Josephson Coupling Between Superconducting Clusters In High-tc Materials

Diamagnetic moment for Bi2Sr2CaCu2O 8+δ (Bi:2212) and YBa2Cu3O 7-δ- (Y:123) crystals were measured at different fields H and temperatures. For the higher fields two distinct transition temperatures T g and TJ are identified, with Tg > T J. By increasing H the line Tg(H) shifts very slowly while TJ(H) shifts much faster to lower temperatures, displaying an upward curvature well described by a theory based on Josephson coupling between superconducting clusters. Here, we show data mainly for the Bi:2212 crystals, where sample dependent TJ(H) lines are clearly observed. © 2001 Elsevier Science B.V. All rights reserved.226-230PART I367369Seidler, G.T., (1991) Physica C, 183, p. 333Mackenzie, A.P., (1993) Phys. Rev. Lett., 71, p. 1238Osofsky, M.S., (1993) Phys. Rev. Lett., 71, p. 2315Alexandrov, A.S., (1996) Phys. Rev. Lett., 76, p. 983Gantmakher, V.F., (1999) JETP, 88, p. 148Joynt, R., (1990) Phys. Rev. B, 41, p. 4271Kotliar, G., Varma, C.M., (1996) Phys. Rev. Lett., 77, p. 2296Kim, W., (1998) Phys. Rev. B, 58, pp. R607Ullah, S., Dorsey, A.T., (1990) Phys. Rev. Lett., 65, p. 2066De Lima, O.F., unpublishedDe Lima, O.F., De Andrade Jr., R., (1995) Physica C, 248, p. 353Geshkenbein, V.B., (1998) Phys. Rev. Lett., 80, p. 5778Wen, H.H., (1999) Phys. Rev. Lett., 82, p. 410Nideröst, M., (1998) Phys. Rev. Lett., 81, p. 323