Soft Magnetic Properties of Sputtered FeZrBM (M=Co,Ni,Cr,V) Film

The soft magnetic properties of sputtered FeZrB films with Co, Ni, Cr or V added were investigated. While FeZrB ternary films did not exhibit soft magnetic properties in these experiments, addition of a few percent of a fourth element raises the permeability sufficiently for magnetic head applications. These changes correspond to the variations in the film magnetostriction. Any of the above additives changes the magnetostriction constant of FeZrB film from negative to positive. However, the effects of Co or Ni addition on crystallization are different from those of Cr or V. On adding Co or Ni, the crystallization temperature Tx is lowered, the lattice spacing Ls increases and the saturation magnetic flux density Bs rises, while addition of Cr or V makes Tx higher, Ls smaller and Bs lower. With respect to producing soft magnetic properties, Co is the best of the four added elements, and Fe87.6Co3.2Zr5.8B3.3 exhibits excellent soft magnetic properties after annealing at 550C (Bs approximately 18 kG, approximately 5000).