Thin-film oxide heterostructures show great potential for use in spintronic memories, where electronic charge and spin are coupled to transport information. Here we use a La 0.7 Sr 0.3 MnO 3 (LSMO)/PbZr 0.2 Ti 0.8 O 3 (PZT) model system to explore how local variations in electronic and magnetic phases mediate this coupling. We present direct, local measurements of valence, ferroelectric polarization and magnetization, from which we map the phases at the LSMO/PZT interface. We combine these experimental results with electronic structure calculations to elucidate the microscopic interactions governing the interfacial response of this system. We observe a magnetic asymmetry at the LSMO/PZT interface that depends on the local PZT polarization and gives rise to gradients in local magnetic moments; this is associated with a metal-insulator transition at the interface, which results in significantly different charge-transfer screening lengths. This study establishes a framework to understand the fundamental asymmetries of magnetoelectric coupling in oxide heterostructures
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S.R.S. and M.L.T. thank Steven May, Eun Ju Moon, Rebecca Sichel-Tissot and Brian Kirby for constructive discussions. S.R.S also thanks Jennifer D. Sloppy, Christopher R. Winkler and Michael L. Jablonski for their assistance with TEM sample preparation. We acknowledge the support from the National Science Foundation under grants #CMMI-1031403 (M.L.T. and S.R.S.), #ENG-1434147 (J.K.), #DMR-1451219 (L.W.M.), as well as from the Office of Naval Research under grants #N00014-1110-296 and #N00014-1410-058 (M.L.T. and S.R.S). A.R.D. acknowledges support from the Army Research Office under grant #W911NF-14-1-0104. P.V.B. and J.M.R. were supported by the Defense Advanced Research Projects Agency under grant #N66001-12-4224 and the Army Research Office under W911NF-15-1-0017. L.J. acknowledges the support from the European Union Seventh Framework Programme under Grant Agreement 312483—ESTEEM2 (Integrated Infrastructure Initiative I3). DFT calculations were performed with the Department of Defense Garnet ERDC machine. Electron microscopy was conducted in Drexel University’s Centralized Research Facilities. Additional electron microscopy was carried out at SuperSTEM, the U.K. National Facility for Aberration-Corrected STEM supported by the UK Engineering and Physical Sciences Research Council. Neutron experiments were carried out at the Spallation Neutron Source, which is sponsored by the Division of Scientific User Facilities, Office of Basic Energy Sciences, US Department of Energy, under contract DE-AC05-00OR22725 with UT-Battelle, LLC. We gratefully acknowledge the technical assistance for PNR experiments from R. J. Goyette; Jr author S.R.S. was supported by a Department of Defense National Defense Science and Engineering Graduate (NDSEG) Fellowship.