Microscopic Investigation into the Electric Field Effect on Proximity-Induced Magnetism in Pt

Electric field effects on magnetism in metals have attracted widespread attention, but the microscopic mechanism is still controversial. We experimentally show the relevancy between the electric field effect on magnetism and on the electronic structure in Pt in a ferromagnetic state using element-specific measurements: x-ray magnetic circular dichroism (XMCD) and x-ray absorption spectroscopy (XAS). Electric fields are applied to the surface of ultrathin metallic Pt, in which a magnetic moment is induced by the ferromagnetic proximity effect resulting from a Co underlayer. XMCD and XAS measurements performed under the application of electric fields reveal that both the spin and orbital magnetic moments of Pt atoms are electrically modulated, which can be explained not only by the electric-field-induced shift of the Fermi level but also by the change in the orbital hybridizations.

Ab initio modelling of magnetic anisotropy in Sr3NiPtO6

First principles calculations in the framework of Density Functional Theory (DFT) and wavefunction-based correlated methods have been performed to investigate in detail the magnetic anisotropy in Sr3NiPtO6. This material is known for the easy-plane anisotropy with a large anisotropy constant of about 7.5-9.3 meV. We find that by properly choosing the onsite Coulomb repulsion and exchange parameters, DFT can correctly explain the easy-plane magnetocrystalline anisotropy of the material, but the magnitude of the anisotropy constant is underestimated. On the other hand, a quantitative agreement with respect to experiments, both in the magnitude and direction of the magnetic anisotropy, can be recovered by using the wavefunction-based approach which is able to fully describe the multiplet physics. We also show that the presence of structural distortions of the local NiO6 coordination is crucial for stabilizing the magnetic anisotropy in this compound.