Magnetoresistance of heavy and light metal/ferromagnet bilayers

Journal Article · Mon Nov 09 04:00:00 EST 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4935497· OSTI ID:22486053

Avci, Can Onur; Garello, Kevin; Mendil, Johannes; Ghosh, Abhijit; Blasakis, Nicolas; Gabureac, Mihai; Trassin, Morgan; Fiebig, Manfred; Gambardella, Pietro ^[1]

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1. Department of Materials, ETH Zürich, Hönggerbergring 64, CH-8093 Zürich (Switzerland)

We studied the magnetoresistance of normal metal (NM)/ferromagnet (FM) bilayers in the linear and nonlinear (current-dependent) regimes and compared it with the amplitude of the spin-orbit torques and thermally induced electric fields. Our experiments reveal that the magnetoresistance of the heavy NM/Co bilayers (NM = Ta, W, and Pt) is phenomenologically similar to the spin Hall magnetoresistance (SMR) of YIG/Pt, but has a much larger anisotropy of the order of 0.5%, which increases with the atomic number of the NM. This SMR-like behavior is absent in light NM/Co bilayers (NM = Ti and Cu), which present the standard anisotropic magnetoresistance expected from polycrystalline FM layers. In the Ta, W, and Pt/Co bilayers, we find an additional magnetoresistance directly proportional to the current and to the transverse component of the magnetization. This so-called unidirectional SMR, of the order of 0.005%, is largest in W and correlates with the amplitude of the antidamping spin-orbit torque. The unidirectional SMR is below the accuracy of our measurements in YIG/Pt.

• OSTI ID: 22486053
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 19 Vol. 107; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANISOTROPY
FERRITE GARNETS
IRON OXIDES
LAYERS
MAGNETORESISTANCE
METALS
NONLINEAR PROBLEMS
POLYCRYSTALS
SPIN
YTTRIUM COMPOUNDS