Studies for Loop-to-Loop Transfer Modes in Ion-implanted Bubble Devices

Abstract

Transfer modes from cache to storage loops in ion-implanted bubble devices with on-chip cache organization have been studied. The advance mode (MODE-A) in data transfer from cache to storage loops (c-s transfer), which is required by the data recurrence condition, was simulated using the gate pseudo-operation technique where current was not applied to the gate conductor. The difference in bubble behaviors in c-s transfer operation among three samples with different δλ values (≡λ₁₀₀-λ₁₁₁) can be explained qualitatively based on the lattice strain relaxation model. According to the model, a strong negative chargedwall due to the difference between magnetostriction constants, λ₁₀₀ and λ₁₁₁, rises at the pattern edge normal to the [121] direction, which is almost equal to the rotating drive field direction corresponding to the gate pulse end phase for MODE-A operation. A potential barrier formed by the negative charged-wall is found which prevents a bubble from moving in the right direction along the corner pattern edge. Therefore, in order for c-s transfer to operate stably in MODE-A, the difference between λ₁₀₀ and λ₁₁₁ must be sufficientlly diminished.