Magnetic and electrical properties of NiFe-oxide mixture films

In order to improve the performance of magnetoresistive heads, higher saturation flux density Bs and higher resistivity ρ are preferable for Soft Adjacent Layer (SAL). NiFe-oxide (oxide=SiO₂ , Al₂O₃, ZrO₂ and Ta₂O ₅) mixture films were investigated for SAL. Among these films, the NiFe-ZrO₂ system is preferable because of its high Bs ρ and low coercivity. The stability of the NiFe-ZrO₂ system at 250°C was also investigated, which shows that Bs and ρ change by annealing and the changes increase with ZrO₂ content. MR devices of 3.2 μm width and 2.8 μm height were fabricated and transfer curves were measured. The maximum output voltage of the device in which NiFe-12mol% ZrO₂ was employed was 23% larger than the calculated value for the device in which NiFe-Nb (Bs ρ=60 Tesla μΩcm) was assumed to be employed