Michio Shimotomai1, Hideyuki Fujisawa2 and Masao Doyama1
1Department of Materials Science, Faculty of Engineering, The University of Tokyo, Tokyo
We have designed an SmFe2-based pseudo-binary Laves phase compound in which the spin-reorientation arises around room temperature, taking into account the effects of the crystalline electric field and the atomic size of the constituent elements. Theoretical calculation of the easy-axis diagrams based on the interaction of 4f electrons with the crystalline electric field has predicted that a half substitution of Pr atoms for Sm atoms in SmFe2 raises the spin-reorientation temperature from 175 K to room temperature. such an alloying effect is not expected for other light rare earth elements. We have synthesized a compound with the optimum composition, i.e. Pr0.5Sm0.5Fe2, using the technique of high pressure. Its spin-reorientation temperature, as determined by the Mössbauer spectroscopy, is near room temperature in good agreement with the theoretical design. This compound could be applied as a magnetostrictive and magnetoelastic material. We have found that the magnetic anisotropy of PrxSm1-xFe2 is described by the single-ion crystalline electric field model in the whole range of the composition and that the lattice parameter deviates distinctly from the Vegard' law like some of pseudo-binary intermediate valence compounds.
PrxSm_1-xFe2, Laves phase compound, materials design, crystalline electric field, magnetic anisotropy, high pressure, Mössbauer effect
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