Giant spin-orbit torque in a single ferrimagnetic metal layer

Antiferromagnets and compensated ferrimagnets offer opportunities to investigate spin dynamics in the 'terahertz gap' because their resonance modes lie in the 0.3 THz to 3 THz range. Despite some inherent advantages when compared to ferromagnets, these materials have not been extensively s...

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Bibliographic Details
Published in:arXiv.org 2019-04
Main Authors: Lenne, Simon, Yong-Chang, Lau, Jha, Ajay, Gwenaël Y P Atcheson, Troncoso, Roberto E, Brataas, Arne, Coey, J M D, Stamenov, Plamen, Rode, Karsten
Format: Article
Language:English
Subjects:
Antiferromagnetism
Bilayers
Electron spin
Ferrimagnetism
Ferrimagnets
Ferromagnetism
Hall effect
Heavy metals
Information transfer
Monolayers
Nernst-Ettingshausen effect
Spin dynamics
Spintronics
Thin films
Torque
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Summary:Antiferromagnets and compensated ferrimagnets offer opportunities to investigate spin dynamics in the 'terahertz gap' because their resonance modes lie in the 0.3 THz to 3 THz range. Despite some inherent advantages when compared to ferromagnets, these materials have not been extensively studied due to difficulties in exciting and detecting the high-frequency spin dynamics, especially in thin films. Here we show that spin-obit torque in a single layer of the highly spin-polarized compensated ferrimagnet Mn2RuxGa is remarkably efficient at generating spin-orbit fields \mu_0H_eff, which approach 0.1x10-10 T m2/A in the low-current density limit -- almost a thousand times the Oersted field, and one to two orders of magnitude greater than the effective fields in heavy metal/ferromagnet bilayers. From an analysis of the harmonic Hall effect which takes account of the thermal contributions from the anomalous Nernst effect, we show that the antidamping component of the spin-orbit torque is sufficient to sustain self-oscillation. Our study demonstrates that spin electronics has the potential to underpin energy-frugal, chip-based solutions to the problem of ultra high-speed information transfer.
ISSN:2331-8422