Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
Nat Nanotechnol. 2012 Aug;7(8):499-503. doi: 10.1038/nnano.2012.111. Epub 2012 Jul 15.
The movement of magnetic domain walls can be used to build a device known as a shift register, which has applications in memory and logic circuits. However, the application of magnetic domain wall shift registers has been hindered by geometrical restrictions, by randomness in domain wall displacement and by the need for high current densities or rotating magnetic fields. Here, we propose a new approach in which the energy landscape experienced by the domain walls is engineered to favour a unidirectional ratchet-like propagation. The domain walls are defined between domains with an out-of-plane (perpendicular) magnetization, which allows us to route domain walls along arbitrary in-plane paths using a time-varying applied magnetic field with fixed orientation. In addition, this ratchet-like motion causes the domain walls to lock to discrete positions along these paths, which is useful for digital devices. As a proof-of-principle experiment we demonstrate the continuous propagation of two domain walls along a closed-loop path in a platinum/cobalt/platinum strip.
磁畴壁的运动可用于构建一种称为移位寄存器的器件，该器件在存储器和逻辑电路中有应用。然而，磁畴壁移位寄存器的应用受到几何限制、畴壁位移的随机性以及对高电流密度或旋转磁场的需求的阻碍。在这里，我们提出了一种新的方法，其中通过工程设计使畴壁经历的能量景观有利于单向棘轮式传播。畴壁在具有面外（垂直）磁化的畴之间定义，这允许我们使用具有固定方向的时变外加磁场沿着任意面内路径路由畴壁。此外，这种棘轮式运动导致畴壁锁定到这些路径上的离散位置，这对于数字设备很有用。作为原理验证实验，我们在铂/钴/铂条中演示了两个畴壁沿着闭环路径的连续传播。
