| Popis: |
It has been established previously that thermal switching in high density magnetic media causes a significant time dependence of the coercivity at least for times >10/sup -8/ s. Here, the classical Arrhenius-Neel model assuming coherent rotation is applied to systems with distributions in volume, anisotropy and orientation and the numerical results for the time dependent remanent coercivity H/sub CR/(t), the viscosity S/sub R/, and the irreversible susceptibility, /spl chi//sub IRR/ compared to new experimental data on CrO/sub 2/ particulate tapes with varying orientation. The results for an anisotropy distribution are significantly different from a volume distribution and are in better agreement with the data. All distributions produce Sharrock type behavior for H/sub CR/(t), regardless of the distribution width. The model predicts that increasing the orientation distribution width will have very little effect on the fractional time dependence of H/sub CR/, in agreement with experiment which showed that S/sub R//spl chi/IRR/ and H/sub CR/(t) were essentially independent of orientation. Finally, the direct connection between S/sub R//spl chi/IRR/ and H/sub CR/(t) is confirmed theoretically and experimentally. |
