Control of spin current by a magnetic YIG substrate in NiFe/Al nonlocal spin valves

F. Dejene (1, 2) , N. Vlietstra (2) , D. Luc (3) , Xavier Waintal (3, 4) , J. Ben Youssef (5) , J. van Wees (2)

1 Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials
2 Zernike Institute for Advanced Materials
3 SPSMS - UMR 9001 - Service de Physique Statistique, Magnétisme et Supraconductivité
4 GT - Laboratory of Quantum Theory
5 LMB - Laboratoire de magnétisme de Bretagne

We study the effect of a magnetic insulator [yttrium iron garnet (YIG)] substrate on the spin-transport properties of Ni80Fe20/Al nonlocal spin valve (NLSV) devices. The NLSV signal on the YIG substrate is about two to three times lower than that on a nonmagnetic SiO2 substrate, indicating that a significant fraction of the spin current is absorbed at the Al/YIG interface. By measuring the NLSV signal for varying injector-to-detector distances and using a three-dimensional spin-transport model that takes spin-current absorption at the Al/YIG interface into account, we obtain an effective spin-mixing conductance G(up arrow down arrow) similar or equal to 5-8 x 10(13) Omega(-1) m(-2). We also observe a small, but clear, modulation of the NLSV signal when rotating the YIG magnetization direction with respect to the fixed spin polarization of the spin accumulation in the Al. Spin relaxation due to thermal magnons or roughness of the YIG surface may be responsible for the observed small modulation of the NLSV signal.

Mots clés: Accumulation

Domaines: Physique [physics]

F. Dejene, N. Vlietstra, D. Luc, Xavier Waintal, J. Ben Youssef, et al.. Control of spin current by a magnetic YIG substrate in NiFe/Al nonlocal spin valves. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2015, 91 (10), pp.100404. ⟨10.1103/PhysRevB.91.100404⟩. ⟨hal-02007823⟩