Recent research in spintronics to develop efficient devices using spin currents has focused on magnetic insulators. Yttrium iron garnet (YIG) is a ferrimagnetic insulator with properties that make it ideal for use in spin pumping, spin transfer torque and spin Hall magnetoresistance measurements and applications. Spin currents can propagate over relatively long distances in YIG making it an ideal material for the emerging field of magnonics, where spin wave excitations can be exploited to transfer and process information in nanostructures. Unusual, and undesirable, magnetic behaviour is observed in thin films (<100nm) which also varies with temperature. The origin of this behaviour has remained elusive. A team of researchers, led by the University of Leeds, have used a variety of techniques to study the structural and magnetic properties of single crystal thin-film YIG. Polarised neutron reflectivity (PNR) measurements performed on the Polref beamline have spatially resolved the magnetic profile of the layer to reveal an interdiffused region with magnetic and temperature dependent properties distinct to the bulk of the film. These results are of direct relevance to the large body of research in insulator-based magnonics.
Related publication: A. Mitra et al. “Interfacial Origin of the Magnetisation Suppression of Thin Film Yttrium Iron Garnet" Scientific Reports 7(2017), 11774, DOI: 10.1038/s41598-017-10281-6