| AVS 65th International Symposium & Exhibition | |
| Actinides and Rare Earths Focus Topic | Thursday Sessions |
| Session AC-ThP |
| Session: | Actinides and Rare Earths Poster Session |
| Presenter: | Lev Ivanov, M.V. Lomonosov Moscow State University, Russian Federation |
| Authors: | I. Tereshina, M.V. Lomonosov Moscow State University, Russian Federation L. Ivanov, M.V. Lomonosov Moscow State University, Russian Federation D. Gorbunov, Helmholtz-Zentrum Dresden-Rossendorf, Germany M. Paukov, Charles University, Prague, Czech Republic E.A. Tereshina-Chitrova, Institute of Physics, Academy of Sciences of the Czech Republic M. Doerr, Technische Universität Dresden, Germany L. Havela, Charles University, Prague, Czech Republic A.V. Andreev, Institute of Physics ASCR, Czech Republic |
| Correspondent: | Click to Email |
Since the discovery in 1984, the R2Fe14B (R is a rare earth) compounds received a considerable scientific attention due to their hard magnetic properties [1,2]. Fundamental characteristics of the best permanent magnet Nd2Fe14B are known to be highly sensitive to the atomic substitutions and absorbed light atoms such as hydrogen. In the present work, we studied a combined influence of substitutions of Er and Tm for Nd and hydrogen absorption on the behavior of magnetization in magnetic fields up to 60 T. All studies were conducted on free powder samples at 2 K.
It is found that the substitution in the rare earth sublattice decreases the saturation magnetization as a result of ferrimagnetic ordering of magnetic moments of heavy rare earths with respect to the moments of Nd and Fe. However, under sufficiently strong magnetic fields the magnetic moments rotate and in the ideal case, the field-induced ferromagnetic state is observed. This phenomenon is directly connected to the strength of the inter-sublattice exchange interactions (Fe and Nd, Er, Tm sublattices).
In the parent materials (Nd0.5Er0.5)2Fe14B and (Nd0.5Tm0.5)2Fe14B in fields up to 60 T no increase of the magnetization was observed. Hydriding of the compounds up to the maximum possible hydrogen content 5.5 at.H/f.u. allows us to observe a forced-ferromagentic state in the (Nd0.5Tm0.5)2Fe14BH5.5 compound. The transition from ferri- to the ferromagnetic state occurs gradually: it begins at the 35 T field and finishes at 55 T. For the compound (Nd0.5Er0.5)2Fe14BH5.5 we also observe a magnetization increase. So that, hydrogenation is found to weaken the intersublattice exchange interaction in these three-sublattice materials.
This work is performed with financial support of the grant of Russian Scientific Foundation (project № 18-13-00135). We acknowledge the support of HLD at HZDR (member of the European Magnetic Field Laboratory) and the Materials Growth and Measurement Laboratory (https://mgml.eu [https://mgml.eu/]).
[1] J. F. Herbst, Rev. Mod. Phys . 63, 819 (1991).
[2] O . Gutfleisch et . al . Advanced Mater . 23 (7), 821 (2011).