Magnetic properties of a quaternary iron sulfide BaLa2FeS5

The magnetic properties of a quaternary iron sulfide BaLa2FeS5 have been in vestigated through AC and DC magnetic susceptibility and specific measureme nts. The effective magnetic moment of the Fe ion was found to be 5.41 muB i n the temperature range where the Curie-Weiss law holds good. This result i ndicates that the divalent Fe ions are in a high-spin (S = 2) state. The ze ro-field-cooled condition (ZFC) magnetic susceptibilities have a maximum at 22 K and decrease with decreasing temperature, while the field-cooled cond ition (FC) susceptibilities are nearly constant below 22 K. The magnetic sp ecific heat has a broad maximum at 28 K. In the AC magnetic susceptibilitie s, single maxima of chi' and chi " are observed at around 25 K. The frequen cy dependence of the corresponding peak temperatures of BaLa2FeS5 can be de scribed as a thermally activated process for spin-glasses. (C) 2001 Elsevie r Science Ltd. All rights reserved.