Wall state stability of bubbles in uniaxial double-layer LPE films

Wall state transitions and stability measurements were performed on a series of double-layer films which contain 2μm bubbles. The film comprises a capping layer with uniaxial anisotropy but low saturation magnetization and a bubble layer with high saturation magnetization. Both types of domain wall states, "0" and "1", are found to be stable over a wide range of in-plane field values and even down to zero field. A theoretical explanation of the domain wall transitions and structure is also given. For bubble lattice devices, the new composite films may remove the in-plane field constraints on device functions imposed by the bubble wall states.