Stochastic domain wall depinning in permalloy nanowires with various types of notches
Y. Gao,
B. You,
H. L. Yang,
Q. F. Zhan,
Z. Li,
N. Lei,
W. S. Zhao,
J. Wu,
H. Q. Tu,
J. Wang,
L. J. Wei,
W. Zhang,
Y. B. Xu,
J. Du
Affiliations
Y. Gao
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People’s Republic of China
B. You
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People’s Republic of China
H. L. Yang
Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, People’s Republic of China
Q. F. Zhan
Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, People’s Republic of China
Z. Li
Fert Beijing Institute, Beihang University, Beijing, People’s Republic of China
N. Lei
Fert Beijing Institute, Beihang University, Beijing, People’s Republic of China
W. S. Zhao
Fert Beijing Institute, Beihang University, Beijing, People’s Republic of China
J. Wu
Department of Physics, University of York, York YO10 5DD, United Kingdom
H. Q. Tu
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People’s Republic of China
J. Wang
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People’s Republic of China
L. J. Wei
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People’s Republic of China
W. Zhang
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People’s Republic of China
Y. B. Xu
Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, People’s Republic of China
J. Du
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People’s Republic of China
Stochastic phenomena in magnetic nanowires based on domain wall (DW) motion is scientifically important thus to understand and control such behaviors are very meaningful. Here we report on the investigation of pinning and depinning of DWs in permalloy nanowires with six types of longitudinally asymmetric notches using focused magneto-optic Kerr effect (FMOKE) magnetometer and magnetic force microscopy (MFM). The hysteresis loops obtained by FMOKE indicate the generation of one or two distinct depinning fields by creating one notch close to the edge of the nanowires, in comparison multiple depinning processes occur in the nanowires with two identical notches symmetrically placed along the transverse direction, indicating more remarkable stochastic DW depinning phenomena. The MFM images verify the existence of DW in each type of nanowires and the DW sizes in the latter kind of nanowires are generally larger than those in the former ones. These observations can be explained by considering the thermal perturbation and edge or surface roughness effects in nanowires.
