The magnetic properties of a CeCoAl4 single crystal have been studied. In this compound, the Co atoms are non-magnetic and the Ce moments order antiferromagnetically below T-N = 13.5 K. From the temperature dependence of the reciprocal susceptibility in the paramagnetic region, a trivalent state of Ce is derived. The field dependence of the magnetisation at 4.2 K is strongly anisotropic. Along the c-axis, a spin-hop transition is observed at about 7.5 T. In fields as high as 20 T along the b and c-axes, the antiferromagnetism is broken, presumably resulting in almost aligned moments. Along the b-axis a field of 20 T does reorient the moments. The corresponding moments at 20 T along the b and c-axes are 1.11 mu(B)/Ce at. and 1.53 mu(B)/Ce at., respectively. The magnetic measurements are in good agreement with the results of the specific heat and magnetoresistance measurements. (C) 1998 Elsevier Science B.V. All rights reserved.
