Engineering

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Now showing 1 - 6 of 6
  • (1997) Han, Shaowei; Zhao, Yong; Zhang, Hua; Gu, Genda; Russell, Graeme; Koshizuka, N
    Journal Article
    A resistivity anomaly near the superconducting transition temperature is observed in the ab-plane of as-grown Bi2Sr2CaCu2O8 (Bi-2 2 1 2) single crystals. The resistivity at the peak is much larger than the normal state resistivity around 100 K. The peak vanished gradually with increasing the applied magnetic field. I---V curves of the Bi-2 2 1 2 samples also exhibit a peak close to the transition steps, vanishing gradually with increasing intrinsic granularity of high-Tc superconductors.

  • (1997) Zhao, Yong; Zhang, Hua; Gu, Genda; Han, Shaowei; Russell, Graeme; Koshizuka, N
    Journal Article
    Voltage noise of the Bi2Sr2CaCu2O3+x single crystal below Tc is by an asymptotic power spectrum method. The low-frequency noise, power, Sa(T), shows a peak at Y = Tp. This peak is found to be closely related to the vortex lattice melting temperature. Near the peak T = Tp the power spectrum, Sa(f), exhibits a power-law fall-off, while at much lower temperatures Sa(f) dramaticaily deviates from the power-law behaviour, showing some broad peaks which are superposed upon a background with an exponential-law characteristic. The estimated correlation dimension of the noise data reveals that the vortex motion is highly correlatas at the early stage of melting, then develops into an extended dissipative dynamic system with self-organized criticality, showing a 1/fa behaviour. The correlated motion disappears when the lattice completely melts.

  • (1997) Russell, Graeme; Gu, Genda; Han, Shaowei; Zhao, Yong; Zhang, Hua; Koshizuka, N
    Journal Article
    A resistivity anomaly near the superconducting transition temperature is observed in the ab-plane of as-grown Bi2Sr2CaCu2O8 (Bi-2 2 1 2) single crystals. The resistivity at the peak is much larger than the normal state resistivity around 100 K. The peak vanished gradually with increasing the applied magnetic field. I---V curves of the Bi-2 2 1 2 samples also exhibit a peak close to the transition steps, vanishing gradually with increasing intrinsic granularity of high-Tc superconductors.

  • (1998) Han, Shaowei; Zhao, Yong; Yang, C; Cheng, Chun-Chung; Zhang, Hua; Gu, Genda; Russell, Graeme; Koshizu, N
    Journal Article

  • (1997) Zhao, Yong; Zhang, Hua; Gu, Genda; Han, Shaowei; Russell, Graeme; Koshizuka, N
    Journal Article

  • (1998) Han, Shaowei; Zhao, Yong; Yang, C; Cheng, Chun-Chung; Zhang, Hua; Gu, Genda; Russell, Graeme; Koshizuka, N
    Journal Article
    The vortex-glass-liquid transition in Bi---Sr---Ca---Cu---O (BSCCO) intergrowth single crystals in which some CuO2 trilayers are inserted into the Bi2Sr2CaCu2O8 matrix has been studied. The curvature of the log V-logI curves for CuO2 trilayers is found to change from negative to positive with increasing magnetic field and a scaling behaviour for the vortex-glass state is observed. The magnetic field dependence of the vortex-glass transition temperature, TG, qualitatively obeys the relation H(TG) (Tc − Tg)2v0, with v0 = 1.15 ± 0.2, which is larger than the 2/3 predicted theoretically for an isotropic 3D system. Our results reveal that the vortex-glass transition exists in a system constructed with CuO2 trilayers.