Jean-Marc was awarded his thesis of Troisième Cycle in the same laboratory in 1981, devoted to the magnetic properties of metallic glasses, combining particularly the analysis of Mössbauer spectra with broadened lines, the ferromagnetic domains texture, and its description in relation to the quenching technique mechanism. As volunteer to non-active military service, Jean-Marc went to the Universidad de Ingenieria de Lima (Peru) from October 1981 through March 1983, where he taught solid-state physics. He enjoyed this period because of the friendly atmosphere of Peruvians as well as that of South America as a whole, but he also discovered the difficulties of doing research in such a country, where the economic situation is completely dependent on that of Northern countries. Indeed, the professors are poorly paid and there are few instrumental facilities, even now.

Upon his return to France, Jean-Marc joined CNRS (Centre National de la Recherche Scientifique) in 1983 as a permanent researcher in the group of Professor Varret, who is now at the University of Versailles Saint-Quentin (France). The next four years were devoted to research in the framework of his Ph.D. (1987), which was the study of structural, magnetic, and hyperfine properties of amorphous ferric fluorides – FeF₃ – a fascinating system from the structural and magnetic point of view. Indeed, it exhibits a polymorphism of three crystalline phases and amorphous phases (a nanostructured variety was recently obtained and studied), and the presence of both antiferromagnetic interactions and cationic topologies, giving rise to different non-collinear magnetic structures. This work was performed in collaboration with Professor F. Varret, Professor J.M.D. Coey (Trinity College, Dublin, Ireland), Professor Jacques Teillet (now at the University of Rouen, France), and Professor Gérard Ferey and Professor Marc Leblanc (now at the University of Versailles Saint-Quentin and the University of Le Mans, respectively). After receiving his Ph.D., he joined Dr. Gordon Czjzek at Kernforschungzentrum Karlsruhe (Germany) as an A. Von Humboldt fellow for one year. In 1997, he was promoted to the position of CNRS Research Director.

After François Varret left Le Mans for Paris, Jean-Marc developed a research group now composed of five permanent teachers at the University of Le Mans, which has been a part of the Laboratoire de l’Etat Condensé (UMR CNRS 6087) for the last 15 years. The main research topics are particularly oriented to the understanding of structural and magnetic properties of magnetic nanomaterials, either nanoparticles, nanocrystalline alloys, or nanostructured powders, and the role of surface, interface, or grain boundaries. On one hand, experimental studies are performed thanks to the particularly well-organized instrumentation facilities around Mössbauer spectrometers, allowing low and high temperatures, as well as magnetic field to be achieved. On the other hand, numeric facilities are now possible after building homemade Beowulf-type computer clusters. These instrumental facilities are quite attractive, and have originated a certain number of bilateral collaborations supported by either CNRS, the French Ministry of Foreign Affairs, or the French Ministry of Education, favoring thus a venue of numerous students (in the frame of co-tutelle Ph.D.) and colleagues from different countries (i.e., Poland, the Slovak Republic, Colombia, Argentina, Algeria, Germany, Spain, Ireland, Romania, Morocco, and South Korea). The research group is also currently involved in some international projects supported by the European Community and NATO. Consequently, Jean-Marc is very pleased with the international atmosphere and the mixture of cultures that occurs in his research group. He is also very fond of giving lectures either at the University of Le Mans, or at different universities with which he is collaborating, particularly in South America (Colombia, Peru) and Northern Africa. He is also thinking in new topics for the next five years, probably solid-state physics applied in environmental and biological sciences.

During the last 10 years, he has been invited to about 60 national and international workshops, schools, and conferences and has been several times a member of organizing and scientific committees of international conferences. In addition, Jean-Marc is a permanent referee for different international reviews, for the European Community, and for MPST (the French Committee of Pedagogy, Science and Technology) and recently became a Consulting Scientist at Alcan-Pechiney Company. He was the Chairman of the French Group of Mössbauer Spectrometry and became a French representative on the International Board on the Applications of the Mössbauer Effect (IBAME). More recently, he was elected as Secretary of IBAME.

Jean-Marc is often fighting with French administrative rules (how to buy a computer, or a train ticket), which he finds to be time- and energy-consuming, and which he believes prevent people from working in optimal conditions and having great initiatives. Some of his hobbies are painting, biking, reading, and photography, and he is very interested in different cultures.