Magnetic bubble memory device

DETAILED DESCRIPTION The present invention has been made to eliminate the conventional drawbacks and has for its object to provide a magnetic bubble memory device having minor loops of high density without impairing bias magnetic field margin.
In order to achieve the above object of the present invention, there is provided a magnetic bubble memory device comprising: a magnetic film for holding magnetic bubbles; a first insulating layer formed on the magentic film; a conductive layer selectively formed on the first insulating layer; a second insulating layer formed on the conductive layer and part of said the insulating layer, for surrounding the conductive layer; and a bubble propagation path layer which is patterned on the second insulating layer and the first insulating layer to provide propagation path patterns of different pattern periods; wherein the distance between said magnetic film and said bubble propagation path layer is made smaller at a propagation pattern of shorter period than at a propagation pattern of longer period.