High coercivity chromium dioxide

Chromium dioxide in the 560–680 Oe coercivity range has been optimized for high density magnetic recording and is being produced at plant scale. The stabilized powders have residual magnetic moment of 33–35 emu/g, average crystal length of 0.6 μ, average aspect ratio of 20, and specific surface area of 20–40 m2/g. Magnetic tapes made with these oxides improve video output on state-of-the-art video cassette recorders by 2–4 dB and S/N by 1–3 dB, compared with current standard tapes, and also have very low audio noise. Magnetostrictive loss on replay is negligible, as on standard CrO2 tapes.