The magnetic transfer process

Abstract

The transfer of information from a magnetic surface master to a magnetic surface slave when they are brought in to intimate contact in the presence of an external magnetic field is discussed. The only effective component of the transfer field was found to be the component in the plane of transfer and collinear with the recorded magnetization. Steady fields were found to be only slightly inferior in transfer efficiency to alternating fields, and the optimum amplitude for both is equal to the remanence coercivity of the slave medium. The basic mechanism of the magnetic transfer process is shown to be the establishment of a relatively large susceptibility in the slave by the transfer field, thus rendering it a good receptor of the flux emanating from the magnetization gradients in the master. Under certain conditions it was found that digital information could be transferred from a high resolution master onto thick or low coercivity media with a significant improvement in resolution over what could be achieved by direct recording with conventional transducers on the same media.