Abstract: This bubble domain sensor is capable of sensing the presence or absence of a bubble at a predetermined location within bubble supporting material regardless of whether the bubble is stationary or moving through that location. A magnetostrictive material layer, such as a thin film having an area approximately equal to the area of a bubble domain, is positioned with respect to the bubble material such that it is magnetically influenced by the closure field of a bubble at the predetermined location. A conductor, such as a strip conductor, is positioned in contact with the magnetostrictive material. A sonic device launches sonic wave pulses which pass in the vicinity of the magnetostrictive material layer. The sonic wave pulse stresses the magnetostrictive material, and when the magnetostrictive material is magnetically influenced by a bubble, the stress changes or rotates its magnetization thereby inducing an electric signal in the conductor.

Abstract: A multi-state memory cell which uses magnetic bubble domains in uniaxial material is described. The cell includes a channel in which a number of stable bubble positions separated by barriers is formed and on which select conductors are positioned to switch a bubble from one stable position to another on a threshold basis by means of coincident currents. A cell in accordance with this invention may take the form of a four-state-two conductor cell, two-bistable-state two-conductor cell, multi-state six conductor cell and six-state three-conductor cell and include destructive or non-destructive readout.

Abstract: The magnetic bubble propagate circuit combines the forces on a bubble due to the properties of a modulated channel in a bubble material with the forces on the bubble due to a field produced by discrete magnetic poles P.sub.1 and P.sub.2 to move the bubble along a predetermined path. The channels may be modulated in width or in depth and be of the mesa or groove type so as to have a channel with periodically spaced stable bubbles positions O which are separated by barrier positions X. The poles P.sub.1 and P.sub.2 consist of soft-magnetic material bars which are placed either along the channel perpendicular thereto such that alternate ends of sequential bars overlap the channel between pairs of stable positions, each bar providing a pole P.sub.1 or P.sub.2, or along the channel parallel thereto such that the ends of the bars fall between adjacent pairs of stable positions, each bar providing a pole P.sub.1 and P.sub.2. The propagate circuit thus has repeated pattern O, X, P.sub.1, O, X, P.sub.2. The bars P.