Influence of annealing in hydrogen on magnetoresistive effect of sputtered NiCo films

Magnetoresistive effect of NiCo films prepared by r.f. diode sputtering was investigated for the application upon magnetic sensors and magnetic thin film heads (MR heads). The sputtered films without heat treatment may be characterized by small value (<=1.1%) of magnetoresistive effect due to its small value of Δrho and high electrical resistivity rho. It was found that annealing in hydrogen is substantially effective to reduce the oxide and to bring the grain growth in films, and it results in large value of magnetoresistive effect because of decreased value of rho and increased value of Δrho. The films of which Ni concentration is in range 60 to 80 weight percent showed 4.5 -- 5.3% of magnetoresistive effect as a result of annealing in hydrogen at 4000C for 60 min. (author)