Tunable magnetization relaxation of Fe_{2}Cr_{1-x}Co_{x}Si half-metallic Heusler alloys by band structure engineering

摘要

We report a systematic investigation on the magnetization relaxationproperties of iron-based half-metallic Heusler alloyFe$_{2}$Cr$_{1-x}$Co_${x}$Si (FCCS) thin films using broadband angular-resolvedferromagnetic resonance. Band structure engineering through Co doping (x)demonstrated by first-principles calculations is shown to tune the intrinsicmagnetic damping over an order of magnitude, namely 0.01-0.0008. Notably, theintrinsic damping constants for samples with high Co concentration are amongthe lowest reported for Heusler alloys and even comparable to magneticinsulator yttrium iron garnet. Furthermore, a significant reduction of bothisotropic and anisotropic contributions of extrinsic damping of the FCCS alloyswas found in the FCCS films with x=0.5-0.75, which is of particular importancefor applications. These results demonstrate a practical recipe to tailorfunctional magnetization for Heusler alloy-based spintronics at roomtemperature