Unidirectional spin Hall magnetoresistance in topological insulator/ferromagnetic layer heterostructures
arXiv:1701.06505 · doi:10.1038/s41467-017-02491-3
Abstract
The large spin orbit coupling in topological insulators results in helical spin-textured Dirac surface states that are attractive for topological spintronics. These states generate an efficient spin-orbit torque on proximal magnetic moments at room temperature. However, memory or logic spin devices based upon such switching require a non-optimal three terminal geometry, with two terminals for the writing current and one for reading the state of the device. An alternative two terminal device geometry is now possible by exploiting the recent discovery of a unidirectional spin Hall magnetoresistance in heavy metal/ferromagnet bilayers and (at low temperature) in magnetically doped topological insulator heterostructures. We report the observation of unidirectional spin Hall magnetoresistance in a technologically relevant device geometry that combines a topological insulator with a conventional ferromagnetic metal. Our devices show a figure-of-merit (magnetoresistance per current density per total resistance) that is comparable to the highest reported values in all-metal Ta/Co bilayers.
References in corpus (8)
- Universal Scaling Behavior of Anomalous Hall Effect and Anomalous Nernst Effect in Itinerant Ferromagnets
- Room temperature spin-orbit torque switching induced by a topological insulator
- Longitudinal Spin Seebeck Effect Free from the Proximity Nernst Effect
- Large Unidirectional Magnetoresistance in a Magnetic Topological Insulator
- Surface state dominated spin-charge current conversion in topological insulator/ferromagnetic insulator heterostructures
- Observation of inverse spin Hall effect in bismuth selenide
- Nanosecond-timescale low error switching of in-plane magnetic tunnel junctions through dynamic Oersted-field assisted spin-Hall effect
- Electrical detection of magnetization reversal without auxiliary magnets