Giant electrostatic modification of magnetism via electrolyte-gate-induced cluster percolation in La1−xSrxCoO3−δ

Walter, Jeff
Orth, Peter
Charlton, T.
Ambaye, H.
Fitzsimmons, M. R.
Orth, Peter
Fernandes, R. M.
Leighton, Chris
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Orth, Peter
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Ames Laboratory
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Physics and Astronomy
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Electrical control of magnetism is a long-standing goal in science and technology, with the potential to enable a next generation of low-power memory and logic devices. Recently developed electrolyte gating techniques provide a promising route to realization, although the ultimate limits on modulation of magnetic properties remain unknown. Here, guided by a recent theoretical prediction, we demonstrate large enhancement of electrostatic modulation of ferromagnetic order in ion-gel-gated ultrathin films of the perovskite La0.5Sr0.5CoO3−δ by thickness tuning to the brink of percolation. Application of only 3–4 V is then shown capable of inducing a clear percolation transition from a short-range magnetically ordered insulator to a robust long-range ferromagnetic metal with perpendicular magnetic anisotropy. This realizes giant electrostatic Curie temperature modulation over a 150 K window, outstanding values for both complex oxides and electrolyte gating. In operando polarized neutron reflectometry confirms gate-controlled ferromagnetism, additionally demonstrating, surprisingly, that electrostatically induced magnetic order can penetrate substantially deeper than the Thomas-Fermi screening length.

<p>This article is published as Walter, Jeff, T. Charlton, H. Ambaye, M. R. Fitzsimmons, Peter P. Orth, R. M. Fernandes, and Chris Leighton. "Giant electrostatic modification of magnetism via electrolyte-gate-induced cluster percolation in La1−xSrxCoO3−δ." <em>Physical Review Materials</em> 2, no. 11 (2018): 111406. DOI: <a href="" target="_blank">10.1103/PhysRevMaterials.2.111406</a>. Posted with permission.</p>