Ralph Skomski

Magnetically Ordered Transition-Metal-Intercalated WSe2

Introducing magnetic behavior in nonmagnetic transition metal dichalcogenides is essential to broaden their applications in spintronic and nanomagnetic devices. In this article, we investigate the electronic and magnetic properties of transition-metal-intercalated tungsten diselenide (WSe2) using density functional theory. We find that intercalation compounds with composition of T1/4WSe2 (T is an iron-series transition-metal atom) exhibit substantial magnetic moments and pronounced ferromagnetic order for late transition metals. The densities of states of the T atoms and the magnetic moments on the W sites indicate that the moments of the intercalated atoms become more localized with increasing atomic number. A large perpendicular magnetocrystalline anisotropy of about 9 meV per supercell has been found for Fe1/4WSe2. Furthermore, using mean field theory, we estimated high Curie temperatures of 660, 475, and 379 K for Cr, Mn, and Fe, respectively. The predicted magnetic properties suggest that WSe2 may have applications in spin electronics and nanomagnetic devices.

Exchange coupling and spin structure in cobalt-on-chromia thin films

Cobalt-chromia interface exchange interactions in the Co-on-Cr2O3(0001) system are investigated. Density-functional theory predicts the exchange coupling at the interface to be antiferromagnetic, in agreement with earlier experimental results. The spin-polarized photoemission spectra reveal both perpendicular and in-plane magnetization components, in the cobalt adlayer on chromia. A magnetization canted with respect to the surface normal, inferred from the presence of remnant spin polarization both in the plane of the cobalt film and along the surface normal may be understood as a micromagnetic canting effect involving magnetostatic self-interaction and exchange coupling between Co and Cr2O3.