Naval Research Laboratory, Washington, DC 20375, USA.
Nano Lett. 2010 Apr 14;10(4):1219-23. doi: 10.1021/nl9036406.
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(0.7)Ga(0.3)/BaTiO(3) 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 approximately 7-11 MV/m electric fields to the piezoelectric BaTiO(3) film, local magnetic domains rearrange in the ferromagnetic Fe(0.7)Ga(0.3) layer due to the transfer of strain from the BaTiO(3) film. A simulation based on micromagnetic modeling shows a magnetostrictive anisotropy of 25 kPa induced in the Fe(0.7)Ga(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.
我们报告了在洛伦兹显微镜原位观察中使用静态（直流）电场对磁畴进行控制和可逆切换的直接观察。通过从生长衬底机械释放的薄膜 Fe(0.7)Ga(0.3)/BaTiO(3) 双层结构中的机电耦合来实现切换。畴壁运动被动态观察，允许在整个施加电场范围内直接关联局部磁序。在向压电 BaTiO(3) 薄膜施加约 7-11 MV/m 的电场时，由于 BaTiO(3) 薄膜的应变传递，铁磁 Fe(0.7)Ga(0.3)层中的局部磁畴重新排列。基于微磁模拟的模拟表明，由于应变，Fe(0.7)Ga(0.3)中产生了 25 kPa 的磁致伸缩各向异性。这种电场依赖性的单轴各向异性被提出作为控制集成磁电存储节点操作期间矫顽场的可能机制。
