Title: Crystal and Magnetic Structures in Layered, Transition Metal Dihalides and Trihalides,
Abstract: Materials composed of two dimensional layers bonded to one another through
weak van der Waals interactions often exhibit strongly anisotropic behaviors
and can be cleaved into very thin specimens and sometimes into monolayer
crystals. Interest in such materials is driven by the study of low dimensional
physics and the design of functional heterostructures. Binary compounds with
the compositions MX2 and MX3 where M is a metal cation and X is a halogen anion
often form such structures. Magnetism can be incorporated by choosing a
transition metal with a partially filled d-shell for M, enabling ferroic
responses for enhanced functionality. Here a brief overview of binary
transition metal dihalides and trihalides is given, summarizing their
crystallographic properties and long-range-ordered magnetic structures,
focusing on those materials with layered crystal structures and partially
filled d-shells required for combining low dimensionality and cleavability with
magnetism.