Correlation between Anisotropy Direction and Pulse Shape for Metal Evaporated Tape

Measured replay pukes, recorded on Metal Evaporated tape, show a strong asymmetry and dependence on the direction of tape movement. It is found that pulse height and pulse width are unequal for both directions of tape movement. This is attributed to the non longitudinal easy-axis direction which causes differences in headtape geometry for both directions resulting in a different transition width. A simulation model is proposed. The differences in pulse asymmetry and pulse width between both directions of tape movement are very well reproduced by this model. From X-ray diffraction measurements and the results of the simulations it is concluded that not the columns but the crystallites act as magnetic entities for this kind of tape. INTRODUCTION Metal Evaporated (ME) tape is being investigated as a new medium for high density magnetic tape recording. Production of this tape, according to the Continuously Varying Incidence (CVI) method. yields a magnetic layer with an easy axis parallel to the incidence plane and tilted about 15-30 degrees out of the plane of the film. It is known that the recording properties of M E tape depend on the direction of tape movement relative to the recording head 1.2.1. Figure 1 shows the geometry of tape and recording head and the definition of A and B direction of tape movement.