Bichalcogenide Model Systems for Magnetic Chains with Variable Spin Sizes and Optional Crystallographic Inversion Symmetry.

Abstract

To develop an understanding of the magnetism on one-dimensional lattices, one of the great challenges is to identify novel model systems with enough chemical flexibility to design the magnetic interactions in measurable samples. To contribute to this endeavor, we present a number of bichalcogenides with similar trigonal packing of magnetic chains. These chains consist of 3d transition-metal (TM) ions that are 6-fold-coordinated by S or Se. Each TM coordination can be described as a trigonally distorted octahedron that shares faces with two neighboring octahedra. A unique ability with these model systems is that an entity with electric polarity can be introduced between the chains that causes the TM ions in the chains to shift to polar positions, thereby allowing for magnetoelectric coupling. By a comparison of the macroscopic data of polar and nonpolar chains with either S = 1 or S = 3/2, it is obvious that the magnetic properties are affected by the indirect electric polarity from the entity between the chains.