Competing ferro- and antiferromagnetism in R 2CuIn 3 (R=Tb, Ho, Er) intermetallics studied by neutron diffraction and magnetization measurements

Abstract

Ternary R 2CuIn 3 (R=Tb, Ho, Er) intermetallics were investigated by means of neutron diffraction and low-temperature susceptibility measurements. The Tb and Ho samples exhibit antiferromagnetic (AF) behavior with T ord=33±1 and 9 K, respectively, while the Er compound reveals peculiar almost re-entrant spin glass (RSG) characteristics with a critical temperature T crit =12 K and a broad maximum at T ord =9±1 K . Neutron diffraction profiles at 3.8 K confirm collinear AF order only for Tb 2CuIn 3 with a magnetic moment μ (3.8 K) =6.8 μ B /Tb 3+ localized on the R ions only and aligned along the c-axis. The absence of any long-range order in the Ho and Er compounds may be attributed to local spin disorder and dynamical spin fluctuations. Spinglass-like states, cannot be excluded when the structural disorder on the 2d site, introduced by the statistical distribution of Cu and In ions, is considered.