Unidirectional Magnetoresistance in Antiferromagnet/Heavy-metal bilayers

Abstract

The interplay between electronic transport and antiferromagnetic order has attracted a surge of interest as recent studies have shown that a moderate change in the spin orientation of a collinear antiferromagnet may have a significant effect on the electronic band structure. Among numerous electrical probes to read out such magnetic order, unidirectional magnetoresistance (UMR), where the resistance changes under the reversal of the current direction, can provide rich insights into the transport properties of spin-orbit coupled systems. However, UMR has never been observed in antiferromagnets before, given the absence of intrinsic spin-dependent scattering. Here, we report a UMR in the antiferromagnetic phase of a FeRh$|$Pt bilayer, which undergoes a sign change and then increases strongly with an increasing external magnetic field, in contrast to UMRs in ferromagnetic and nonmagnetic systems. We show that Rashba spin-orbit coupling alone cannot explain the sizable UMR in the antiferromagnetic bilayer and that field-induced spin canting distorts the Fermi contours to greatly enhance the UMR by two orders of magnitude. Our results can motivate the growing field of antiferromagnetic spintronics, and suggest a route to the development of tunable antiferromagnet-based spintronics devices.

18 pages, 14 figures (5 figures in main text, 9 figures in supplemental material)

References in corpus (16)

• Writing and Reading antiferromagnetic Mn${}_2$Au: Néel spin-orbit torques and large anisotropic magnetoresistance
• Longitudinal Spin Seebeck Effect Free from the Proximity Nernst Effect
• Large Unidirectional Magnetoresistance in a Magnetic Topological Insulator
• Negative spin Hall magnetoresistance of Pt on the bulk easy-plane antiferromagnet NiO
• Optical determination of the Neel vector in a CuMnAs thin-film antiferromagnet
• Nonlinear planar Hall effect
• Nonlinear spin current generation in noncentrosymmetric spin-orbit coupled systems
• Theory of unidirectional spin Hall magnetoresistance in heavy-metal/ferromagnetic-metal bilayers
• Electrical detection of magnetization reversal without auxiliary magnets
• Perspective on Metallic Antiferromagnets
• Spin Seebeck effect in a polar antiferromagnet $\alpha$-Cu${}_2$V${}_2$O${}_7$
• Thickness dependence of unidirectional spin-Hall magnetoresistance in metallic bilayers
• Origin of threshold current density for asymmetric magnetoresistance in Pt/Py bilayers
• Large Rashba unidirectional magnetoresistance in the Fe/Ge(111) interface states
• Quantum Anomalous Hall Effect through Canted Antiferromagnetism
• Self-Consistent Local Mean-Field Theory for Phase Transitions and Magnetic Properties of FeRh

Cited by in corpus (8)

• Unidirectional Spin Hall Magnetoresistance in Antiferromagnetic Heterostructures
• Quantum kinetic theory of quadratic responses
• Engineering axion insulator phase in superlattices with inversion symmetry breaking
• Nonreciprocal Ballistic Transport in Asymmetric Bands
• Proximity-induced nonlinear magnetoresistances on topological insulators
• Theory of nonlinear magnetoelectric transport effects in normal-metal $-$ magnetic-insulator heterostructures
• Nonreciprocal ballistic transport in multi-layer Weyl semimetal films with surface engineering
• Asymmetric magnetoresistance in 3$d$-5$d$ based La${}_{0.67}$Ca${}_{0.33}$MnO${}_3$/SrIrO${}_3$ bilayer: The role of unidirectional anisotropy