Modification system for particular function in bubble memory - uses laser beam continuously sweeping or providing localised pulse to reheat position on garnet film

摘要

A film of epitaxial ferrimagnetic garnet on a non-magnetic substrate is processed by implanting ions to form a memory. This process disturbs the crystal structure and is corrected by reheating the garnet film by a laser. The laser beam can continually sweep the surface of the film to cover particular areas. To reheat at a localised spot the laser beam is pulsed. The reheating action corrects the magnetic saturation properties of the film and requires reheating periods which depend on the increase in the collapsing field. This varies as a function of thickness of the epitaxial layer. The polarisation field applied to the material is 135 Oersteds.