Heteroepitaxy and ferromagnetism of EuO/MgO (001): A route towards combined spin- and symmetry-filter tunneling

Abstract

We demonstrate the high-quality heteroepitaxy of ultrathin EuO films with bulklike ferromagnetism directly on MgO (001), an important step towards combining the spin-filter tunnel effect in magnetic insulators and symmetry-filter tunneling through single-crystalline MgO barriers. Despite a large compressive lattice mismatch, EuO grows fully relaxed on MgO (001) and adopts its bulk lattice parameter from the first monolayer on. This initial heteroepitaxial growth mode is discussed in terms of different electrostatic atomic configurations of the oxides interface. Single-crystalline EuO/MgO (001) thus can be envisioned as highly effective double spin-selective tunnel barriers for spintronics applications. © 2013 American Physical Society.