A one-dimensional chain state of vortex matter

Magnetic flux penetrates isotropic type II superconductors in flux-quantize d vortices, which arrange themselves into a lattice structure that is indep endent of the direction of the applied field(1). In extremely anisotropic h igh-transition-temperature (high-T-c) superconductors, a lattice of stacks of circular 'pancake' vortices forms when a magnetic field is applied perpe ndicular to the copper oxide layers, while an orthogonal elongated lattice of elliptical Josephson vortices forms when the applied field is parallel t o the layers(2-5). Here we report that when a tilted magnetic field is appl ied to single crystals of Bi2Sr2CaCu2O8+delta, these lattices can interact to form a new state of vortex matter in which all stacks of pancake vortice s intersect the Josephson vortices. The sublattice of Josephson vortices ca n therefore be used to manipulate the sublattice of pancake vortices. This result explains the suppression of irreversible magnetization by in-plane f ields as seen in Bi2Sr2CaCu2O8+delta crystals, a hitherto mysterious observ ation(6). The ability to manipulate sublattices could be important for flux -logic devices, where a 'bit' might be represented by a pancake vortex stac k, and the problem of vortex positioning is overcome through sublattice int eractions. This also enables the development of flux transducers and amplif iers, considerably broadening the scope for applications of anisotropic hig h-T-c superconductors.