Stability of single skyrmionic bits.
Stability of single skyrmionic bits.
复制标题
DOI：
10.1038/ncomms9455
复制
发表时间：
2015-10-14
影响因子：
16.6
通讯作者：
Wiesendanger R
中科院分区：
文献类型：
--
作者：
Hagemeister J;Romming N;von Bergmann K;Vedmedenko EY;Wiesendanger R
在拓扑结构上不同的天子态和铁磁态之间的转换已经被提出作为信息存储的比特操作。虽然数据存储设备需要长寿命的比特，但到目前为止还没有解决Skyrmions的寿命问题。在这里，我们通过原子蒙特卡罗模拟表明，天子态和铁磁态的依赖于场的平均寿命相对于临界磁场具有高度的不对称性，在该临界磁场下，这些寿命是相同的。根据我们的计算，Skyrmions稳定性增强的主要原因是Skyrmions和铁磁激活能与场的关系不同，而且Skyrmions的尝试频率较低，而不是势垒的高度。我们利用这一知识提出了一种通过比较理论和实验数据来确定有效材料参数和量化蒙特卡罗时间标度的方法。磁天子是在外加磁场作用下在螺旋磁铁中拓扑稳定的旋转磁化织构。在这里，作者使用蒙特卡罗模拟来探索Skyrmions相对于铁磁相的稳定性以及它们作为单个比特的潜力。
The switching between topologically distinct skyrmionic and ferromagnetic states has been proposed as a bit operation for information storage. While long lifetimes of the bits are required for data storage devices, the lifetimes of skyrmions have not been addressed so far. Here we show by means of atomistic Monte Carlo simulations that the field-dependent mean lifetimes of the skyrmionic and ferromagnetic states have a high asymmetry with respect to the critical magnetic field, at which these lifetimes are identical. According to our calculations, the main reason for the enhanced stability of skyrmions is a different field dependence of skyrmionic and ferromagnetic activation energies and a lower attempt frequency of skyrmions rather than the height of energy barriers. We use this knowledge to propose a procedure for the determination of effective material parameters and the quantification of the Monte Carlo timescale from the comparison of theoretical and experimental data. Magnetic skyrmions are swirling magnetization textures which are topologically stabilized in helical magnets under an applied magnetic field. Here, the authors use Monte Carlo simulations to explore the stability of skyrmions against a ferromagnetic phase and their potential as single bits.