2D Metalorganic Ferromagnets

Low-dimensional materials exhibiting stable magnetic ordering are interesting from a fundamental point of view as well as for future application in information technologies. Metalorganic magnets, created by linking metal atoms with specific organic molecules, allow adjustments to their properties by synthetically modifying the structure of these molecules or the way they connect to the metal atoms. Here, the study details the formation, structure, and magnetic behavior of a single-layer 2D metalorganic coordination network made of Ni atoms and tetracyanoethylene (TCNE) molecules (2D Ni-TCNE). Single-layer crystal domains of this 2D material are achieved by codeposition Ni atoms and TCNE on a Au(111) surface kept in vacuum. Non-contact atomic force microscopy visualizes the structure with atomic resolution. X-ray magnetic circular dichroism establishes the 2D NiTCNE as a ferromagnet, with high magnetic remanence and a coercive field of ≈1 tesla at 3 kelvin. The Curie temperature is between 10 and 20 kelvin. Metalorganic chemistry opens a large variety of routes of synthesis and it is anticipated that this materials research paves the way to new magnetic nanomaterials for spintronic applications.