The effect of rhodium substitution on the magnetic phase transitions in Ho(Co 1− cRh c) 2

Abstract

A detailed study has been made of the magnetic properties of the cubic Laves phase compounds Ho(Co 1- c Rh c ) 2 with c = 0.02; 0.05; 0.08; 0.12; 0.16 and 0.25; with particular attention given to the nature of magnetic phase transitions. Pronounced discontinuities are observed at the magnetic ordering temperature of the compounds with c < 0.1, indicative of a predominantly first order magnetic phase transition. In alloys with c > 0.1 the transition is second order. However, the change from first order to second order is not sudden but gradual. This change in the character of phase transition has been attributed to a reduction in the exchange field acting on cobalt atoms as a result of rhodium substitution. This series has been compared and contrasted with Ho(Co 1− c X c ) 2, where X = Ni and Cu.