Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 32: Focus Session: Spin Current Devices

MA 32.2: Topical Talk

Thursday, March 14, 2013, 10:00–10:30, H10

Spin currents in ferromagnetic insulator/normal metal hybrids — •Matthias Althammer — Walther-Meißner-Institut, BAdW, Germany — University of Alabama, MINT Center, Tuscaloosa, USA

The controlled generation, manipulation, and detection of spin currents (i.e., of flows of spin angular momentum without an accompanying net flow of charge) - is the key to novel spin transport schemes and novel spintronic devices. We have experimentally investigated pure spin currents in ferromagnetic insulator/normal metal hybrid structures, using yttrium iron garnet, nickel ferrite, or magnetite for the magnetic insulator, and Pt, as well as Cu or Au, for the normal metal layer. On the one hand, we use spin pumping measurements to quantify the spin mixing conductance in our hybrid structures. On the other hand, we observe a novel magnetoresistive effect upon driving a conventional charge current through the Pt. This so-called spin Hall magnetoresistance (SMR) arises from the combined action of spin Hall and inverse spin Hall effect in Pt [1]. The SMR characteristically depends on the magnetization orientation in the magnetic insulator, although no electrical current flows through the latter. The SMR is qualitatively different from the anisotropic magnetoresistance effect arising in ferromagnetic metals, and in particular persists also when a thin Cu or Au layer is inserted between the magnetic insulator and the Pt layer. Taken together, the SMR thus represents a simple and powerful tool for the study of spin current transport in magnetic hybrid structures.

[1] H. Nakayama et al., arXiv 1211.0098.