R. Justin Joseyphus received his Ph.D. in the area of nanocrystalline magnetic materials from the University of Madras in 2005. He pursued his post-doctoral research at Tohoku University, Sendai, Japan, till 2007. Later, he joined the Department of Physics, National Institute of Technology, Tiruchirappalli, India as a faculty and currently serves as a professor. His research interests are on the structure-property correlation in magnetic materials using various characterization techniques, with Mössbauer spectrometry one among them. Jean-Marc Greneche received his Ph.D. in 1987 in the area of Physics and Materials Science from the University of Le Mans (France) and joined CNRS (France) in Le Mans as a researcher in 1983. His main scientific activities are devoted to magnetic materials, including crystalline, amorphous and nanostructures, using essentially Mössbauer spectrometry. He has developed an attractive instrumental infrastructure with temperature and magnetic field experiments, allowing numerous national and international collaborations. In addition, he was a member of the executive board of the International Board on Applications of Mössbauer Effect and was editor of several journals.