Mfg. cobalt@-chrome recording tape - includes pretreating by ion or plasma etching in appropriate atmos.

摘要

The method of magnetic tape mfr. uses a polymer substrate on which a thin film of coherent ferromagnetic cobalt/chrome alloy is deposited by physical vapour deposition (PVD) where the mean magnetic moment and vertical coercive field strength is enhanced by pre-treatment of the substrate by a plasma, either ion etching (10-2000 eV) or plasma etching, e.g. 13.56 MH2, 100-1000 W in a suitable atmosphere. For example, either 10 minutes ion etching in N2 at 60 eV curve (b) characteristic. Example 2) 2 minutes ion etching in O2 curve (c). Without pre-treatment curve (a). USE/ADVANTAGE - Pre-treatment as described allows deposition at low temperatures: -20 to +100 deg.C such that coherent alloy crystals are formed without separation experienced at higher temperatures. Graph shows results. Tape is esp. suitable for vertical recording at high bit recording density.