Multiferroic heterostructures for spin filter application - an ab initio study

TL;DR

This study uses ab initio calculations to explore Fe/BaTiO3(001) as a multiferroic spin filter, demonstrating how electric polarization switching influences spin-dependent electron diffraction properties.

Contribution

It introduces a detailed theoretical analysis of multiferroic heterostructures for spin filtering, highlighting the control of spin scattering via electric polarization.

Findings

Polarization switching affects exchange and spin-orbit scattering.

The system enables electric field control of spin filtering.

Reflectivity and figure of merit are tunable by polarization.

Abstract

Novel imaging spin-filter techniques, which are based on low energy electron diffraction, are currently of high scientific interest. To improve the spin-detection efficiency a variety of new materials have been introduced in recent years. A new class of promising spin-filter materials are represented by multiferroic systems, as both magnetic and electric ordering exist in these materials. We have investigated Fe/BaTiO3(001), which defines a prominent candidate due to its moderate spontaneous polarization, for spin filter applications calculating diffraction patterns for spin polarized electrons incident on the Fe surface. Motivated by the fact that spin polarized low energy electron diffraction is a powerful method for the determination of the properties of surfaces we investigated the influence of switching the BaTiO3 polarization on the exchange and spin orbit scattering as well as on reflectivity and figure of merit. This system obviously offers the possibility to realize a multiferroic spin filter and manipulating the spin-orbit and exchange scattering by an external electric field. The calculations have been done for a large range of kinetic energies and polar angles of the diffracted electrons considering different numbers of Fe monolayers.