Exceptionally high, strongly temperature dependent, spin Hall conductivity of SrRuO3

TL;DR

This study reveals that SrRuO3 exhibits an exceptionally high and temperature-dependent spin Hall conductivity, especially at low temperatures, highlighting its potential for advanced spintronics applications.

Contribution

The paper demonstrates the strong temperature dependence of spin Hall conductivity in SrRuO3 and introduces a new approach to studying spin-orbit interactions in oxide heterostructures.

Findings

Spin Hall conductivity in SrRuO3 reaches 3^5 9  at 60 K.

Below the ferromagnetic transition, non-standard SOT components emerge.

SrRuO3 shows promise for enhanced spintronics functionalities.

Abstract

Spin-orbit torques (SOT) in thin film heterostructures originate from strong spin-orbit interactions (SOI) that, in the bulk, generate a spin current as the result of extrinsic spin-dependent, skew or/and side-jump, scattering, or in the intrinsic case due to Berry curvature in the conduction band. While most SOT studies have focused on materials with heavy metal components, the oxide perovskite SrRuO3 has been predicted to have a pronounced Berry curvature. Through quantification of its spin current by the SOT exerted on an adjacent Co ferromagnetic layer, we determine that SrRuO3 has a strongly temperature (T) dependent spin Hall conductivity which becomes particularly high at low T, e.g. \sigma_{SH} \geqslant (\hbar/2e)3x10^{5} \Omega^{-1}m^{-1} at 60 K. Below the SrRuO3 ferromagnetic transition, non-standard SOT components develop associated with the magnetic characteristics of the oxide, but these do not dominate as with spin currents from a conventional ferromagnet. Our results establish a new approach for the study of SOI in epitaxial conducting oxide heterostructures and confirm SrRuO3 as a promising candidate material for achieving new and enhanced spintronics functionalities.