Abstract:
The published data on the magnetic properties of strongly chained TlFeS$_2$ and TlFeSe$_2$ semiconductors have been analyzed. Based on this analysis, it is suggested that these semiconductors are quasi-one-dimensional antiferromagnets. Each of them has two Néel temperatures, which characterize the long-range $(T_{N3D})$ and short-range $(T_{N1D})$ magnetic orders.