In Situ Observation of Reversible Nanomagnetic Switching Induced by Electric Fields

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• 作者：Todd Brintlinger ; Sung-Hwan Lim ; Kamal H. Baloch ; Paris Alexander ; Yi Qi ; John Barry ; John Melngailis ; Lourdes Salamanca-Riba ; I. Takeuchi ; John Cumings
• 刊名：Nano Letters
• 出版年：2010
• 出版时间：April 14, 2010
• 年：2010
• 卷：10
• 期：4
• 页码：1219-1223
• 全文大小：285K
• 年卷期：v.10,no.4(April 14, 2010)
• ISSN：1530-6992

文摘

We report direct observation of controlled and reversible switching of magnetic domains using static (dc) electric fields applied in situ during Lorentz microscopy. The switching is realized through electromechanical coupling in thin film Fe_0.7Ga_0.3/BaTiO₃ bilayer structures mechanically released from the growth substrate. The domain wall motion is observed dynamically, allowing the direct association of local magnetic ordering throughout a range of applied electric fields. During application of 7−11 MV/m electric fields to the piezoelectric BaTiO₃ film, local magnetic domains rearrange in the ferromagnetic Fe_0.7Ga_0.3 layer due to the transfer of strain from the BaTiO₃ film. A simulation based on micromagnetic modeling shows a magnetostrictive anisotropy of 25 kPa induced in the Fe_0.7Ga_0.3 due to the strain. This electric-field-dependent uniaxial anisotropy is proposed as a possible mechanism to control the coercive field during operation of an integrated magnetoelectric memory node.