Circuit and module design for conductor-groove bubble memories

Copeland, J.A.; Josenhans, J.G.; Spiwak, R.

doi:10.1109/tmag.1973.1067598

Cited by 9 publications

(1 citation statement)

References 6 publications

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“…Parallel stretching is known from the conductorgroove system at 100 kHz [7). The stretch velocity can be as high as the saturation velocity even when the frequencyimposed average propagation velocity is lower.…”

Section: Stretching Problems and Resultsmentioning

confidence: 99%

Improved propagation, stretching and annihilation of magnetic bubbles in current-access devices

Dekker

Wiegman

Mierloo

et al. 1979

Journal of Applied Physics

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New functional elements have been tested for 16 μm-period current-access circuits in single and double mask structures. Improved propagate patterns exhibit 15% operating margins at 1 MHz frequency and 20 mA current. Heat dissipation drops to 0.3 mW per conductor period. In conventional CaGe-garnet films it has been possible to increase the maximum frequency to 1.9 MHz at 60 mA. In the first orthorhombic films to be processed, 4 MHz has been reached already at 20 mA current. High-frequency current-access stretching of bubbles prior to detection is discussed. Operating margins of 10% are obtained up to 700 kHz in a pattern that stretches bubbles normal to their propagation direction. High-frequency writing is obtained by combining a number of field-access generators with an annihilator in the conductor track. A compact current-field-access swap gate allows the closest possible packing of the field-access minor loops. These elements have not yet been combined for the same conductor structure. In principle, however, the functions required for a field and current-access major-minor loop chip are now available.

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Section: Stretching Problems and Resultsmentioning

confidence: 99%

Improved propagation, stretching and annihilation of magnetic bubbles in current-access devices

Dekker

Wiegman

Mierloo

et al. 1979

Journal of Applied Physics

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Current-Access Magnetic Bubble Circuits

Bobeck¹,

Blank²,

Butherus³

et al. 1979

Bell System Technical Journal

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Experimental and theoretical results from our work on current‐access technology show promise for high‐density, ∼107 bits/cm2, and high‐frequency, f > 1 MHz, bubble devices. We have operated current‐access devices where the bubble‐driving fields derive from two patterned conducting sheets instead of orthogonal field coils. Margins for generation, propagation, and transfer were studied on 8‐μm periods at 1 MHz. These 8‐μm period structures typically required 1.5 mA/μm per conducting sheet and dissipated 14 μW/bit. Single conducting‐sheet, current‐access circuitry also propagates bubbles but offers less design flexibility. We present design criteria, magnetic field equations, and design curves. Implementation of these devices required new magnetic materials with quality factor Q comparable to available garnets, yet higher mobility and lower dynamic coercivity. Of the three systems, (YLuSmCa)3(FeGe)5O12, (LaLuSmCa)3(FeGe)5O12, and (LaLuSm)3(FeGa)5O12, the last appears best suited; some room temperature characteristics of the composition La0.6Lu2.1Sm0.3Ga0.9Fe4.1O12 are 4πMs = 470G, μ = 750 cmS−1‐Oe−1, d = 1.6 μm, and ΔHc = 2 Oe across a bubble for the threshold of motion. Necessary improvements in processing were made with a radio‐frequency, chlorine‐containing plasma etch which produced metal patterns identical to those of the etch mask. We anticipate that current‐access devices, when compared to conventional field‐access devices, will achieve higher data rates, lower power consumption per bit, and greater storage densities with existing processing technologies.

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