Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 47: Spin Hall Effects and Skyrmions I

MA 47.12: Vortrag

Donnerstag, 23. März 2017, 12:30–12:45, HSZ 04

Tuning spin Hall angles by alloying — •S. Wimmer¹, K. Chadova¹, D. Ködderitzsch¹, M. Obstbaum², M. Decker², A. K. Greitner², M. Härtinger², T. N. G. Meier², M. Kronseder², C. H. Back², and H. Ebert¹ — ¹Department Chemie, Ludwig-Maximilians-Universität München — ²Institut für Experimentelle und Angewandte Physik, Universität Regensburg

Within a combined experimental and theoretical study it could be shown that the spin Hall angle of a substitutional alloy system can be continuously varied via its composition [1]. For Au_x Pt_1−x a substantial increase of the maximum spin Hall angle compared to the pure alloy partners could be achieved. The experimental findings for longitudinal charge conductivity σ_xx, transverse spin Hall conductivity σ_xy^z, and spin Hall angle α_SH could be confirmed by calculations based on the Kubo-Bastin formula [2] implemented in a KKR-CPA framework. Calculations of these response quantities for different temperatures using the so-called Alloy-Analogy Model [3] show that the divergent behavior of σ_xx and σ_xy^z is rapidly suppressed with increasing temperature T. As a consequence, σ_xy^z is dominated at higher T by its intrinsic contribution that has only a rather weak temperature dependence. Detailed analysis of the scaling behavior of σ_xy^z(x,T) w.r.t. σ_xx(x,T) moreover reveals that the extrinsic contribution changes sign as a function of T in the dilute limit x → 0.

[1] M. Obstbaum et al., Phys. Rev. Lett. 117, 167204 (2016). [2] A. Bastin et al., J. Phys. Chem. Solids 32, 1811 (1971). [3] H. Ebert et al., Phys. Rev. B 91, 165132 (2015).