Extraordinary anisotropic magnetoresistance in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>CaMn</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:mi>CaIr</mml:mi><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math> heterostructures
Megha Vagadia, Suman Sardar, Tejas M. Tank, Sarmistha Das, Brandon Gunn, Parul Pandey, René Hübner, Fanny Rodolakis, G. Fabbris, Yongseong Choi, D. Haskel, Alex Frañó, D. S. Rana
Abstract
The realization of fourfold anisotropic magnetoresistance (AMR) in $3d\ensuremath{-}5d$ heterostructures has boosted major efforts in antiferromagnetic (AFM) spintronics. However, despite the potential of incorporating strong spin-orbit coupling, only small AMR signals have been detected thus far, prompting a search for mechanisms to enhance the signal. In this paper, we demonstrate an extraordinarily elevated fourfold AMR of 70% realized in $\mathrm{CaMn}{\mathrm{O}}_{3}/\mathrm{CaIr}{\mathrm{O}}_{3}$ thin film superlattices. We find that the biaxial magnetic anisotropy and the spin-flop transition in a nearly Mott insulating phase form a potent combination, each contributing one order of magnitude to the total signal. Dynamics between these phenomena capture a subtle interaction of pseudospin coupling with the lattice and external magnetic field, an emergent phenomenon creating opportunities to harness its potential in AFM spintronics.