Spin transport and spin dephasing in zinc oxide

TL;DR

This study investigates spin transport and dephasing in zinc oxide using vertical spin valve devices, revealing temperature-dependent spin diffusion lengths and lifetimes crucial for spintronic applications.

Contribution

It provides experimental measurements of spin diffusion lengths and lifetimes in ZnO, demonstrating the material's potential for spintronics due to its small spin-orbit coupling.

Findings

Spin diffusion lengths of ~10.8nm at 2K and ~6.2nm at 200K.

Spin lifetimes of 2.6ns at 2K and 31ps at 200K.

Magnetoresistance data aligns with a two spin channel model.

Abstract

The wide bandgap semiconductor ZnO is interesting for spintronic applications because of its small spin-orbit coupling implying a large spin coherence length. Utilizing vertical spin valve devices with ferromagnetic electrodes (TiN/Co/ZnO/Ni/Au), we study the spin-polarized transport across ZnO in all-electrical experiments. The measured magnetoresistance agrees well with the prediction of a two spin channel model with spin-dependent interface resistance. Fitting the data yields spin diffusion lengths of 10.8nm (2K), 10.7nm (10K), and 6.2nm (200K) in ZnO, corresponding to spin lifetimes of 2.6ns (2K), 2.0ns (10K), and 31ps (200K).