中国物理B ›› 2009, Vol. 18 ›› Issue (5): 2063-2067.doi: 10.1088/1674-1056/18/5/056

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Microwave properties and surface topography of softmagnetic films with high resistivity

马强, 江建军, 别少伟, 田斌, 梁培, 何华辉   

  1. Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
  • 收稿日期:2008-10-11 修回日期:2008-10-31 出版日期:2009-05-20 发布日期:2009-05-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 50371029 and 50771047), the Program for the New Century Excellent Talents in University of the Ministry of Education, China (Grant No NCET20420702), and the Natural Science F

Microwave properties and surface topography of soft magnetic films with high resistivity

Ma Qiang(马强), Jiang Jian-Jun(江建军), Bie Shao-Wei(别少伟)†, Tian Bin(田斌), Liang Pei(梁培), and He Hua-Hui(何华辉)   

  1. Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2008-10-11 Revised:2008-10-31 Online:2009-05-20 Published:2009-05-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 50371029 and 50771047), the Program for the New Century Excellent Talents in University of the Ministry of Education, China (Grant No NCET20420702), and the Natural Science F

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摘要： A single layer of CoFeB and a multilayer of CoFeB--MgO films are prepared by means of DC/RF magnetron sputter deposition. The excellent microwave properties and high electrical resistivity are simultaneously achieved in the discontinuous multilayer structure of [Co44Fe44B12(0.7nm)/MgO(0.4nm)]_{40} film. This film has a high permeability ({μ \prime }) (larger than 100 below 2.1GHz), a high magnetic loss (μ'') (larger than 100 in a range from 1.5 to 3.3GHz), a resistivity of 3.3× 10*

关键词: soft magnetic films, microwave properties, resistivity, roughness

Abstract: A single layer of CoFeB and a multilayer of CoFeB--MgO films are prepared by means of DC/RF magnetron sputter deposition. The excellent microwave properties and high electrical resistivity are simultaneously achieved in the  discontinuous multilayer structure of [Co$_{44}$Fe$_{44}$B$_{12}$(0.7 nm)/MgO(0.4 nm)]$_{40}$ film. This film has a high permeability ($\mu \prime $) (larger than 100 below 2.1 GHz), a high magnetic loss ($\mu''$) (larger  than 100 in a range from 1.5 to 3.3 GHz), a resistivity of 3.3$\times 10^{3}\mu \Omega \cdot$ cm, a saturation magnetization of 1.2 T, and an in-plane uniaxial anisotropy field of 5.5 kA/m. The microstructure and the  surface topography of the film are also analysed. The relatively large surface roughness for the discontinuous film is responsible for the wide frequency band of magnetic loss. The magnetic loss and the high resistivity  indicate that the discontinuous CoFeB--MgO multilayer film has potential applications in microwave absorbers and electromagnetic interference (EMI) shielding materials in a GHz frequency range.

Key words: soft magnetic films, microwave properties, resistivity, roughness

中图分类号:  (Magnetic properties of interfaces (multilayers, superlattices, heterostructures))

  • 75.70.Cn
68.55.A- (Nucleation and growth) 68.35.B- (Structure of clean surfaces (and surface reconstruction)) 81.15.Cd (Deposition by sputtering) 75.60.Ej (Magnetization curves, hysteresis, Barkhausen and related effects) 75.30.Gw (Magnetic anisotropy)