Nanotechnology. 2017 Feb 24;28(8):08LT01. doi: 10.1088/1361-6528/aa56d4. Epub 2017 Jan 5.
Controlling magnetization using piezoelectric strain through the magnetoelectric effect offers several orders of magnitude reduction in energy consumption for spintronic applications. However strain is a uniaxial effect and, unlike directional magnetic field or spin-polarized current, cannot induce a full 180° reorientation of the magnetization vector when acting alone. We have engineered novel 'peanut' and 'cat-eye' shaped nanomagnets on piezoelectric substrates that undergo repeated deterministic 180° magnetization rotations in response to individual electric-field-induced strain pulses by breaking the uniaxial symmetry using shape anisotropy. This behavior can be likened to a magnetic ratchet, advancing magnetization clockwise with each piezostrain trigger. The results were validated using micromagnetics implemented in a multiphysics finite elements code to simulate the engineered spatial and temporal magnetic behavior. The engineering principles start from a target device function and proceed to the identification of shapes that produce the desired function. This approach opens a broad design space for next generation magnetoelectric spintronic devices.
通过磁电效应利用压电应变来控制磁化，可为自旋电子学应用降低几个数量级的能耗。然而，应变是单轴效应，与定向磁场或自旋极化电流不同，当单独作用时，它不能单独诱导磁化矢量的全 180°重新取向。我们在压电衬底上设计了新颖的“花生”和“猫眼”形状的纳米磁铁，通过使用形状各向异性打破单轴对称性，在单个电场感应应变脉冲的作用下，纳米磁铁经历重复的确定性 180°磁化旋转。这种行为类似于磁棘轮，每次压电力触发都会使磁化顺时针前进。使用多物理有限元代码中实现的磁动力学模拟了工程化的空间和时间磁行为，从而验证了结果。工程设计原则从目标器件功能开始，然后确定产生所需功能的形状。这种方法为下一代磁电自旋电子学器件开辟了广阔的设计空间。
