Experimental Verification of Comparability between Spin-Orbit and Spin-Diffusion Lengths

TL;DR

This study experimentally confirms that spin-orbit lengths and spin diffusion lengths in noble metals are comparable, validating different measurement techniques and supporting the Elliott-Yafet mechanism's dominance in spin transport.

Contribution

It provides the first direct experimental comparison between spin-orbit and spin diffusion lengths across various metals, including those with strong spin-orbit interactions.

Findings

Spin-orbit lengths from weak anti-localization measurements are comparable to spin diffusion lengths from lateral spin valves.

Both lengths are much larger than values from spin torque ferromagnetic resonance.

Disorder dependence of copper's spin-orbit length follows a linear law, indicating Elliott-Yafet mechanism dominance.

Abstract

We experimentally confirmed that the spin-orbit lengths of noble metals obtained from weak anti-localization measurements are comparable to the spin diffusion lengths determined from lateral spin valve ones. Even for metals with strong spin-orbit interactions such as Pt, we verified that the two methods gave comparable values which were much larger than those obtained from recent spin torque ferromagnetic resonance measurements. To give a further evidence for the comparability between the two length scales, we measured the disorder dependence of the spin-orbit length of copper by changing the thickness of the wire. The obtained spin-orbit length nicely follows a linear law as a function of the diffusion coefficient, clearly indicating that the Elliott-Yafet mechanism is dominant as in the case of the spin diffusion length.