Thickness-Driven Control of Room Temperature Ferrimagnetic Skyrmions and their Topological Hall signature in GdFe Single Layers
Indian Institute of Technology Hyderabad（印度理工学院海德拉巴分校）；National Institute for Materials Science（国立材料研究所）；Tata Institute of Fundamental Research（塔塔基础研究所）
Saroj Kumar Mishra, Y. K. Takahashi, C. Malavika, Karthik V. Raman, Jyoti Ranjan Mohanty
Magnetic skyrmions are nanoscale, topologically protected spin textures with exceptional potential for high density data storage and energy efficient computing. Among various skyrmion hosting systems, rare earth transition metal ferrimagnets offer a promising platform due to their tunable magnetic properties and intrinsically low net magnetization. Despite this, the fundamental control of ferrimagnetic skyrmions in single layer films remains unexplored. Here, we demonstrate a viable route for engineering room temperature skyrmions in GdFe single layers through precise control of film thickness (60 to 80 nm). Thickness variation enables the systematic tuning of key magnetic parameters, including perpendicular magnetic anisotropy and saturation magnetization, thereby allowing precise control over skyrmion size and density. Magnetic force microscopy (MFM) reveals a clear thickness dependent evolution of isolated skyrmion characteristics, where skyrmion size decreases while skyrmion density increases with increasing GdFe film thickness, in agreement with micromagnetic simulations. At the same time, magnetotransport measurements show a systematic enhancement in the topological Hall resistivity with thickness, further corroborating the increased skyrmion density observed in MFM. Scanning transmission electron microscopy reveals a compositional gradient across the film thickness, indicative of structural asymmetry and potential inversion symmetry breaking, contributing to the emergence of a bulk Dzyaloshinskii Moriya interaction. Notably, sub 60nm skyrmions with high areal density are stabilized at room temperature. This work provides a viable route to tailor the properties of ferrimagnetic skyrmions in single-layer GdFe films, paving the way for the development of high-density ferrimagnetic skyrmionic devices.
Current-driven dynamics and ratchet effect of skyrmion bubbles in a ferrimagnetic insulator
磁skyrmions是一种紧凑的手性自旋织构，具有丰富的拓扑现象，并具有开发高密度存储器件和由自旋电流驱动的新型计算方案的潜力。在这里，我们展示了室温下的界面稳定性和电流驱动的控制skyrmion气泡的亚铁磁绝缘体Tm 3Fe 5 O 12（TmIG）耦合到Pt。我们跟踪电流引起的运动的个别skyrmion气泡。晶体的亚铁磁有序性以及自旋-轨道矩和钉扎的相互作用决定了TmIG中的skyrmion动力学，并导致以负偏转角和跳跃运动为特征的强skyrmion霍尔效应。此外，我们表明，速度和脱钉阈值的skyrmion气泡可以修改交换耦合TmIG的面内磁化Y3 Fe 5 O 12层，扭曲的自旋纹理的skyrmion，并导致其动态方向相关的整流。这种效应相当于一个磁性棘轮，被用来控制一个类似跑道的装置中的skyrmion流。
Electrically Sign-Reversible Topological Hall Effect in a Top-Gated Topological Insulator (Bi,Sb)2Te3 on a Ferrimagnetic Insulator Europium Iron Garnet
Topological Hall Effect in Antiferromagnetic Co doped Fe$_3$GaTe$_2$
National High Magnetic Field Laboratory（国家高磁场实验室）；Florida State University（佛罗里达州立大学）；Pohang University of Science and Technology（韩国科学技术院）；Baylor University（贝勒大学）
Revealing domain wall stability during ultrafast demagnetization
Max Planck Institute for Multidisciplinary Sciences（马克斯·普朗克多学科研究所）；Institute of Physics, University of Augsburg（奥格斯堡大学物理研究所）；School of Electrical Engineering, Tel Aviv University（特拉维夫大学电气工程学院）；th Physical Institute, University of Göttingen（哥廷根大学第四物理研究所）；Radboud University, Institute for Molecules and Materials（拉德堡德大学分子与材料研究所）
