Gilbert damping in CoFeB/GaAs(001) film with enhanced in-plane uniaxial magnetic anisotropy

H Q Tu; B Liu; D W Huang; X Z Ruan; B You; Z C Huang; Y Zhai; Y Gao; J Wang; L J Wei; Y Yuan; Y B Xu; J Du

doi:10.1038/srep43971

Gilbert damping in CoFeB/GaAs(001) film with enhanced in-plane uniaxial magnetic anisotropy

Sci Rep. 2017 Mar 6:7:43971. doi: 10.1038/srep43971.

Authors

H Q Tu^{1

2}, B Liu³, D W Huang³, X Z Ruan³, B You^{1

4}, Z C Huang⁵, Y Zhai⁵, Y Gao¹, J Wang¹, L J Wei¹, Y Yuan¹, Y B Xu³, J Du^{1

4}

Affiliations

¹ National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.
² Department of Mathematics and Physics, Nanjing Institute of Technology, Nanjing 211167, P. R. China.
³ School of Electronic Science and Engineering, Nanjing University, Nanjing 210046, P. R. China.
⁴ Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, P. R. China.
⁵ Department of Physics and Jiangsu Key Laboratory of Advanced Metallic Materials, Southeast University, Nanjing 211189, P. R. China.

Abstract

A 3.5 nm amorphous CoFeB film was sputtered on GaAs (001) wafer substrate without applying magnetic field during deposition, and a significant in-plane uniaxial magnetic anisotropy (UMA) field (H_u) of about 300 Oe could be achieved. To precisely determine the intrinsic Gilbert damping constant (α) of this film, both ferromagnetic resonance (FMR) and time-resolved magneto-optical Kerr effect (TRMOKE) techniques were utilized. With good fitting of the dynamic spectra of FMR and TRMOKE, α is calculated to be 0.010 and 0.013, respectively. Obviously, the latter is 30% larger than the former, which is due to the transient heating effect during the TRMOKE measurement. In comparison with ordinary amorphous CoFeB films with negligible magnetic anisotropies, α is enhanced significantly in the CoFeB/GaAs(001) film, which may be mainly resulted from the enhanced spin-orbit coupling induced by the CoFeB/GaAs interface. However, the significant in-plane UMA plays minor role in the enhancement of α.

Publication types

Research Support, Non-U.S. Gov't