Observation of Skyrmions at Room-temperature in Amorphous Fe/Gd Films
Observation of Skyrmions at Room-temperature in Amorphous Fe/Gd Films
复制标题
室温下非晶 Fe/Gd 薄膜中斯格明子的观察
DOI：
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发表时间：
2015
影响因子：
2.8
通讯作者：
B. McMorran
中科院分区：
文献类型：
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作者：
J. Chess;S. Montoya;James Lee;Sujoy Roy;S. Kevan;E. Fullerton;B. McMorran
磁泡在20世纪70年代被研究为潜在的数据存储介质，由于其拓扑自旋结构[1]，近年来科学研究激增。一种特殊类型的具有旋转磁自旋的气泡（见图1）被称为skyrmion，是这些研究背后的主要推动力。Skyrmions的特征是具有非零手性或拓扑电荷，由Ns =∫m∙(∂xm ×∂ym)dxdy给出，其中m是归一化平面内磁化m = m (x, y)| m (x, y)| /。这些自旋织构最初是用中子散射在MnSi中观察到的[2-4]。围绕skyrmions的许多兴奋是由于它们在自旋电子学中的高应用潜力[5,6]。Yu等人使用LTEM在电流密度低至10 A·m的情况下观察到了FeGe中的skyrmion运动，比铁磁器件中移动畴壁所需的电流密度低10个数量级，这使得它们有望用于赛道存储器应用[5-7]。虽然以前的磁性斯基米子研究主要集中在非中心对称晶体上，其中Dzyaloshinskii-Moriya相互作用（DMI）稳定了斯基米子相，但在这里，我们提出了一种具有垂直磁各向异性的非晶铁磁材料的LTEM研究，该材料由Fe/Gd多层膜组成。
Magnetic bubbles, investigated in the 1970s as potential data storage media 1 , have seen a recent surge in scientific inquiry due to the their topological spin textures [1]. A specific type of bubble with whirling magnetic spins (see Fig. 1) called a skyrmion is the major driving force behind these investigations. Skyrmions are characterized by a non-zero chirality or topological charge, given by Ns = ∫ m ∙ (∂xm × ∂ym)dxdy, where m is the normalized in-plane magnetization m = M(x, y) |M(x, y)| ⁄ . These spin textures were first observed in MnSi using neutron scattering [2-4]. Much of the excitement surrounding skyrmions is due to their high potential for application in spintronics [5,6]. Yu et al. observed skyrmion motion in FeGe using LTEM at current densities as low as 10 A・m, ~10 orders of magnitude lower than that required to move domain walls in ferromagnetic devices making them promising for racetrack memory applications [5-7]. While previous magnetic skyrmion research has largely been focused on non-centrosymmetric crystals where the Dzyaloshinskii-Moriya interaction (DMI) stabilizes the skyrmion phase, here we present a LTEM study of an amorphous ferromagnetic material with perpendicular magnetic anisotropy, consisting of an Fe/Gd multilayer film.