Operation of magnetic bubble domain dynamically-ordered dual-conductor shift registers

A variety of magnetic bubble-domain dual conductor-sheet shiftregisters was designed successfully which were capable of address reallocation based on the recency of address reference. The shiftregisters were fabricated on 5-μm bubble wafers of YEu-garnet, and device operation was demonstrated at drive frequencies ranging from 0.5Hz and 100kHz. Computer simulation showed that the minimum drive-current densities and bias margins of the well-designed shiftregisters for various functional modes were comparable to those for simple straight-line propagation at 100kHz drive when typical 5-μm bubble material was used. The operation of the shiftregisters observed on the fabricated chip and the results of computer simulation are described.