Micromagnetic understanding of the skyrmion Hall angle current dependence in perpendicularly magnetized ferromagnets

作     者：Riccardo Tomasello Anna Giordano Stefano Chiappini Roberto Zivieri Giulio Siracusano Vito Puliafito Israa Medlej Aurelio La Corte Bruno Azzerboni Mario Carpentieri Zhongming Zeng Giovanni Finocchio 

作者机构：Institute of Applied and Computational Mathematics FORTH GR-70013 Heraklion-Crete Greece Department of Mathematical and Computer Sciences Physical Sciences and Earth Sciences University of Messina I-98166 Messina Italy Istituto Nazionale di Geofisica e Vulcanologia Via di Vigna Murata 605 I-00143 Roma Italy Department of Electric Electronic and Computer Engineering University of Catania I-95125 Catania Italy Department of Engineering University of Messina I-98166 Messina Italy Department of Electrical and Information Engineering Politecnico di Bari I-70125 Bari Italy Key Laboratory of Nanodevices and Applications Suzhou Institute of Nano-tech and Nano-bionics Chinese Academy of Sciences Ruoshui Road 398 Suzhou 215123 People's Republic of China 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2018年第98卷第22期

页      面：224418-224418页

核心收录：

基　　金：executive programme of scientific and technological cooperation between Italy and China - Ministero degli Affari Esteri e della Cooperazione Internazionale [2016YFE0104100, CN16GR09] Hellenic Foundation for Research and Innovation General Secretariat for Research and Technology Gruppo Nazionale per la Fisica Matematica (GNFM) Istituto Nazionale di Alta Matematica (INdAM) "F. Severi" 

主　　题：Skyrmions Spintronics Multilayer thin films Micromagnetic modeling 

摘      要：The understanding of the dynamical properties of skyrmions is a fundamental aspect for the realization of a competitive skyrmion based technology beyond complementary metal-oxide semiconductors. Most of the theoretical approaches are based on the approximation of a rigid skyrmion. However, thermal fluctuations can drive a continuous change of the skyrmion size via the excitation of thermal modes. Here, by taking advantage of the Hilbert-Huang transform, we demonstrate that at least two thermal modes can be excited which are nonstationary in time. In addition, one limit of the rigid skyrmion approximation is that this hypothesis does not allow for correctly describing the recent experimental evidence of skyrmion Hall angle dependence on the amplitude of the driving force, which is proportional to the injected current. In this paper, we show that, in an ideal sample, the combined effect of fieldlike and dampinglike torques on a breathing skyrmion can indeed give rise to such a current dependent skyrmion Hall angle. While here we design and control the breathing mode of the skyrmion, our results can be linked to the experiments by considering that the thermal fluctuations and/or disorder can excite the breathing mode. We also develop a generalized Thiele equation and propose an experiment to validate our findings.