The effect of dc bias fields on the switching speed in magnetic particulate media (abstract) : 38th Annual Conference on Magnetism and Magnetic Materials

1089-7550

AIP Digital Archive

Physics

New results on the switching speed limit in high coercivity particulate magnetic media have recently been reported using pulse fields with widths t〈1 ns. Because the pulse amplitude is presently limited to 〈950 Oe, switching measurements on media with higher coercivities were carried out in the presence of a dc bias field HB and the switching constant Sw at zero bias field estimated by extrapolating the data at several high bias fields to HB=0. The sensitivity of Sw to HB was significant particularly in barium ferrite so it is prudent to examine this dependency more carefully in a lower coercivity system in which Sw can be measured from 0≤HB≤HCR and HCR is the remanent coercivity. The results (Fig. 1) for a standard γ-Fe2O3 iron oxide tape with HCR=375 Oe show a nearly linear dependence of Sw on HB except for HB/HCR≥0.7 and validate our earlier speculation that switching in barium ferrite particles is significantly slower than in metal particles. The experimental results will be compared to the calculated switching time as a function of HB expected for an appropriate distribution of uniaxial, single domain particles.

Electronic Resource