Cryoelectric memories

The phenomenon of superconductivity is particularly attractive for computer memories because of the potential low cost per bit stored for memories larger than several million bits. Approximate expressions for the drive requirements of cryoelectric continuous film memories are developed based on Ginzburg-Landau theory. It is shown that crossed-film cryotrons can be matched to continuous film memories. Expressions for the sense output voltages for both line sense and cavity sense are given and compared with experiment. Sense voltages of one millivolt are obtainable from properly designed memories. Fabrication problems reduce the available geometrical tolerance in a memory array to an estimated ten per cent. The future of cryoelectric memories rests entirely on fabrication techniques, particularly in the ability to control impurities and grain parameters in the memory film.