BUBBLE MEMORY

A bubble memory device comprises a magnetic field shielding casing (12); a drive coil (14) for generating a rotating magnetic field within the casing; a bubble memory chip (18); and a magnet (16) for generating a bias magnetic field for the bubble memory chip, the magnet consists of a single permanent magnet of low permeability material having a first surface in thermal contact with a complementary surface of the bubble memory chip and within the drive coil, the magnet having a contoured second surface disposed opposite the first surface so that a central region of the magnet is thicker than an edge region whereby an enhanced magnetic field is created locally and the magnetic field is essentially uniform over the entire bubble memory chip.