中国物理B ›› 2006, Vol. 15 ›› Issue (6): 1351-1355.doi: 10.1088/1009-1963/15/6/037

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Studies on high-moment soft magnetic FeCo/Co thin films

松本光功1, 刘小晰1, 森迫昭光1, 付煜2, 杨正2   

  1. (1)Department of Information Engineering, Shinshu University,Nagano 380-8553, Japan; (2)Institute of Magnetic Materials, Lanzhou University,Lanzhou, Louzhou 730000, China
  • 收稿日期:2005-10-26 修回日期:2006-03-07 出版日期:2006-06-20 发布日期:2006-06-20

Studies on high-moment soft magnetic FeCo/Co thin films

Fu Yu (付煜)a, Yang Zheng (杨正)a, Mitsunori Matsumoto (松本光功)b, Liu Xiao-Xi (刘小晰)b, Akimitsu Morisako (森迫昭光)b    

  1. a Institute of Magnetic Materials, Lanzhou University, Lanzhou, Louzhou 730000, China; b Department of Information Engineering, Shinshu University, Nagano 380-8553, Japan
  • Received:2005-10-26 Revised:2006-03-07 Online:2006-06-20 Published:2006-06-20

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摘要： The dependences of soft magnetic properties and microstructures of the sputtered FeCo (=Fe$_{65}$Co$_{35}$) films on Co underlayer thickness $t_{\rm Co}$, FeCo thickness $t_{\rm FeCo}$, substrate temperature $T_{\rm s}$ and target-substrate spacing $d_{\rm T-S}$ are studied. FeCo single layer generally shows a high coercivity with no obvious magnetic anisotropy. Excellent soft magnetic properties with saturation magnetization $\mu_{0}M_{\rm s}$ of 2.35 T and hard axis coercivity $H_{\rm ch}$ of 0.25 kA/m in FeCo films can be achieved by introducing a Co underlayer. It is shown that sandwiching a Co underlayer causes a change in orientation and reduction in grain size from 70 nm to about 10 nm in the FeCo layer. The magnetic softness can be explained by the Hoffmann's ripple theory due to the effect of grain size. The magnetic anisotropy can be controlled by changing $d_{\rm T-S}$, and a maximum of 14.3 kA/m for anisotropic field $H_{\rm k}$ is obtained with $d_{\rm T-S}$=18.0 cm.

关键词: FeCo film, sputtering conditions, high saturation magnetization, soft magnetic properties

Abstract: The dependences of soft magnetic properties and microstructures of the sputtered FeCo (=Fe$_{65}$Co$_{35}$) films on Co underlayer thickness $t_{\rm Co}$, FeCo thickness $t_{\rm FeCo}$, substrate temperature $T_{\rm s}$ and target-substrate spacing $d_{\rm T-S}$ are studied. FeCo single layer generally shows a high coercivity with no obvious magnetic anisotropy. Excellent soft magnetic properties with saturation magnetization $\mu_{0}M_{\rm s}$ of 2.35 T and hard axis coercivity $H_{\rm ch}$ of 0.25 kA/m in FeCo films can be achieved by introducing a Co underlayer. It is shown that sandwiching a Co underlayer causes a change in orientation and reduction in grain size from 70 nm to about 10 nm in the FeCo layer. The magnetic softness can be explained by the Hoffmann's ripple theory due to the effect of grain size. The magnetic anisotropy can be controlled by changing $d_{\rm T-S}$, and a maximum of 14.3 kA/m for anisotropic field $H_{\rm k}$ is obtained with $d_{\rm T-S}$=18.0 cm.

Key words: FeCo film, sputtering conditions, high saturation magnetization, soft magnetic properties

中图分类号:  (Magnetic properties of monolayers and thin films)

  • 75.70.Ak
61.05.cp (X-ray diffraction) 68.37.Lp (Transmission electron microscopy (TEM)) 68.55.-a (Thin film structure and morphology) 75.50.Bb (Fe and its alloys) 75.60.Ej (Magnetization curves, hysteresis, Barkhausen and related effects)