Experimentally realizable devices for domain wall motion control
Experimentally realizable devices for domain wall motion control
复制标题
用于畴壁运动控制的实验可实现装置
DOI：
10.1088/1367-2630/7/1/082
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发表时间：
2005
影响因子：
3.3
通讯作者：
F. Nori
中科院分区：
文献类型：
--
作者：
S. Savel'ev;A. Rakhmanov;F. Nori
磁畴壁 (MDW) 在外加磁场的驱动下可以移动。这种运动对于许多设备都很重要，包括磁记录读/写头、变压器和磁传感器。具有锯齿轮廓的磁性薄膜将 MDW 定位在薄膜最窄部分的离散位置。我们提出了一种通过施加磁场脉冲在这些离散位置之间移动这些畴壁的可控方法。在我们的建议中，每个施加的磁脉冲都可以为 MDW 产生增量或步进运动。这可以用作移位寄存器。附着在薄膜一端的大型磁性元件上的类似图案的磁性薄膜充当异或逻辑门。当由交流磁场驱动时，不对称锯齿轮廓可用作棘轮，从而产生振荡或运行 MDW 运动。在将这两个动态状态（振荡和运行 MDW）分开的阈值驱动（双稳态点）附近，以外部磁场的非常弱振荡编码的微弱信号极大地改变了速度谱，极大地放大了混合谐波。这种效应可用于放大或移动微弱信号的频率。
Magnetic domain walls (MDWs) can move when driven by an applied magnetic field. This motion is important for numerous devices, including magnetic recording read/write heads, transformers and magnetic sensors. A magnetic film, with a sawtooth profile, localizes MDWs in discrete positions at the narrowest parts of the film. We propose a controllable way to move these domain walls between these discrete locations by applying magnetic field pulses. In our proposal, each applied magnetic pulse can produce an increment or step-motion for an MDW. This could be used as a shift register. A similarly patterned magnetic film attached to a large magnetic element at one end of the film operates as an XOR logic gate. The asymmetric sawtooth profile can be used as a ratchet resulting in either oscillating or running MDW motion, when driven by an ac magnetic field. Near a threshold drive (bistable point) separating these two dynamical regimes (oscillating and running MDW), a weak signal encoded in very weak oscillations of the external magnetic field drastically changes the velocity spectrum, greatly amplifying the mixing harmonics. This effect can be used either to amplify or shift the frequency of a weak signal.