Structural sensitivity of the spin Hall magnetoresistance in antiferromagnetic thin films

Reading the magnetic state of antiferromagnetic (AFM) thin films is key for AFM spintronic devices. We investigate the underlying physics behind the spin Hall magnetoresistance (SMR) of bilayers of platinum and insulating AFM hematite (α-Fe2O3) and find an SMR efficiency of up to 0.1%, comparable to ferromagnetic-based structures. To understand the observed complex SMR field dependence, we analyze the effect of misalignments of the magnetic axis that arise during growth of thin films, by electrical measurements and direct magnetic imaging, and find that a small deviation can result in significant signatures in the SMR response. This highlights the care that must be taken when interpreting SMR measurements on AFM spin textures.

Citation

Ross, A., Lebrun, R., Ulloa, C., Grave, D. A., Kay, A., Baldrati, L., … Kläui, M. (2020). Structural sensitivity of the spin Hall magnetoresistance in antiferromagnetic thin films. Physical Review B, 102(9). doi:10.1103/physrevb.102.094415

Sponsors

A. Ross and M.K. acknowledge support from the Graduate School of Excellence Materials Science in Mainz (Grant No.DFG/GSC 266). This work was supported by the Max Planck Graduate Center with the Johannes Gutenberg-Universität Mainz (MPGC). A. Ross, R.L., and M.K. acknowledge support from the DFG Projects No. 423441604 and No. 403502522. R.L. acknowledges the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement FAST No. 752195. All authors from Mainz also acknowledge support from both MaHoJeRo (DAAD Spintronics network, Project No. 57334897), SPIN+X (DFG SFB TRR 173, Project No. A01) and KAUST (Grant No. OSR-2019-CRG8-4048.2). D.A.G., A.K., and A.Rothschild acknowledge support from the European Research Council under the European Union’s Seventh Framework programme (Grant No. FP/200702013)/ERC (Grant Agreement No. 617516). D.A.G. acknowledges support from The Center for Absorption in Science, Ministry of Immigrant Absorption, State of Israel. The work including the Mainz-Utrecht collaboration was also supported by the Research Council of Norway through its Centres of Excellence funding scheme, Project No. 262633 “QuSpin.” C.U. acknowledges support from the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO). L.B. acknowledges the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement ARTES No. 793159. Magnetic domain imaging measurements were carried out at the PEEM instrument of the UE49-PGMa beamline at Helmholtz-Zentrum Berlin für Materialien und Energie. We thankfully acknowledge the financial support from HZB under Proposal No. 182-07628 ST.