Proenca M P, Muñoz M, Villaverde I, Migliorini A, Raposo V, Lopez-Diaz L, Martinez E, Prieto J L
Instituto de Sistemas Optoelectrónicos y Microtecnología (ISOM), Universidad Politécnica de Madrid, Avda. Complutense 30, E-28040, Madrid, Spain.
IFIMUP and IN-Institute of Nanoscience and Nanotechnology and Dep. Física e Astronomia, Universidade do Porto, Rua do Campo Alegre 687, 4169-007, Porto, Portugal.
Sci Rep. 2019 Nov 22;9(1):17339. doi: 10.1038/s41598-019-54043-y.
Heating a ferromagnetic material is often perceived as detrimental for most applications. This is indeed the case for modern nano-scaled spintronic devices which are operated solely (at least ideally) by an electric current. Heat is a by-product of the current-driven operation and it deteriorates many functionalities of the device. A large scientific and technological effort is devoted these days to avoid heat in modern magnetic nano devices. Here we show that heat can be used to provide an additional and useful degree of freedom in the control of the local magnetization at the nanoscale. In a ferromagnetic nanowire, temperature is used to induce a magnetic switching through a perfectly deterministic mechanism. The nucleation of the magnetic domain walls that triggers the switching can be achieved at a field considerably smaller than the nucleation field and, importantly, the exact moment of the magnetic switching can be pre-determined with nanosecond precision by controlling the power delivered locally to the switching area. With the help of micromagnetic simulations and a theoretical model, we provide an accurate explanation of how this deterministic thermo-magnetic switching operates. The concepts described in this work may lead to an increased functionality in magnetic nano-devices based on magnetic domain walls.
对于大多数应用而言，加热铁磁材料通常被视为有害的。对于仅由电流（至少理想情况下）驱动运行的现代纳米级自旋电子器件来说，确实如此。热量是电流驱动运行的副产品，它会降低器件的许多功能。如今，大量的科学技术努力都致力于在现代磁性纳米器件中避免产生热量。在此我们表明，热量可用于在纳米尺度上控制局部磁化强度时提供额外且有用的自由度。在铁磁纳米线中，温度被用于通过一种完全确定性的机制诱导磁开关。触发开关的磁畴壁的成核可以在远小于成核场的磁场下实现，并且重要的是，通过控制局部输送到开关区域的功率，可以以纳秒精度预先确定磁开关的确切时刻。借助微磁模拟和理论模型，我们对这种确定性热磁开关的工作原理给出了准确解释。这项工作中描述的概念可能会增加基于磁畴壁的磁性纳米器件的功能。
