Magnetization and specific heat of a ferromagnetic zigzag spin chain compound LaCrOS2

The magnetization and the specific heat of an oxysulfide LaCrOS2, in which Cr ions form zigzag spin chains, have been measured. The temperature dependence of the magnetic susceptibility deviates from the Curie–Weiss behavior with the Weiss temperature Θp=66 K, below 200 K. A peak appears in the low field susceptibility vs. temperature curve at 32 K, which is regarded to signal the ferromagnetic transition. The temperature dependence of the magnetic specific heat shows a broad maximum, which is characteristic of a low dimensional magnetic system. In addition, a small sharp peak is observed at 32 K which is attributed to the three-dimensional ferromagnetic transition. These behaviors are well explained by an effective Ising spin chain model for S=3/2 with a weak interchain interaction.