Multiple magnetic transitions in single-crystal Gd₅Rh₄Ge₁₀

Abstract

Compounds belonging to the R₅Ir₄Si₁₀ family exhibit a variety of ground states depending on the nature of the rare-earth element R. In this work, we report resistivity, magnetization, and heat-capacity studies on a single crystal of Gd₅Rh₄Ge₁₀. Unusual multiple magnetic transitions are observed in Gd₅Rh₄Ge₁₀ (where there is no crystal-field contribution). It appears that one of the four-fold transitions which occurs at the highest temperature is a second-order (continuous) phase transition while the other three probably involving moment reorientations and noncollinear amplitude modulations. In general, the basic cause of the magnetic orderings is due to anisotropic indirect exchange interaction (Ruderman-Kittel-Kasuya-Yasida type) coupled with multiple site occupancy of the Gd atoms.