The effect of thermal agitations on the switching field distribution (SFD) of CoPtCr-Si O2 perpendicular media was investigated. Dc demagnetizing (DCD) magnetization curves and minor dc demagnetizing (M-DCD) magnetization curves were measured at applied field sweep rates of ∼10 and ∼ 108 Oes. We estimated the SFD from the difference between the DCD and M-DCD curves, and defined them as Δ Hr Hr (at ∼10 Oes) and Δ HrP HrP (at ∼ 108 Oes). The values of Δ HrP HrP were found to be 60%-70% of Δ Hr Hr. The difference between Δ HrP HrP and Δ Hr Hr should be caused by thermal agitation of the magnetization. The influence of the distribution of the thermal agitation on SFD was calculated using the distribution of the grain volumes. It is concluded that the SFD measured at vibrating-sample magnetometer (VSM) time scales is significantly influenced by thermal agitation of the magnetization, and reduction of the grain size distribution is the most effective way to reduce the SFD at VSM time scales.
ASJC Scopus subject areas
- Physics and Astronomy(all)