Magnetization compensation and spin reorientation transition in ferrimagnetic DyCo₅: Multiscale modeling and element-specific measurements

Abstract

We use a multiscale approach linking ab initio calculations for the parametrization of an atomistic spin model with spin dynamics simulations based on the stochastic Landau-Lifshitz-Gilbert equation to investigate the thermal magnetic properties of the ferrimagnetic rare-earth transition-metal intermetallic DyCo5. Our theoretical findings are compared to elemental resolved measurements on DyCo5 thin films using the x-ray magnetic circular dichroism technique. With our model, we are able to accurately compute the complex temperature dependence of the magnetization. The simulations yield a Curie temperature of TC = 1030 K and a compensation point of Tcomp = 164 K, which is in a good agreement with our experimental result of Tcomp = 120 K. The spin reorientation transition is a consequence of competing elemental magnetocrystalline anisotropies in connection with different degrees of thermal demagnetization in the Dy and Co sublattices. Experimentally, we find this spin reorientation in a region from TSR1,2 = 320 to 360 K, whereas in our simulations the Co anisotropy appears to be underestimated, shifting the spin reorientation to higher temperatures.