Cu_{2}O as nonmagnetic semiconductor for spin transport in crystalline oxide electronics

TL;DR

This study demonstrates that Cu_{2}O can support spin transport over nearly 100 nm in epitaxial heterostructures, highlighting its potential as a nonmagnetic semiconductor for spintronic oxide devices.

Contribution

First measurement of spin transport in Cu_{2}O showing a spin diffusion length of about 40 nm, indicating its suitability for spintronic applications.

Findings

Spin polarized carriers travel up to 100 nm in Cu_{2}O at low temperature.

Spin diffusion length estimated around 40 nm.

Insertion of SrTiO_{3} barrier does not enhance spin injection.

Abstract

We probe spin transport in Cu_{2}O by measuring spin valve effect in La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/Co and La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/La_{0.7}Sr_{0.3}MnO_{3} epitaxial heterostructures. In La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/Co systems we find that a fraction of out-of-equilibrium spin polarized carrier actually travel across the Cu_{2}O layer up to distances of almost 100 nm at low temperature. The corresponding spin diffusion length dspin is estimated around 40 nm. Furthermore, we find that the insertion of a SrTiO_{3} tunneling barrier does not improve spin injection, likely due to the matching of resistances at the interfaces. Our result on dspin may be likely improved, both in terms of Cu_{2}O crystalline quality and sub-micrometric morphology and in terms of device geometry, indicating that Cu_{2}O is a potential material for efficient spin transport in devices based on crystalline oxides.