Soft Magnetic Properties of Laminated (Fe_(97)Al_3)_(1-x)-N_x/Ni_(81)Fe_(19) Films for Advanced Thin Film Heads

摘要

Laminated (Fe_(97)Al_3)_(1-x)-N_x/Ni_(81)Fe_(19) films have been prepared by reactive RF-diode (RFD) and DC-magnetron (DCM) sputtering within asputter machine developed for the production ofmagnetoresistive films. The thickness of the films was typically at≈0.5 #mu#m with a lamination period between 100A and 1200Aand a thickness ratio t_(FeAlN)/t_(NiFe) from 1 to 23. RFDsputtered films exhibit a high B_s (up to 20kG) and excellent softmagnetic behaviour (H_c=0.4Oe, H_k=3Oe, λ_s<1*10~(-6)) aslong as the lamination period is below a few hundred A. Thethickness uniformity of the films is better than +-3%. Uniform Ndistribution was proven by RBS investigation. XRDmeasurements reveal a nanocrystalline structure of both sublayersfor RFD and DCM sputtered films for a nitrogenconcentration>8at%, without exhibiting significant differencesbetween center and edge of the substrates. For films with DCMsputtered FeAlN sublayer, however, it was difficult to align theuniaxial magnetic anisotropy by the applied collinear magneticfield, particularly on larger substrates and at low nitrogen concentrations.