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Neutron and bulk investigations of nanocrystalline Sm$_{1-x}$y$_{x}$Co$_{5}$: a new route towards hard permanent magnets


A detailed understanding of the physics underlying permanent magnetism is of major importance for the development of new high-tech materials for applications ranging from efficient data storage and transport to generation and distribution of energy. In this context, we propose an investigation of the magnetic and structural properties of nanocrystalline samples in the solid solution Sm$_{1-x}$Y$_{x}$Co$_5$ using neutron scattering and bulk measurement techniques. The project is partly motivated by several recent reports of improved performance in nanocrystalline versions of several permanent magnets. Combining this with the controlled substitution Y on the Sm sites in the alloy will help us to gain a better understanding of how the interplay between electronic degrees of freedom, particle size, and reduction of the magnetic connectivity combine to generate the magnetic properties of permanent magnets, hence paving the way for high performance and low cost hard permanent magnets. Stimulated by this challenge, we request financial support from FAPESP to launch a collaboration between the research group headed by a recognized expert in neutron scattering, Dr. G{\o}ran Nilsen, from the ISIS Neutron and Muon Facility, Rutherford Appleton Laboratory (ISIS-RAL) and the research group headed by Prof. Larrea at Department of Physics Materials in the Institute of Physics of University of São Paulo (DMFT-IFUSP). The financial support provided by FAPESP will help to cover the visit of Dr. Nilsen at USP within the period of October-November 2020, in the modality of Visiting Researcher. Besides the scientific interest of the project, the work plan will also include teaching by Dr. Nilsen in our Postgraduation Program on the cutting-edge applications of neutron scattering experiments in condensed matter physics, as well as at two other institutions, the Brazilian Synchrotron Light Laboratory (LNLS) and the School of Engineering of Lorena (EEL-USP).The success of the project relies on the active collaboration between the participants: the preparation of solid solution nanocrystalline samples and bulk magnetic property characterization will be carried out by the groups of Prof. Larrea and Prof. Cornejo at DMFT-IFUSP whereas the initial neutron scattering experiments will be covered by Dr. Nilsen. The neutron scattering data will be analyzed collaboratively following training of DMFT-IFUSP staff by Dr. Nilsen during his visit. Finally, the funds assigned to the project will help to boost the Young Investigator JP project of Prof. Larrea (Process Number 2018/08845-3), who has committed to establish collaborations between research groups worldwide, particularly ones hosting experimental facilities which do not yet exist in Brazil. This will help to promote the development of highly skilled undergraduate and postgraduate students, and to extend access to state-of-the-art neutron facilities to possible users in the state of São Paulo. (AU)