Unidirectional spin Hall magnetoresistance in ferromagnet/normal metal bilayers

By C. Avci, Kevin Garello, Abhijit Ghosh, M. Gabureac, S. Alvarado, Pietro Gambardella. Nature Physics, 2015

407 citations recorded by the source corpus.

Magnetoresistive effects are usually invariant on inversion of the magnetization direction. In non-centrosymmetric conductors, however, nonlinear resistive terms can give rise to a current dependence that is quadratic in the applied voltage and linear in the magnetization. Here we demonstrate that such conditions are realized in simple bilayer metal films where the spin–orbit interaction and spin-dependent scattering couple the current-induced spin accumulation to the electrical conductivity. We show that the longitudinal resistance of Ta|Co and Pt|Co bilayers changes when reversing the polarity of the current or the sign of the magnetization. This unidirectional magnetoresistance scales linearly with current density and has opposite sign in Ta and Pt, which we associate with the modification of the interface scattering potential induced by the spin Hall effect in these materials. Our results suggest a route to control the resistance and detect magnetization switching in spintronic devices using a two-terminal geometry, which applies also to heterostructures including topological insulators. A unidirectional magnetoresistance observed in bilayer metal films could be used to add directional sensitivity to conventional magnetic sensors based on anisotropic magnetoresistance.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/d036e1fb2db05c52f098374440804732b239d09c

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

1. Pietro Gambardella
2. J. Sinova
3. T. Jungwirth
4. A. Manchon
5. G. Sala
6. I. Miron
7. Kevin Garello
8. A. Thiaville

In Electrical and Electronic Engineering

1. J. Sinova
2. A. Manchon
3. T. Jungwirth
4. A. Thiaville
5. Kevin Garello
6. Pietro Gambardella
7. I. Miron
8. J. Železný

Citations in the corpus

• Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems (2018, methodology): “The SOTs are typically large in high resistivity metals and correlate with the presence of strong SMR in FM/NM layers (Nakayama et al., 2013) and crystalline AMR in FM/semiconductor layers.”
• Giant orbital Hall effect and orbital-to-spin conversion in 3d, 5d, and 4f metallic heterostructures (2022, result): “(xii) Orbital accumulation might also give rise to a unidirectional magnetoresistance, in analogy to the unidirectional spin Hall magnetoresistance [45].”
• Spin insulatronics (2020, unknown): “as the uniaxial magneto-resistance [178].”