University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Friday, October 6th 2017
12:20 pm:
Speaker: Justin Watts, University of Minnesota
Subject: Elliott-Yafet Scaling of Spin Lifetimes in Al and Cu Non-Local Spin Valves

Spin relaxation in metals is often discussed within the framework of Elliott-Yafet (EY) relaxation, where the spin relaxation and elastic scattering rates are related via a proportionality constant referred to as the EY parameter. Although this parameter is known for some scattering sources (e.g., phonons) in certain elemental metals, experimental knowledge and general understanding remains limited. Here, we significantly expand the experimental knowledge base by determining EY phonon and defect parameters in Al and Cu non-local spin valves with channel thicknesses from 400 to 20 nm. For Al we find a surprisingly broad range for the phonon parameter which contrasts with expectations of a constant value for a specified material. In particular, we find an unexpected size dependence that is discussed in terms of finite size effects and the Debye temperature.These results identify factors limiting metallic spin diffusion lengths and hence the performance of nanoscopic spin transport devices.

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