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arXiv · 2012.14651

Giant anisotropic magnetoresistance with dual-four-fold symmetry in CaMnO3/CaIrO3 heterostructures

Suman Sardar·Megha Vagadia·Tejas Tank Sarmistha Das·Brandon Gunn·Parul Pandey·R. Hübner·Fanny Rodolakis·Gilberto Fabbris·Yongseong Choi·Daniel Haskel·Alex Frano·D. S. Rana
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Abstract

The realization of four-fold anisotropic magnetoresistance (AMR) in novel 3d-5d heterostructures has boosted major efforts in antiferromagnetic spintronics. However, despite the potential of incorporating strong spin-orbit coupling, only small AMR signals have been detected thus far, prompting a search for new mechanisms to enhance the signal. In this study on CaMnO3/CaIrO3 heterostructures, we report a unique dual-four-fold symmetric 70% AMR; a signal two orders of magnitude larger than previously observed in similar systems. We find that one order is enhanced by tuning a large biaxial anisotropy through octahedral tilts of similar sense in the constituent layers, while the second order is triggered by a spin-flop transition in a nearly Mott-type phase. Dynamics between these two phenomena as evidenced by the step-like AMR and a superimposed biaxial-anisotropy-induced AMR capture a subtle interplay of pseudospin coupling with the lattice and external magnetic field. Our study shows that a combination of charge-transfer, interlayer coupling, and a spin-flop transition can yield a giant AMR relevant for sensing and antiferromagnetic memory applications.

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Suman Sardar, Megha Vagadia, Tejas Tank Sarmistha Das, Brandon Gunn, Parul Pandey, R. Hübner, Fanny Rodolakis, Gilberto Fabbris, Yongseong Choi, Daniel Haskel, Alex Frano, D. S. Rana. 2020-12-29. Giant anisotropic magnetoresistance with dual-four-fold symmetry in CaMnO3/CaIrO3 heterostructures. https://arxiv.org/abs/2012.14651

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