高B_S-CoNiFe電析膜の軟磁気特性に及ぼす成膜条件の影響  [in Japanese] Effect of Operating Concitions on the Soft Magnetic Properties of Electrodeposited  [in Japanese]

Electrodeposited CoNiFe soft magnetic films with high B_s were investigated for use as head core materials. It was found that a film consisting of an fcc phase structure with low Fe content has low magnetostriction of +2〜+6×10^<-6>. When the film composition was fixed at Co_<62>Ni_<12>Fe_<26>, the operating conditions for obtaining soft magnetic properties were optimized. It was found that soft magnetic thin films composed of fine crystals 10-15nm in diameter were obtained in condisitons of low pH(<3.0) and low current density (<40 mAcm^<-2>). In these operating conditions, a current efficiency of less than 80% with hydrogen evolution during the CoNiFe deposition was confirmed to be one of key factors for obtaining soft magnetic CoNiFe films with a suitably high B_s value. A typical Co_<62>Ni_<12>Fe_<26> film had the following properties. B_s=2.0T, H_c=1.7Oe, and λ_s=+4.9×10^<-6>.