Demagnetization-free longitudinal recording on flexible thin film metal media

The variation of demagnetization effects with media parameters for longitudinal contact recording has been investigated. Co-Re thin film metal media were sputtered onto flexible polyimide substrates. It was found that when the film thickness δ and demagnetizaton parameterB_{r}delta/H_{c}were less than 2 μ inch and 15 μinch, respectively, demagnetization-free longitudinal recording was obtained up to the recording density of 75 KFRPI at the head-to-medium spacing of 3 μ inch. As a result, recording densities of D50over 50 KFRPI were achieved with a 20 μinch gap head. For thicker films with larger demagnetization parameters, i.e.,delta geq 4 muinch andB_{r}delta/H_{c} geq 40 muinch, the longitudinal recording process approached the demagnetization limit. The results show that (with existing head field gradients) improvement in linear density of thin metal media can be obtained by an approximate factor of two before the demagnetization limit is reached.