Magnetic Writing with an Electron Beam

Experimental evidence is presented that magnetic writing with an electron beam is possible. The method is based on Curie-point writing which permits local reversal of the direction of magnetization in suitable, premagnetized magnetic films by temporarily elevating the temperature above the Curie point. By utilizing the dissipation energy of a focused electron beam for this purpose, quite well-defined traces of reversed magnetization could be recorded on MnBi films. The traces were erasable magnetically. Writing speeds corresponding to 3·104 bits/sec and information densities corresponding to 105 bits/cm2 could be achieved in these first experiments. Considerably higher writing speeds and some increase in information density should be feasible. By means of an electron mirror micrograph of the electronically recorded magnetic trace, evidence is presented which shows that, in addition to read-in with an electron beam, electronic read-out of the magnetically stored information is also possible. Electronic writing of magnetic half-tone images by controlling the size of the spots of reversed magnetization appears to be feasible also.