Magnetocrystalline anisotropy of Fe and Co slabs and clusters onSrTiO3by first-principles

In this paper, we present a detailed theoretical investigation of the electronic and magnetic properties of ferromagnetic slabs and clusters deposited on ${\mathrm{SrTiO}}₃$ via first-principles calculations, with a particular emphasis on the magnetocrystalline anisotropy (MCA). We found that in the case of Fe ultrathin films deposited on ${\mathrm{SrTiO}}₃$ the effect of the interface is to quench the MCA whereas for Co we observe a spin reorientation from in-plane to out-of-plane as compared to the free surface. We also find a strong enhancement of MCA for small clusters upon deposition on a ${\mathrm{SrTiO}}₃$ substrate. The origin of this enhancement of MCA is attributed to the hybridization between the substrate and the $d$ orbitals of the cluster extending in-plane for Fe and out-of-plane for Co. As a consequence, we predict that the Fe nanocrystals (even rather small) should be magnetically stable and are thus good potential candidates for magnetic storage devices.