Measurement of the switching speed limit in high coercivity magnetic media

A microstripline pulse field system that allows the switching speed of high coercivity magnetic media to be measured with pulse widths t>or=0.64 ns is discussed. The results for gamma Fe/sub 2/O/sub 3/ are in good agreement with the previous work of Thornley and Williams (1974). A DC bias field H/sub B/ was added to the pulse field to allow the high coercivity samples to be switched from saturation to zero remanence and the results analyzed in terms of the switching constant S/sub w/. At H/sub B/=400 Oe, S/sub w/(Co- gamma Fe/sub 2/O/sub 3/)=158 ns-Oe; at H/sub B/=700 Oe, S/sub W/ (barium ferrite)=135 ns-Oe; at H/sub B/=720 Oe, S/sub W/ (metal particle)=84 ns-Oe. The value of S/sub W/ increased with decreasing bias field, particularly for barium ferrite, indicating that in zero bias barium ferrite tapes it would be a factor of three slower than metal particle tapes.<
>