Magnetic anisotropy of Permalloy (Py) antidot square lattice was investigated by torquemetry method using Rotation Magneto-Optic Kerr Effect (ROTMOKE). We find that there exists a field-dependent 4-fold magnetic anisotropy with the easy magnetization axis along the  axis of the antidot square lattice. In addition, there also exists an artifact of a uniaxial magnetic anisotropy in ROTMOKE result. We show that both results are due to the period wiggling of the magnetization in space which was confirmed by magnetic imaging using magnetic transmission soft x-ray microscopy (MTXM). Micromagnetic simulation from MuMax3 supports the wiggling structure of the magnetization, as well as reproduces ROTMOKE result. A simplified model was developed based on the periodic wiggling of the magnetization and successfully explored the physical origin of the field-dependent 4-fold anisotropy and the artifact of the uniaxial anisotropy.
Bibliographical noteKAUST Repository Item: Exported on 2021-11-11
Acknowledged KAUST grant number(s): OSR-2019-CRG8-4081
Acknowledgements: This work is supported primarily by US Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE-AC02-05CH11231 (van der Waals heterostructures program, KCWF16) which provided for T.Y.W. A.Z. and Z.Q.Q. Additional support was provided by Users with Excellence Program of Hefei Science Center CAS (No. 2021HSC-UE003) which provided for Q.L.; King Abdullah University of Science and Technology (KAUST), Office of Sponsored Research (OSR) and under the Award No. OSR-2019-CRG8-4081 which provided for X.Z.; Lawrence Berkeley National Laboratory through the Laboratory Directed Research and Development (LDRD) Program which provided for H.-S.H. and M.Y.I.; Future Materials Discovery Program through the National Research Foundation of Korea (No. 2015M3D1A1070467) and Science Research Center Program through the National Research Foundation of Korea (No. 2015R1A5A1009962) which provided for C.H. and Z.Q.Q. The operations of the Advanced Light Source at Lawrence Berkeley National Laboratory are supported by the Director, Office of Science, Office of Basic Energy Sciences, and U.S. Department of Energy under Contract No. DE-AC02–05CH11231; C.S. gratefully acknowledges support from a Kavli Energy NanoScience Institute/Heising–Simons Fellowship.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics