Magnetic Properties of Laves Phase RRu₂ Compounds (R=Gd, Tb, Dy, Ho and Er)

Abstract

Magnetic studies have been performed on single crystals of the C-14 type Laves phase RRu₂ (R=Gd, Tb, Dy, Ho and Er) and the pseudo-binary (R_1−xY_x)Ru₂ (R=Tb, Dy, Ho and Er) compounds in the temperature range from 4.2 K to 300 K. DyRu₂ shows a transition from cone structure to ferromagnetic one at 15 K and the other RRu₂ compounds exhibit ferromagnetism. The magnetization curves of the RRu₂ single crystals show their own characteristic behaviors dependent on the sort of R atoms. Lower moments for all RRu₂ compounds except GdRu₂ are observed at 4.2 K. The results are interpreted in terms of the single ion Hamiltonian including applied field, molecular field and crystal electric field (CEF) terms. From the analysis, the B_n^m(n≥4) terms were found to be dominant in this system. Tlne bi-quadratic exchange interaction seems to contribute to magnetic properties in TbRu₂ and DyRu₂.