High Magnetic Anisotropy Field in CoZr Thin Films

Magnetic properties and high frequency characteristics of Co(100-x)Zr(x)(x = 5-17) thin films have been investigated. The experimental results show that with the increase of Zr content, the saturation magnetization, 4 pi M(s), decreases from 12.3 kG for x = 5 to 7.3 kG for x = 17; induced anisotropic field, H(k), of the films increases from 232 Oe for x = 5 at first and reaches a maximum value of 266 Oe for x = 9; coercivive force along hard and easy direction, H(ch) and H(ce), ranges 1.6-7.1 Oe and 5.4-10.9 Oe, respectively. The highest ferromagnetic resonance frequency, f(FMR) of 4.9 GHz could be achieved for the films with x = 9. In addition, H(ch) and H(cc) are reduced by adopting Cu underlayer or Ni(20)Fe(80) underlayer to the studied CoZr films. The optimal magnetic properties of 4 pi M(s) = 12 kG, H(ce) = 5.4Oe, H(ch) = 0.7 Oe, H(k) = 258 Oe, rho = 233 mu Omega-cm and f(FMR) = 5 GHZ are obtained for Co(91)Zr(9) (110 nm)/Ni(20)Fe(80)(15 nm) bilayer.