Thickness-dependent magnetic anisotropy in obliquely deposited Fe(001)/Pd thin film bilayers probed by VNA-FMR
Qeemat Gul1,2, Wei He(何为)1, Yan Li(李岩)1,2, Rui Sun(孙瑞)1,2, Na Li(李娜)1,2, Xu Yang(杨旭)1,2, Yang Li(李阳)1,2, Zi-Zhao Gong(弓子召)1,2, Zong-Kai Xie(谢宗凯)1,2, Xiang-Qun Zhang(张向群)1, Zhao-Hua Cheng(成昭华)1,2,3
1 State Key Laboratory of Magnetism and Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
2 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
3 Songshan Lake Materials Laboratory, Dongguan 523808, China
The thickness-dependent magnetic anisotropy of obliquely deposited Fe(001)/Pd thin films on Mg(001) is investigated by fitting the field-dependent resonant field curve using the Kittel equation. In this study, three Fe film samples with thicknesses of 50 monolayers (ML), 45 ML, and 32 ML deposited at 0°, 45°, and 55°, respectively, are used. The magnetic anisotropy constant obtained from ferromagnetic resonance (FMR) spectra exhibits a dominant fourfold magnetocrystalline anisotropy (MCA) at the normal deposition angle with larger Fe thickness. However, the in-plane uniaxial magnetic anisotropy (UMA) is induced by a higher oblique deposition angle and a smaller thickness. Its hard axis lies between the[100] and[010] directions. The FMR data-fitting analysis yields a precise measurement of smaller contributions to the magnetic anisotropy, such as in-plane UMA. Due to MCA, when the magnetic field is weaker than the saturated field, the magnetization direction does not always align with the external field. The squared frequency-dependent resonant field measurement gives an isotropic Landé g-factor of 2.07. Our results are consistent with previous experiments conducted on the magneto-optical Kerr effect (MOKE) and anisotropic magnetoresistance (AMR) systems. Thus, a vector network analyzer ferromagnetic resonance (VNA-FMR) test-method for finding UMA in obliquely deposited Fe(001)/Pd bilayer ferromagnetic thin films, and determining the magnetic anisotropy constants with respect to the film normal deposition, is proposed.
(Domain structure (including magnetic bubbles and vortices))
Fund:
Project supported by the National Basic Research Program of China (Grant Nos. 2015CB921403 and 2016YFA0300701), the National Natural Science Foundation of China (Grant Nos. 51427801, 11374350, and 51671212), and the Chinese Government Scholarship (Grant No. 2015GXYG37).
The 50 nm-thick yttrium iron garnet films with perpendicular magnetic anisotropy Shuyao Chen(陈姝瑶), Yunfei Xie(谢云飞), Yucong Yang(杨玉聪), Dong Gao(高栋), Donghua Liu(刘冬华), Lin Qin(秦林), Wei Yan(严巍), Bi Tan(谭碧), Qiuli Chen(陈秋丽), Tao Gong(龚涛), En Li(李恩), Lei Bi(毕磊), Tao Liu(刘涛), and Longjiang Deng(邓龙江). Chin. Phys. B, 2022, 31(4): 048503.
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