Antiferromagnetic order of the lanthanoid moments in the carbides Ln 2ReC 2 with Ln = Tb, Dy, Ho and Er

Abstract

The order of the magnetic moments of the lanthanoid atoms in the orthorhombic carbides Dy 2ReC 2 and Ho 2ReC 2 has been determined from neutron powder diffraction data recorded at low temperatures. The antiferromagnetic structures conform to the nuclear cell. They were determined using Bertaut's representation analysis. The magnetic structure of the dysprosium compound is similar to that determined previously for the carbide Er 2ReC 2. Both can be characterized with the basis function [ G x , A y , A z ], while the magnetic structures of Ho 2ReC 2 [ A x , O, G z ] and the earlier characterize compound Tb 2ReC 2 [0, A y , 0] are different. Magnetization measurements with a SQUID magnetometer reveal the four carbides to be metamagnetic. The magnetic order in Tb 2ReC 2 ( T N = 96 K), Ho 2ReC 2 ( T N = 58 K), Ho 2ReC 2 ( T N = 30 K) and Er 2ReC 2 ( T N = 18 K) was monitored by temperature-dependent neutron diffraction up to the Néel temperatures of these carbides.