ANTIFERROMAGNETIC ORDER OF THE LANTHANOID MOMENTS IN THE CARBIDES LN(2)REC(2) WITH LN=TB,DY,HO AND ER

The order of the magnetic moments of the lanthanoid atoms in the ortho rhombic carbides Dy2ReC2 and Ho2ReC(2) has been determined from neutro n powder diffraction data recorded at low temperatures. The antiferrom agnetic structures conform to the nuclear cell. They were determined u sing Bertaut's representation analysis. The magnetic structure of the dysprosium compound is similar to that determined previously for the c arbide Er2ReC2. Both can be characterized with the basis function [G(x ), A(y), A(z)], while the magnetic structures of Ho2ReC2 [A(x), 0, G(z )] and the earlier characterized compound Tb2ReC2 [0, A(y), 0] are dif ferent. Magnetization measurements with a SQUID magnetometer reveal th e four carbides to be metamagnetic. The magnetic order in Tb2ReC2 (T-N = 96 K), Dy2ReC2 (T-N = 58 K), Ho2ReC2 (T-N = 30 K) and Er2ReC2 (T-N = 18 K) was monitored by temperature-dependent neutron diffraction up to the Neel temperatures of these carbides.