Print-through, erasability, playback losses: Different phenomena from the same roots

When testing some audio and video tapes made with different pigments, a strict correlation between print-through (in audio), variation of audio erasibility (in video tapes) and playback losses can be found. Our investigation on these phenomena lead us to correlate these properties with the defect structure of the oxides and with the amount and penetration of cobalt into the core of the particles. SIMS data on cobalt penetration, temperature dependence of coercivity/saturation and squareness confirmed the assumption that these performance parameters are strictly correlated to each other and such correlation is dependent on the mobility of Co
²⁺
and electron hopping of the Fe
²⁺
/Fe
³⁺
which is easier in particles bearing defects and large (cobalt-containing)/(cobalt-free) volume ratios.