| 摘要 |
A magnetic recording medium comprises a layer of material including permanently aligned acicular magnetic particles having a first coercivity, and magnetic particles having a further coercivity higher than the first. The ratio of the volume per unit area of particles having said first coercivity to the volume per unit area of particles having said further coercivity is preferably between 3.4:6.6 and 5.5:4.5, and the particles having the further coercivity preferably comprise either barium ferrite or strontium ferrite platelets. The layer may be carried by a flexible substrate thereby forming a tape which can simultaneously record data permanently by means of the acicular particles and erasably by means of the particles having the further coercivity. The layer is manufactured using a slurry containing a mixture of the two types of particle, and a two stage alignment process. |
