We report on the determination of the spin Hall angle and the identification of the role of the interface roughness for the inverse spin Hall effect (ISHE) in ultra-clean, defect-reduced epitaxial Pt films. By applying vector network analyzer ferromagnetic resonance spectroscopy to a series of single crystalline Fe (12 nm) /Pt (tPt) bilayers we determine the real part of the spin mixing conductance (4.4±0.2)⋅1019m−2 and reveal a very small spin diffusion length in the epitaxial Pt (1.1±0.1) nm film. We investigate the spin pumping and ISHE in a stripe microstucture excited by a microwave coplanar waveguide (CPW) antenna. By using their different angular dependencies, we distinguish between spin rectification effects and the inverse spin Hall effect. The relatively large value of the spin Hall angle (5.7±1.4)% hints that interface engineering by epitaxially grown non-magnetic materials can increase the spin-to-charge current conversion efficiency.
@article{arxiv.1712.05334,
title = {Determination of the spin Hall angle in single-crystalline Pt films from spin pumping experiments},
author = {Sascha Keller and Laura Mihalceanu and Matthias R. Schweizer and Philipp Lang and Björn Heinz and Moritz Geilen and Thomas Brächer and Philipp Pirro and Thomas Meyer and Andres Conca and Dimitrios Karfaridis and George Vourlias and Thomas Kehagias and Burkard Hillebrands and Evangelos Th. Papaioannou},
journal= {arXiv preprint arXiv:1712.05334},
year = {2018}
}