MAGNETIC-PROPERTIES OF CSNICL3 AND RBNICL3

The magnetic moment and susceptibility of the linear-chain antiferromagnets CsNiCl3 and RbNiCl3 have been studied up to fields of 60 kG from 1.1 K to beyond their respective Néel temperatures. In both compounds clear evidence for a spin-flop transition near 20 kG has been obtained with the applied field parallel to the c-axis. Details of the magnetic phase diagram for CsNiCl3 have been clarified, particularly with respect to the spin reorientation which occurs near 4.4 K at low fields. No evidence has been obtained for the existence of a corresponding reorientation in RbNiCl 3.