Edge profile studies of recorded flux transitions

A technique for visually observing simulated profiles of recorded digital flux transitions is used to verify the curved shape predicted by theoretical models and to analyze the effects of head-core material, gap length, recording current, coercive force, switching field distribution, and orientation of the easy-axis-of-magnetization. Flux transitions, contact-recorded on the edges of tape segments positioned with their planar surface perpendicular to the gap edges of the recording head, are visually observed and photographed with a magnetic viewer. Single current-pulses are used to record magnetization patterns on stationary tape segments to observe the cross section magnetized by the head field and illustrate penetration depth, transition width, and the location of recorded transitions relative to the gap edges. Square-wave signals are used to simulate the depth profile of digital flux transitions. Curved flux transitions with penetrations exceeding 2 mm and evidence of a "dead layer" erased by perpendicular head-field components, are observed using 75-125-μm gap iron-cobalt core heads and 1.5-A current on a magnetic tape with an Hcof 360 Oe. Penetration depths are empirically determined to depend on and on , where is the recording current. Vertical or perpendicular orientation is simulated using tape segments slit perpendicular to the easy-axis. The observed vertically recorded flux transitions have edge profiles at an angle of about 45°.