SINGLE-CRYSTAL MAGNETIC-SUSCEPTIBILITY OF THE QUASI-ONE-DIMENSIONAL ANTIFERROMAGNET KFES2

The single crystal magnetic susceptibility of the quasi-one-dimensiona l antiferromagnet KFeS2 is reported. The high temperature isotropic su sceptibility is typical of a spin-1/2 Heisenberg chain. The intra- and interchain exchange constants are -44.7 K and 53.94 K, respectively. At 250 K, KFeS2 exhibits a well defined transition to a three-dimensio nally ordered antiferromagnetic state. The calculated perpendicular su sceptibility at OK considering the zero point reduction in magnetisati on for a S = 1/2 one-dimensional chain from spin wave theory is close to the projected value obtained from the experimental data. Copyright (C) 1997 Elsevier Science Ltd