ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Thin film heads made of Co-based amorphous films with high saturation magnetization were reported to have superior capabilities for high-density magnetic recording.1 However, it was found that the uniaxial anisotropy is changed during head fabrication processes. In this study, we investigate the relaxation process of the uniaxial anisotropy of sputtered Co-Zr amorphous films. 1-μm-thick Co-Zr films of 1.4 T were prepared by rf sputtering. Uniaxial anisotropy was induced by the magnetic field of 50 Oe during deposition. After deposition, annealing was performed in the dc field of 500 Oe applied parallel to the easy axis of the films for stabilizing the uniaxial anisotropy (preannealing). The preannealing temperature was changed from 200 to 350 °C. The films were annealed again in a field along the hard axis to reduce the uniaxial anisotropy. Decrease of the anisotropy field was discussed based on Richter-type relaxation,2 where τ2 is the maximum and τ1 is the minimum relaxation time, respectively. Without preannealing, the bandwidth ln(τ2/τ1) is broad at higher annealing temperatures. With preannealing, the bandwidth becomes narrower and is almost constant for various preannealing temperatures. These results show that the relaxation processes with shorter relaxation times are all suppressed by preannealing. The average activation energy is 2.0 eV without preannealing. It increases with preannealing temperatures and reaches 2.9 eV at 350 °C. From these results, it is clear that preannealing at higher temperatures is more effective in stabilizing the uniaxial anisotropy in the CoZr amorphous films.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.344642
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