JOSEPHSON VORTEX LATTICE TRANSFORMATIONS IN BSCCO-2212 SINGLE-CRYSTAL

Mixed state properties of highly anisotropic layered superconductor ar e studied with the out-of-plane resistance in high magnetic field, up to 15T, applied parallel to (ab)-plane of Bi2Sr2CaCu2Ox (BSCCO-2212) s ingle crystal with T-c > 90K. Sharp (Delta T less than or equal to 10 mK) hysteretic jumps in resistance temperature and field dependencies are discovered within the range of fields 5.5 less than or equal to H less than or equal to 11 T. Beyond that range of fields the jump-like features disappear while pronounced deviations from Arrenius law remai n till 15 T. Jump height and its hysteresis are nearly sweep rate inde pendent but could be eliminated by sufficiently high excitation curren t. The effect is found to be completely wiped out by a minor tilt of t he crystal from the parallel orientation H parallel to(ab), therefore it could be attributed to the Josephson vortex properties and possibly related with the first-order phase transition between the commensurab le Josephson vortex lattices predicted by Bulaevskii and Clem.