Full oxide heterostructure combining a high-Tc diluted ferromagnet with a high-mobility conductor

TL;DR

This paper demonstrates the growth of oxide heterostructures combining a high-Tc ferromagnet with a high-mobility conductor, revealing significant spin polarization and quantum oscillations, opening avenues for spintronic applications.

Contribution

It introduces a novel oxide heterostructure integrating a high-Curie temperature ferromagnet with a high-mobility conductor, analyzing its electronic and spin transport properties.

Findings

Large spin polarization in Co-LSTO observed.

High electronic mobility (~10,000 cm²/Vs) at 10 K.

Detection of Shubnikov-de Haas oscillations indicating quantum coherence.

Abstract

We report on the growth of heterostructures composed of layers of the high-Curie temperature ferromagnet Co-doped (La,Sr)TiO3 (Co-LSTO) with high-mobility SrTiO3 (STO) substrates processed at low oxygen pressure. While perpendicular spin-dependent transport measurements in STO//Co-LSTO/LAO/Co tunnel junctions demonstrate the existence of a large spin polarization in Co-LSTO, planar magnetotransport experiments on STO//Co-LSTO samples evidence electronic mobilities as high as 10000 cm2/Vs at T = 10 K. At high enough applied fields and low enough temperatures (H < 60 kOe, T < 4 K) Shubnikov-de Haas oscillations are also observed. We present an extensive analysis of these quantum oscillations and relate them with the electronic properties of STO, for which we find large scattering rates up to ~ 10 ps. Thus, this work opens up the possibility to inject a spin-polarized current from a high-Curie temperature diluted oxide into an isostructural system with high-mobility and a large spin diffusion length.