Operation of magnetic bubble logic devices

Dual-conductor current-access magnetic-bubble logic devices have been fabricated using 2-micron lithography on garnet with 2-micron-diameter bubbles. The devices include an AND/OR gate, a comparator gate, and a switch gate. The operating margins of these gates were measured at 100 kHz and at 1 MHz with a sampling optical microscope. A 30-Oe operating bias-field margin was obtained for all the logic gates. The experimental results are in good agreement with the computer simulation results. The simulated failure modes of operation are discussed.