Magnetization and magnetic anisotropy of R2Fe14B measured on single crystals

TLDR

The study investigates the relationship between magnetocrystalline anisotropy and sublattice magnetization in R₂Fe₁₄B compounds using a simplified two‑sublattice molecular field model. Temperature‑dependent measurements of saturation magnetization, anisotropy field, and easy‑axis angle were performed on single‑crystal R₂Fe₁₄B samples (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm) from 4.2 K to their ordering temperatures, and the data were analyzed within the two‑sublattice model. Spin‑reorientation transitions were observed at 57.6 K in Ho₂Fe₁₄B and in Er₂Fe₁₄B/Tm₂Fe₁₄B, the latter driven by anisotropy compensation between Fe and R sublattices.

Abstract

The temperature dependence of the saturation magnetization and the magnetocrystalline anisotropy field have been measured on single-crystal samples of the R2Fe14B compounds for R=Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm from 4.2 K to the magnetic ordering temperatures. A spin reorientation transition of the Nd2Fe14B type has been found in Ho2Fe14B at 57.6 K in zero field. Another type of spin reorientation caused by anisotropy compensation between the Fe and the R sublattices exists in Er2Fe14B and Tm2Fe14B. The temperature dependence of the angle of the easy direction of magnetization from the c axis has been measured for R=Nd, Ho, Er, and Tm. The relation between the magnetocrystalline anisotropy and the sublattice magnetization is investigated by employing a simplified two-sublattice molecular field model.