A strong ferroelectric ferromagnet created by means of spin-lattice coupling

June Hyuk Lee, Lei Fang, Eftihia Vlahos, Xianglin Ke, Young Woo Jung, Lena Fitting Kourkoutis, Jong Woo Kim, Philip J. Ryan, Tassilo Heeg, Martin Roeckerath, Veronica Goian, Margitta Bernhagen, Reinhard Uecker, P. Chris Hammel, Karin M. Rabe, Stanislav Kamba, Jürgen Schubert, John W. Freeland, David A. Muller, Craig J. FenniePeter Schiffer, Venkatraman Gopalan, Ezekiel Johnston-Halperin, Darrell G. Schlom

Research output: Contribution to journalArticle

500 Scopus citations

Abstract

Ferroelectric ferromagnets are exceedingly rare, fundamentally interesting multiferroic materials that could give rise to new technologies in which the low power and high speed of field-effect electronics are combined with the permanence and routability of voltage-controlled ferromagnetism. Furthermore, the properties of the few compounds that simultaneously exhibit these phenomena are insignificant in comparison with those of useful ferroelectrics or ferromagnets: their spontaneous polarizations or magnetizations are smaller by a factor of 1,000 or more. The same holds for magnetic- or electric-field-induced multiferroics. Owing to the weak properties of single-phase multiferroics, composite and multilayer approaches involving strain-coupled piezoelectric and magnetostrictive components are the closest to application today. Recently, however, a new route to ferroelectric ferromagnets was proposed by which magnetically ordered insulators that are neither ferroelectric nor ferromagnetic are transformed into ferroelectric ferromagnets using a single control parameter, strain. The system targeted, EuTiO 3, was predicted to exhibit strong ferromagnetism (spontaneous magnetization, ∼7 Bohr magnetons per Eu) and strong ferroelectricity (spontaneous polarization, ∼10μCcm-2) simultaneously under large biaxial compressive strain. These values are orders of magnitude higher than those of any known ferroelectric ferromagnet and rival the best materials that are solely ferroelectric or ferromagnetic. Hindered by the absence of an appropriate substrate to provide the desired compression we turned to tensile strain. Here we show both experimentally and theoretically the emergence of a multiferroic state under biaxial tension with the unexpected benefit that even lower strains are required, thereby allowing thicker high-quality crystalline films. This realization of a strong ferromagnetic ferroelectric points the way to high-temperature manifestations of this spin-lattice coupling mechanism. Our work demonstrates that a single experimental parameter, strain, simultaneously controls multiple order parameters and is a viable alternative tuning parameter to composition for creating multiferroics.

Original languageEnglish (US)
Pages (from-to)954-958
Number of pages5
JournalNature
Volume466
Issue number7309
DOIs
StatePublished - Aug 19 2010

All Science Journal Classification (ASJC) codes

  • General

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    Lee, J. H., Fang, L., Vlahos, E., Ke, X., Jung, Y. W., Kourkoutis, L. F., Kim, J. W., Ryan, P. J., Heeg, T., Roeckerath, M., Goian, V., Bernhagen, M., Uecker, R., Hammel, P. C., Rabe, K. M., Kamba, S., Schubert, J., Freeland, J. W., Muller, D. A., ... Schlom, D. G. (2010). A strong ferroelectric ferromagnet created by means of spin-lattice coupling. Nature, 466(7309), 954-958. https://doi.org/10.1038/nature09331