Chromium dioxide recording tape with an extremely narrow switching field distribution

An improved process has made possible the laboratory scale preparation of highly uniform particles of chromium dioxide. Video tapes have been coated with remanence curve switching field distribution (SFD) as low as 0.17, a value which has not been achieved with any other acicular material, and which approaches values reported for barium ferrite. Although the uniformity of the product is visible in the external particle geometry, this alone is not enough to explain the exceptionally narrow SFD, which is due to a more effective incorporation of iron dopant into the CrO₂