The strength of the R-T exchange coupling in R2Fe14B compounds; an approach based on high-field magnetization measurements

Abstract

By performing high‐field magnetization measurements on Gd₂Fe_14−xMn_xB and Tb₂Fe_14−xMn_xB powdered samples that are oriented in the sample holder by the applied field it is possible to improve the accuracy of earlier reported values for the R‐T exchange‐coupling constant of these R₂Fe₁₄B compounds. In addition, the two‐sublattice model that has been applied previously has been extended to a three‐sublattice model with two magnetic rare‐earth sublattices for the Er and Tm compounds in an attempt to describe the experimentally observed low‐field susceptibility. It turns out however, that mainly the iron‐manganese sublattice is responsible for this susceptibility.