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

Abstract

In this paper, we present a detailed theoretical investigation of the electronic and magnetic properties of ferromagnetic slabs and clusters deposited on 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 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 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.

Schottky barrier formation at theFe/SrTiO3(001) interface: Influence of oxygen vacancies and layer oxidation

“…Our calculated Fe-O distance at the interface is in agreement with previously reported value of 1.961Å. 51 The oxygencation buckling, defined as ∆z = z(cation) − z(O) with z the coordinate along the [001] direction, is a quantity which can be related to the emergence of a local electric polarization. A slight buckling of ∆z = 4 × 10 −2Å is observed in the interface layer with the TiO 2 termination, and of ∆z = 2.5 × 10 −1Å for the SrO interface.…”

Non-monotonic magnetic anisotropy behavior as a function of adsorbate coverage in Fe ultrathin films near the spin reorientation transition

“…Orbital hybridization between C p orbitals and transition metal d orbitals has been reported to suppress negative contributions to K S , thus promoting PMA. 22,23 We suggest a similar effect is occurring in our system. On the contrary, top CO bonding must be enhancing positive contributions to K S .…”

Perpendicular magnetic anisotropy at transition metal/oxide interfaces and applications

“…This procedure is usually carried out using density functional theory based approaches which differ by the methods used to resolve Kohn-Sham equations as a function of choice of approximations for Hamiltonian (e.g., choice of external and exchange correlation potentials) and basis sets for wave functions (e.g., plane waves, local orbitals). Among methods employed in recent reports for MCA calculations in transition metal/oxide interfaces (Nakamura et al, 2010;Niranjan et al, 2010;Yang et al, 2011;Khoo et al, 2013;Suzuki et al, 2013;Kanai et al, 2014;Zhang et al, 2014;Bose et al, 2016;Li, Barreteau, and Smogunov, 2016) are full potential linearized augmented plane wave, full potential linear combination of atomic orbitals, screened Kohn-Korringa-Rostocker (sKKR), projector-augmented wave (PAW), or ultrasoft (US) pseudopotentials and others based on localized orbitals or plane waves basis set. For instance, the latter represents a natural choice for systems with periodic boundary conditions and is used in PAW and/or US pseudopotentials based on the Vienna ab initio simulation package (VASP) [see Blonski and Hafner (2009) and references therein] and the QUANTUM ESPRESSO (Giannozzi et al, 2009) package which are often used for efficient MCA calculations at transition metal/oxide interfaces.…”