Search for: All records

Abstract We study the magneto-optical properties of Fe–Co–Al ordered alloys in the terahertz range of frequencies. Using the standard Kubo-based approach to compute intrinsic part of the ${\sigma }_{xy}\left(\omega \right)$we find a strong dependence ofσ_xyonωin the terahertz range. For example, we find that below 10 THz Co₃Al has nearly constantσ_xyand that above 10 THz it is reduced by about 50 times. Furthermore, we find a strong dependence ofσ_xyon the chemical composition. For example, we find that the addition of Al to Fe changes the sign ofσ_xy, while the addition of Co to Fe leads to a nonmonotonic dependence ofσ_xyon Co concentration. 

WfBase is a software package providing an easy way to compute from first-principles various properties depending on the electronic structure of periodic solids. This package can parse user-provided mathematical expressions, in a human-readable format, using the Einstein notation for indices. This package also comes with a built-in database of some simple materials. For more details, please see:  https://coh.ucr.edu/wfbase 

We have investigated the electrical transport properties of nanodevices fabricated from exfoliated flakes of two-dimensional metallic ferromagnets Fe3GeTe2 (FGT) and Fe5Ge2Te2 (FG2T) down to below three layers in thickness. The per-layer anomalous Hall conductivity even in thick FGT and FG2T devices is found to be much smaller than ∼e2h, the approximate value calculated for thick undoped crystals. Moreover, we obtain a power-law scaling relation between the per-layer anomalous Hall and per-layer longitudinal conductivities with an exponent close to 1.6, which agrees with the universal value for poor ferromagnetic conductors. Both FGT and FG2T devices show clear layer-dependent Curie temperatures and layer-dependent perpendicular magnetic anisotropy, with FG2T dominating the former and FGT dominating the latter for all thicknesses. Despite their declining trend as the device thickness decreases, both Curie temperature and magnetic anisotropy retain a significant fraction of their bulk values (>60% and >80% of the bulk values, respectively, even in the thinnest FG2T device), indicating attractive potential for practical applications.