Physical Principles of Magnetic Bubble Domain Memory Devices

Magnetic bubbles are cylindrical magnetic domains that may occur in a thin plate of a magnetic material in which the preferred ( easy ) direction of magnetization is perpendicular to the plane of the plate (Fig. 1). The magnetic bubble is separated from its environment by the cylindrical magnetic domain wall. The magnetization in the domain wall rotates through 180 degrees. In a bubble domain memory the presence of a magnetic bubble at a particular place and at a particular point of time represents a digital ‘one’, and its absence represents a ‘zero’.