos Alves Oliveira Graduate Students: Alexandre dos Santos Anastácio Regina Celi de Carvalho Costa Paulo Rogério Costa Couceiro Múcio do Amaral Figueiredo Patrícia Gonçalves Pinheiro Fabiana Rodrigues Ribeiro Fernando Dias da Silva Márcio César Pereira Undergraduate Students: Thiago Alexandre Borges Flávia dos Santos Coelho Ana Lúcia Lopes Isabella Vidal Pinto Leonardo Vasconcellos Rangel

History and Areas of Research

The Mössbauer laboratory at the Department of Chemistry of the Federal University of Minas Gerais (UFMG) was organized in the mid-1980s by the late Professor Milton Francisco de Jesus Filho (1947–1996) [see the note contained in the Mössbauer Spectroscopy Newsletter, Mössbauer Effect Reference and Data Journal, 19(3):60, March 1996]. It is one of the four Mössbauer laboratories in the state of Minas Gerais (three in the city of Belo Horizonte), and currently hosts an 18-person research team comprised of seven D.Sc., one M.Sc., and five undergraduate students and three staff and two visiting researchers.

The main research interest is concerned with the identification and characterization and use of iron-bearing minerals from geomaterials. The on-going projects include (i) the characterization of magnetic minerals from soils developing on mafic and some volcanic materials; (ii) the occurrence and distribution of iron in the mineral structure of oxides and phyllosilicates from commercially exploited kaolin deposits; (iii) iron-sulfides related to acid drainage in gold, coal, and copper mining areas; (iv) chemical, structural and magnetic characterization and catalytic behavior of synthetic and natural iron-rich spinels; (v) iron-redox systems in clay minerals; and (vi) studies of some archaeological samples of Marajora ceramics from northern Brazil.

Further information about the laboratory can be found at <www.qui.ufmg.br/~Moss>.

Laboratório de Materiais Magnéticos
Instituto de Física
Universidade de São Paulo
São Paulo, Brazil
http://macbeth.if.usp.br/~goya/mosslab0.htm

Names and Titles of Researchers Hercilio R. Rechenberg – Laboratory Chief Carmen S. M. Partiti – Assistant Professor Gerardo F. Goya – Assistant Professor Ana Lúcia Brandl – Post-Doctoral Fellow Enio Lima Jr. – Post-Doctoral Fellow Rafael Alejandro Cajacuri Merino – Student Waldir Leles Martins Filho – Student Amanda D. Arelaro – Student

Gerardo F. Goya

Areas of Research

The main research lines at the Magnetic Materials Laboratory (LMM) involve the manufacture of a magnetic material, usually for some practical use, as well as its magnetic and structural characterization. Magnetic measures in the broad sense (magnetization, Mössbauer spectroscopy, magneto-optical, and magnetoresistance) are compared with microscopic theories to understand the macroscopic behavior of these materials. Thus, professors and students carry through research in magnetism and the results of this research are published in specialized magazines. The manufacture of materials and its microstructural characterization involve activities related to materials science. The practical knowledge acquired on many occasions has resulted in technology transfer to the productive sector. Many Ph.D. and M.Sc. degrees have been awarded during recent years.

The Mössbauer Laboratory is a part of the LMM group and, in addition to the above activities, has its specific research lines focused on local properties of materials, phase characterization, nanomagnetism, and Mössbauer instrumentation. Systems and properties investigated include:

• Exchange bias in multilayers FM/AFM (A. D. Santos)
  
  

• Pseudobinary alloys and hidrides (H. R. Rechenberg)
  
  

• Ultrafine Magnetic Particles (H. R. Rechenberg and G. F. Goya). The study of the structural and magnetic properties of nanostructured materials involves mainly ferrofluids constituted of nanoparticles with internal structure of spinel type, generated from watery solutions of transition metals, including determination of the average diameter of nanoparticles and its relation to the effect of superficial disorder in the arrangement of spins and study of the effect of the redistribution of ions in the interstitial small farms of the spinel structure, and in the surface of particles.
  
  

• Magnetite Nanoparticles for Biomedical Applications (G. F. Goya). For biomedical applications the particles are functionalized with organic covers, and used mainly as MRI contrast agents in clinical procedures. The group is currently doing research on intrinsic particle properties for design of new magnetite-based ferrofluids for clinical applications.
  
  

• Magnetite Nanoparticles and Films Grown by Chemical Vapor Deposition (G. F. Goya). The group is carrying on a systematic study on the structural and magnetic properties of novel nanostructured materials, synthesized from a molecular-based approach using single source precursors. Based on the strict control of molecular growth and aggregation during synthesis, they aim to characterize the magnetic response of monodispersed, non-interacting magnetic particles from the molecular range to nanometric dimensions. The group investigates surface effects and spin disorder, and its connection with magnetic moment enhancement. The collective behavior through dipolar interactions will be investigated by means of magnetic dynamic techniques such as a.c. magnetic susceptibility and Mössbauer spectroscopy at different temperatures, and applied fields. For systems like thin films, they are investigating the effects of sample microstructure on the magnetic and transport properties. The group also measures the effects of structural features such as grain boundaries, oxygen vacancies, and lattice dislocations on the magnetic properties of fully stoichiometric Fe₃O₄ thin films grown by CVD technique, and the consequent effects on the magnetoresistive response of the system. Specifically, the role of antiphase boundaries on magnetotransport is under study.
  
  

• Magnetically Hard Magnets Based on Intermetallic Compounds (Rare-Earths) (H. R. Rechenberg)
  
  

• Mechanosynthesized Magnetic Materials (mainly spinels, ternary sulphides and Fe-based ceramics) (G. F. Goya)
  
  

• Environmental magnetism (C. S. M. Partiti). Another line at the LMM is characterization of natural materials (ground, sediments, rocks, etc.) with the objective to correlate with ambient parameters (for example, pollution, climate). It is a new area called environmental magnetism.

Development of low-T CEMS detectors (down to 20 K) and Mössbauer Thermal Scan setups are the current instrumentation projects at the Mössbauer lab. Mössbauer measurements can be done with the following facilities:

• 4 Mössbauer spectrometers with ⁵⁷Fe and ¹¹⁹Sn sources

• 12-14 Tesla Superconducting Coil for Mössbauer measurements from 2.3 to 300 K

• Two cryostats for measuring between 4.2 and 300 K

• Mössbauer furnace for measurements from RT to 800 K

• One Nitrogen Cryostat for MS between 80 and 340 K

• One CEMS detector for room-temperature measurements

• Home-made single-channel thermal scanner for determining transition temperatures

Instituto de Física
Universidade de Brasília
Brasília, DF, Brazil

Vijayendra K. Garg (left) and Aderbal Carlos de Oliveira

Names and Titles of Researchers Vijayendra K. Garg, Ph.D. – Research Associate (Responsible for the Group) Aderbal Carlos de Oliveira, Ph.D. – Research Associate George C. B. Braga, Ph.D. – Research Associate Reva Garg, Ph.D. – Research Associate Paulo César de Moraes, Ph.D. – Professor

Areas of Research

The group at Brasília has contributed 150 research papers in Mössbauer spectroscopy, and its research interest lies in the characterization of natural and synthetic samples (minerals, soils, ball milling, biomaterials, inorganic samples, and ferro fluids), and environmental studies. It has available two Mössbauer spectrometers, an Oxford cryostat (liquid nitrogen-variable temperature), a Janis cryostat (liquid helium-variable temperature), an RF susceptometer, a photoacoustics spectrometer, a Curimeter, and standard support facilities of a workshop, including cryogenics and computational facilities. Diverse facilities such as X-rays, micro probe, electron microscope, calorimeter, and chemical analysis are available at the campus in diverse laboratories.

The group collaborates in Brasília with colleagues in chemistry, geology, and biology (for biomaterials) of the National Commission of Nuclear Energy (Brasília), and has collaborated nationally with the research groups of Jose Domingos Fabris and Wagner da Nova Mussel (Belo Horizonte), Paulo Antonio de Souza Jr. (Vitória), Icaro Moreira (Fortaleza), Antonio Lazaro (Anapolis), Luiz Alexandre (Santa Maria), and Maria de Carmo Rangel (Salvador-Bahia), and with some individuals in Ouro Preto. Internationally, the group collaborates with Erno Kuzmann (Hungary), Laszlo Takacs (Maryland), Amar Nath (Philadelphia), K. Nomura (Japan), Kailash Chandra (IIT, Roorkee, India), Deo Raj (PAU, Ludhiana, India), and S. P. Taneja (Rohtak, India).

Laboratório de Espectroscopia Mössbauer e Magnetometria (LEMAG)
Departamento de Física
Universidade Federal do Espírito Santo
Vitória, Espírito Santo, Brazil
www.cce.ufes.br/pos-graduação

Names and Titles of Researchers

Permanent Staff:

Carlos Larica – Researcher
Edson Passamani Caetano – Researcher
Evaristo Nunes Filho – Researcher

Collaborators of LEMAG:

José Rafael Proveti – Post-Doctoral Fellow
Rodrigo Dias Pereira – D.Sc. Student
Célio Marques – M.Sc. Student
Paulo Moscon – M.Sc. Student
Alexandro Masioli dos Santos – M.Sc. Student
Thiago Mathias de Oliveira – Undergraduate Student
Fábio Xavier – Undergraduate Student
André Luis Alves – Undergraduate Student

History and Areas of Research

The Magnetometer and Mössbauer Spectroscopy Laboratory (LEMAG) at the Physics Department of the Federal University of Espírito Santo (UFES) was consolidated in the 1990s, when the Master degree course was created at the Physics Department. It is the unique Mössbauer laboratory in the Espírito Santo state. The LEMAG group currently hosts 11 persons: three staff researchers, one post-doctoral position, one D.Sc., three M.Sc., and three undergraduate students.

The main research interest of the group concerns the synthesis of iron-bearing materials using methods such as arc-melt or high-energy milling and the characterization of their structural and magnetic properties. The on-going projects within the LEMAG group are:

• Magnetic nanoparticles – Studies of the formation and physical properties of iron-based metastable phases (amorphous and nanocrystalline) prepared by the high-energy milling technique. Kinetics crystallization of amorphous metastable phases submitted to thermal annealing is also analyzed under the Avramin approach. Magnetic nanoparticles formation and their magnetic interactions are also investigated. The studied systems include FINEMET, NANOPERM, and HITPERM materials.
  
  

• FINEMET and NANOPERM produced by melt-spinning – Spin reorientation effect induced by mechanical stress is investigated in soft amorphous ribbons produced by melt-spinning and coated by materials with different thermal expansion coefficients.
  
  

• Exchange bias effect in milled materials – Investigation of composite materials produced by high-energy milling, with magnetic interaction at the grain boundaries/interfaces between ferromagnetic (Fe or FeCo) and antiferromagnetic materials (MnO₂, FeMn) that yields unidirectional magnetic anisotropy.
  
  

• Magnetocaloric materials – A LaFe₁₃ based alloy can be a good candidate for application in a commercial magnetic refrigerator. Very recently, the LEMAG group has started the investigation on the magnetic disorder effect induced by the Si, Al in the La,Fe phase. Also, the group is studying the influence of iron substitution by other magnetic elements in order to increase the Curie temperature of the alloy, making it useful for application in domestic refrigerators.

Below is a list of national and international Mössbauer collaborators:

• Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, Brazil: Prof. Elisa Baggio-Saitovitch

• Universidad Nacional Mayor de San Marcos, Lima, Perú: Dr. Victor Antonio Peña Rodríguez

• Universidad Nacional de La Plata, La Plata, Argentina: Prof. Francisco Homero Sánchez

• Katholieke Universiteit, Leuven, Belgium: Prof. André Vantomme

Departamento de Física
Universidade Federal de Santa Catarina
Florianopolis, Brazil

Left to right: Valderes Drago, Cristian Bernardi, and Daniel Girardi

Names and Titles of Researchers Dr. Valderes Drago – Responsible for the Lab Dr. Enio Lima, Jr. – Collaborator Research Daniel Girardi – Master Student Cristian Bernardi – Master Student

Areas of Research

The group at the Departamento de Física, UFSC, is working in the following areas:

• Nanostructured Fe.Ni alloys formed by autocatalytic chemical reduction: metallic alloy spherical particles with diameter between 25 nm to 220 nm are formed by a co-precipitation of reduced Fe+2 and Ni+2 cations by a strong chemical reducing agent. The particles are formed by nanometric (10 nm to 20 nm) crystallites involved in a predominant interfacial (not crystalline) region.
  
  

• Iron nitrides formed in iron grains capped with a thin nickel layer that acts as a catalyst in iron ammonia reactions.
  
  

• Mössbauer analysis of bioinorganic complexes.

Group of Nanostructured Materials, Surface Physics, and Mössbauer Spectroscopy
Laboratório de Física Aplicada – LFA
Centro de Desenvolvimento da Tecnologia Nuclear – CDTN
Comissão Nacional de Energia Nuclear – CNEN
Ministério da Ciência e Tecnologia – MCT
Belo Horizonte, Brazil
www.cdtn.br/~lfa

Areas of Research

The group's actual research lines include the study of the structural and magnetic properties of systems of low dimensionality (epitaxial ultrathin films and multilayers, granular solids, ferrite ultrafine powders, exchange biased ferromagnetic/antiferromagnetic bilayers), Fe alloys, organometallic compounds containing Fe or Sn, and also catalytic processes using Fe oxides. The leader of the group is currently involved in the use of nuclear resonant scattering (NRS) with synchrotron radiation at the ESRF to investigate magnetic nanostructures.

Nanostructures and other materials of interest are/can be prepared in the LFA by evaporation in ultrahigh vacuum (molecular beam epitaxy) and high vacuum (sputtering), sol-gel processing, and other standard methods.

The group also offers services of materials characterization by Mössbauer spectroscopy (⁵⁷Fe and ¹¹⁹Sn), surface and interface analysis by Auger electron spectroscopy, and X-ray photoelectron spectroscopy to the local industry. A description of the available experimental facilities can be found on the group's Web page at <www.cdtn.br/~lfa>.

Departamento de Química
Universidade Federal de Ouro Preto
Ouro Preto, Brazil

Names and Titles of Researchers

Dr. Geraldo Magela da Costa – Head of Laboratory
Valdirene Gonzaga de Rezende – Student

History and Areas of Research

The Mössbauer laboratory in the Chemistry Department at UFOP started its activities in 1998, and has run continuously since that time. The lab has one spectrometer and a small furnace-cryostat capable of operating between 77 K and 600 K. The main subjects of investigation are the study of iron ores, synthetic iron oxides, and natural and synthetic minerals.

Departamento de Química
Universidade Federal do Paraná
Curitiba, Paraná, Brazil

Names and Titles of Researchers

Fábio Souza Nunes – Supervisor
Angela C. Raimondi – Graduate Student
Núbia D. dos Santos – Graduate Student
Gisele M. Protasiewyck – Graduate Student
Heron Vrubel – Undergraduate Student
Fernanda F. Moreira – Undergraduate Student
Fabiana H. Ishiruji – Undergraduate Student
Leandro J. Cavichiolo – Undergraduate Student

Areas of Research

The group's main interest is the synthesis, spectroscopic characterization, and reactivity of protein model complexes, particularly iron proteins such as nitrogenase and hemoglobin. We have a special interest in iron, vanadium, ruthenium and molybdenum macrocyclic and trinuclear carboxylate complexes. The Mössbauer analysis is run at the University of Sussex (UK) with the collaboration of Dr. David John Evans.

Mössbauer Spectroscopy Laboratory
Departamento de Física
Universidade Estadual de Maringá
Maringá, PR, Brazil

Names and Titles of Researchers Dr. Andrea Paesano Jr. – Scientist/Laboratory Supervisor Dr. Ivair Aparecido dos Santos – Scientist Dr. Suzana Nóbrega de Medeiros – Scientist Dr. José Flávio Borges – Visiting Scientist Luiz Fernando Cótica, M.Sc. – Ph.D. Student Shalimar Calegari Zanatta, M.Sc. – Ph.D. Student Célia Kimie Matsuda, M.Sc. – Ph.D. Student Valdecir Biondo – M.Sc. Student Flávio Takashita – M.Sc. Student Marcos Guerreiro – M.Sc. Student

History and Areas of Research

The Mössbauer Spectroscopy Laboratory of Maringá State University was implemented in June 1998 as the result of a partnership connecting University departments such as Physics, Materials Science, Chemistry, Engineering, and Mineralogy and members of the research local community. At the beginning, thin solid multilayered films were mainly investigated, concerning the solid state reaction induced by thermal annealing. Minerals and soils also received much attention. The research group then started measuring hyperfine fields in permanent magnetic materials, such as the pseudo-binary compounds RE₂(Fe,TM)₁₇ and RE₂(Fe,TM)₁₄B. Hydrides and nitrides of these compounds, prepared by electrochemical and gas-solid reaction processes, are currently being investigated. Recently, the group has focused on mixed oxides of the type Fe-M₂O₃ or Fe₂O₃-M₂O₃ (M = TM, RE), prepared by high-energy ball-milling. The aim of this investigation is to identify and quantify the phases formed by mechanical alloying and propose models based on kinetics and thermodynamic parameters to explain the observed results. Also as a part of the latest activities, a source for Mössbauer in Gd¹⁵⁵ (i.e., SmPd₃) was entirely prepared by the group, and is currently employed to analyze the UO₂-Gd₂O₃ nuclear fuel for electrical energy generating nuclear plants.

Laboratorio de Físico-Química de Suelos
Departamento de Ciencias de los Materiales
Universidad de Santiago de Chile
Santiago, Chile

Names and Titles of Researchers Dr. Mauricio Escudey – Head Leader Dr. Gerardo Galindo Dr. Juan Enrique Förster Dra. Marcia Cazanga Dra. Carmen Pizarro – Scientist in Mössbauer Spectroscopy Katherine Avendaño – Graduate Student Raúl Calderon – Graduate Student Mariela Acuna – Undergraduate Student Carolina Ancavil – Undergraduate Student Nicolás Arancibia – Undergraduate Student Susana Aravena – Undergraduate Student Laura Barraza – Undergraduate Student Manuel Borquez – Undergraduate Student Marlén Gutierrez – Undergraduate Student Pamela de la Fuente – Undergraduate Student Karen Manquian – Undergraduate Student Cristina Morales – Undergraduate Student Magdalena Quinteros – Undergraduate Student Antonio Reyes – Undergraduate Student Justo Torres – Undergraduate Student Verónica Vicuna – Undergraduate Student

Mauricio Escudey Carmen Pizarro

Areas of Research

• Surface charge in soils and catalysts

• Cation exchange equilibria

• Determination of P-forms in soils by chemical fractionation and ³¹P-NMR methods

• Experimental studies and modeling of thermal impact on soils

• Studies of sewage sludge impact (P, N, exchangeable bases, heavy metals): Leaching studies, kinetic and equilibria studies in diffusion cell

• Chemical speciation in soil solution and soil extracts

• Mössbauer Spectroscopy

Research in Mössbauer spectroscopy is focused in the mineralogical analysis of iron oxides of Chilean volcanic soils. About 70% of agricultural activities of Chile are carried out in these soils. They are characterized by a mineralogy dominated by non-crystalline compounds, which cannot be analyzed by conventional chemical and physical methods.

Incomplete or ambiguous results have been obtained by Mössbauer spectroscopy when samples of complete Chilean Andisols and Ultisols are used. Based on this information, new analytical strategies have been designed to overcome the difficulties. A procedure based on the previous physical preparation of the magnetic compounds of the sand fraction and the subsequent dissolutive treatment of clay and silt fractions with 5 M NaOH was developed for volcanic soils.

Now the group is enhancing the strategy of analysis. Selective dissolutive procedures such as ammonium oxalate, citrate-ascorbate, dithionite-citrate-bicarbonate and sodium pyrophophate, combined with Mössbauer spectroscopy, XRD, specific magnetization, and chemical analysis have been used.

The research group is also interested in the study of the role of Fe oxides in oxidation reactions of organic contaminants in gaseous or acqeous phase, which may have technological applications.

Collaboration work is carried out with:

• Dr. Nelson Moraga (Engineer, USACH) – Expert in numeric methods

• Dr. Gustavo Zúñiga (Vegetal Physiologist, USACH) – Expert in plant growth studies

• Dr. José Domingos Fabris (Engineer, Universidade Federal de Minas Gerais, Brasil) – Expert in Mössbauer spectroscopy

• Dr. Andrew Chang (Engineer, University of California, Riverside, USA) – Expert in sewage sludge and residuals water treatments

• Dr. Olivier Fudym (Engineer, Ecole de Mines d’Albi, Francia) – Expert in thermophysical parameters determination

Departamento de Física
Universidad del Valle
Cali, Colombia

Names and Titles of Researchers Germán Antonio Pérez, Ph.D. – Director Alberto Bohórquez Gallo, Ph.D. Jesús Anselmo Tabares, Ph.D. Ligia Edith Zamora Alfonso, Ph.D. Héctor Sánchez, Ph.D. Mónica Maria Rico Castro, Ph.D. Humberto Bustos – Doctoral Student Dagoberto Oyola – Doctoral Student Faustino Reyes, M.Sc. – Doctoral Student William Richard Aguirre C., M.Sc. – Doctoral Student Milton Medina, M.Sc. – Doctoral Student Giovanny Medina, M.Sc. – Doctoral Student Modesto Fajardo, M.Sc. – Doctoral Student Victor Rodriguez, M.Sc. – Doctoral Student John Fabio Valderruten – Doctoral Student Juan David Betancur - Doctoral Student Ruby Rocío Rodríguez - Doctoral Student Willian Barona – Doctoral Student Hernan Colorado – Master Student John Ipus – Undergradute Student Otto Reina – Undergraduate Student

Germán Antonio Pérez

Areas of Research

Research at the Departamento de Física, Universidad del Valle, is in the following areas:

• Magnetic, mechanical, corrosive, and structural properties of FeMnAl
  
  

• FeNi, and FeSi alloys produced by arc furnace, mechanical milling, and sinterization
  
  

• Theoretical studies of magnetic properties of FeMnAl alloys using the Ising and Heisenberg models and the Monte Carlo method
  
  

• Nuclear techniques in coal mines, and different Colombian mineral mines
  
  

• Study of ⁵⁷Fe thin films by Mössbauer spectroscopy, DCEMS
  
  

• Magnetism of nanostructured materials studied by Mössbauer spectroscopy and ac magnetic susceptibility

Mössbauer Line, Solid State Group
Instituto de Física
Universidad de Antioquia
Medellín, Colombia

Standing from left to right: Jailes Beltran, Juan Manuel Florez, Jorge Hamann, Luis Carlos Sanchez, Johan Mazo, Cesar A. Barrero, Johans Restrepo, Jorge E. Tobon. Sitting from left to right: Jorge Lopez, Jorge Otalora, Alvaro Velasquez, Alvaro L. Morales, Karen E. Garcia

Names and Titles of Researchers

Cesar A. Barrero – Researcher
Alvaro L. Morales – Researcher
Johans Restrepo – Researcher
Jorge E. Tobon – Researcher
Karen E. Garcia – Ph.D. Student
Johan Mazo – Ph.D. Student
Alvaro Velasquez – Ph.D. Student
Jailes Beltran – Undergraduate Student
Juan Manuel Florez – Undergraduate Student
Jorge Hamann – Undergraduate Student
Jorge Lopez – Undergraduate Student
Jorge Otalora – Undergraduate Student
Luis Carlos Sanchez – Undergraduate Student

Areas of Research

• Synthesis of iron oxides, pure and doped, related to corrosion products such as akaganeite, lepidocrocite, goethite, magnetite, maghemite, and hematite
  
  

• Corrosion tests in the laboratory to simulate corrosion in different steels and environments, such as immersion-emersion tests, total immersion, environmental camaras, and field expositions
  
  

• Study of rust converters to see effects on rust and conversion to products that will help to stop further deterioration
  
  

• Production of iron oxide thin films by sputtering DC and AC
  
  

• Use of the Monte Carlo method to simulate magnetic properties of iron oxides and relate them to experimental results
  
  

• Building of Mössbauer instrumentation – The group has already built their own Mössbauer spectrometer (except for the detector and transducer), and a transducer is being built now

Instituto de Materiales y Reactivos
Universidad de La Habana
La Habana, Cuba

Names and Titles of Researchers

Dr. Edilso Reguera
Dr. José Fernández-Bertrán
Dr. Jorge Balmaseda
Dr. Alma Valor-Reed
Dr. Julio Duque-Rodríguez
Dr. Armando Paneque
M.Sc. Jorge Roque
M.Sc. Joelis Rodríguez-Hernández – Ph.D. Student
M.Sc. Ricardo Martínez-Garcia – Ph.D. Student
M.Sc. Osvaldo Estevez-Hernández – Ph.D. Student
B.Sc. Leslie Reguera – M.Sc. Student

Areas of Research

• Molecular Materials: Molecular blocks assembling in materials development; 3-D porous structures; functional materials; porphyrins and related compounds; tuning of material properties through external stimuli
  
  

• Environment Effect on Materials: Materials as sensors of environmental changes; correlation of environmental parameters and properties of corrosion products; environmental samples
  
  

• Applications of Combined Techniques to Obtain Information on the Crystalline and Electronic Structure of Materials: XRD, EXAFS, CPMAS NMR, Mössbauer, IR-Raman; adsorption and transport techniques in porous materials; thermal methods

Mössbauer Group
Instituto Superior de Ciencias y Tecnología Nucleares
Habana, Cuba

Names and Titles of Researchers Dr. Norma Raisa Furet Bridon – Director of Group Dr. Diego Luis Orihuela Calvo – Visiting Scientist Lic Juan Carlos Hernandez – Visiting Scientist Tec. Carmen Portilla Vergara – Technician

Norma Raisa Furet Bridon

Areas of Research

At the present time, the group at the INSTEC are involved mostly in the application of the Mössbauer effect on the study of weathered soil, chemically poor soil, and the study of sediments from didferent zones in Cuba. The study of chlorosis problems in calacareous soils is another topic of research. In this way, the correction of nutrient imbalance in soil is one of the objects of the research, using a product based in iron metallic sulfate. The characterization of the mixture of solid wastes with iron metallic sulfate that are used as fertilizers in soil and the study of mud are also objects of the group’s research tasks.

The group has scientific collaborations with the Mössbauer Spectroscopy Laboratory at the Universidad de Panama and the Laboratoire de Chimie Physique et Microbiologie pour l’Environnement at the Université Henri Poincare-Nancy I in France, with the Laboratory of Mössbauer Spectroscopy of the Universidad Nacional Mayor de San Marcos in Peru, and with the Laboratory of Mössbauer Spectroscopy of Université du Main in Le Mans, France.

Programa de Ingenieria Molecular Molecular
Instituto Mexicano del Petróleo
México, México

Names of Researchers

Ing. German Vazquez P
Dr. Hector Armendariz
Dr. Jesus Mobarak
Dra. María Elena Llanos
Dr. Noel Nava

Areas of Research

The application lines concerning Mössbauer spectroscopy are focused mainly on the study of heterogeneous catalysis for application in the oil refining and petrochemical industries. In the past few years the following research areas involving Mössbauer spectroscopy studies have been explored:

• Non-supported mixed oxide catalysts (Fe-Zn-O and Fe-Zn-Cr-O) for oxidative dehydrogenation of n-butene and 1-butene to butadiene. The Mössbauer spectroscopy technique has been used to elucidate the nature of active sites presents on bulk mixed oxides, as well as the cooperative effect of different phases present in the solids on its catalytic behavior.
  
  

• Supported mixed oxide catalysts for oxidative dehydrogenation of n-butene and 1-butene to butadiene. In order to increase the exposed area of bulk mixed oxides, these materials were supported on silica and alumina. The Mössbauer spectroscopy technique has been used to show the effect of support on the electronic properties of active sites presents on bulk mixed oxides on its catalytic behavior.
  
  

• Mössbauer spectroscopy has been also applied with success in the development of supported platinum-tin catalysts, which are widely used for the normal dehydrogenation of low molecular weight parafins (propane, butane, and isopentane).
  
  

• In order to study the problems of corrosion in ducts and heat exchangers, the Conversion Electron Mössbauer (CEM) technique has been used.

Instituto Nacional de Investigaciones Nucleares
México, México

Names of Researchers

M.Sc. Hector Flores Llamas – Depto. de Física
Dr. Agustín Cabral Prieto – Depto. de Química

Areas of Research

The research activities in which the group has been working recently include:

• Amorphous alloys
  
  

• Fe₇₈Si₉B₁₃ – results to be presented at LACAME 2004

• Fe₄₀Ni₄₀B₂₀

• Fe₇₀Cu₂₅B₅

• Fe₄₅Cu₄₅B₅

• Fe₃₀Cu₆₅B₅

• All these alloys (except Fe₇₈Si₉B₁₃) are produced by chemical reduction. The group intends to hydrogenate these materials in the near future.
  
  

• Arqueometry – Mexican ceramics
  
  

• Contaminants of Cr with iron

Departamento de Química Física
Centro de Investigaciones con Técnicas Nucleares
Universidad de Panamá
Panamá, Panamá

Names and Titles of Researchers Dr. Juan A. Jaen – Coordinator Dr. Agnes Foti de Bosquez – Scientific Collaborator Lic. Elizabeth Garcia de Saldaña, M.,Sc. – Researcher Lic. Griscelda Caballero de Sanchez – Researcher Lic. Abdiel Aponte, M.Sc. – Scientific Collaborator Gerardo Garibaldi – Student Itzel Adames – Student

Juan A. Jaen and Student

Areas of Research

Dr. Jaen’s group at the Department of Physical Chemistry, University of Panama, has been doing work in a variety of corrosion related problems, applying Mössbauer spectroscopy among other techniques such as FTIR and X-ray diffraction. Subjects of interest are short-term exposure of carbon steel in tropical atmospheres, characterization of iron oxides in materials, the role of spinel phase in corrosion, the role of nanophase goethite in corrosion, atmospheric corrosion inhibitors, the role of tannins and related compounds in corrosion protection, chemical cleaning agents, anticorrosive paints, electroformed alloys, and synthesized corrosion products by iron hydrolysis.

The group is also interested in starting work using Mössbauer spectroscopy combined with classical geochemical methods to study ecological and environmental oriented problems in soils, aquatic sediments (river, lake, and marine), and others.

Laboratorio de Magnetismo
Escuela de Física, Facultad de Ciencias
Universidad Central de Venezuela
Caracas, Venezuela

Names and Titles of Researchers Dr. Fernando González-Jiménez – Professor Dr. Lisseta D’Onofrio – Professor Edgar Jaimes, M.Sc. – Assistant Professor Boutros Pierre Embaid, M.Sc. – Instructor-Professor Angel Rivas, M.Sc. – Ph.D. Student Lic. Aly Perez – M.Sc. Student Lic. Heidi Martinez – M.Sc. Student Bach. Belkis Colmenares – Lic. Student

Areas of Research

Research taking place presently at the Lab combines fundamental topics with others related to possible applications in Venezuela:

• Mössbauer spectroscopy applied to catalysis: Catalytic improvement of heavy crude oils by means of hydrotreatment reactions whose active phases are mixed (Fe, M) sulfides (M = V, Ni, Mo, W)
  
  

• Mössbauer spectroscopy and magnetic measurements applied to the study of magnetic anomalies associated with oil reservoirs and other applications to geology
  
  

• Study of the magnetic and electronic properties of low dimensionality systems: Study of iron oxi-hydroxide or metallic nanoparticles of natural origin or synthesized by organometallic techniques and fixed in polymers
  
  

• Study of itinerant antiferromagnetism (Spin Density Waves) in systems such as CuFeSe₂ (quasi 1D) and CuFeTe₂ (2D)

The group has wide collaborations with:

• Centro de Catalisis, Escuela de Química, Universidad Central de Venezuela, Caracas [Drs. C. Scott, M. Goldwasser, M.L.Cubeiro]

• Laboratorio de Aplicaciones de Tecnicas Nucleares, Facultad de Ingenieria, UCV, Caracas

• Centro de Semiconductores, Facultad de Ciencias, Universidad de Los Andes, Mérida [Dr. J. Gonzalez]

• Escuela de Geologia, Ingenieria, UCV, Caracas [Dr. F. Urbani]

• In France, with Dr. Pierre Bonville (Commissariat à l’Energie Atomique), Profs. François Varret and Jorge Linares (Université de Versailles), and Prof. Jean Marc Broto (Université Paul Sabatier, Toulouse)