Abstract
A novel magnetic read-out principle is proposed which can extract a high quality output from a high density recorded signal. The principle utilizes a sharp RF permeability change in a soft magnetic film due to a weak external field. This variation is caused by both magnetization rotation and ferromagnetic resonance.
A magnetic read-out head has been experimentally made which operates according to the novel principle. The manufactured head was evaluated by sinusoidal signals (0.5-10 MHz) which are saturatedly recorded in a magnetic tape with a ferrite ring head (head gap : 0.3 μm, track width : 100 μm).
The reproduced 0.5MHz signal level from the head is at least 35.7dB higher than that from the ring head, and the 5 MHz signal is 17.6-22.5 dB robustly detected by the novel head. The carrier-to-noise ratio for a 5 MHz carrier (1 μm wavelength) is 44-47 dB and is insusceptible to Ni-Fe film thickness.
