Arts Design & Architecture
Arts Design & Architecture
Publication Search Results
Results per page
Now showing 1 - 5 of 5
(1998) Wool, R; Kusefoglu, S; Khot, S; Zhao, R; Palmese, Gaetano; Boyd, Andrew; Fisher, Keith; Bandyopadhyay, Srikanta; Williams, J; Wang, ChaoyuanConference Paper
(1999) Zhao, Yong; Cheng, Chun-Chung; Zhang, HuaJournal ArticleThe influence of the flux flow on a.c. loss and magnetic penetration process in superconductors has been investigated. Asymptotic solutions of magnetic and electric fields and a.c. loss are presented in the form of a power series of [Lambda], the normalized frequency of the external a.c. magnetic field. The results show that the flux flow retards the response of inner magnetic field to the external one, which results in a deviation from the critical state model and a non-hysteretic loss. In the cases of H0>Hp, the deviation from the critical state is in the order of the second power of [Lambda]. The induced electric field and the macro-penetration depth are decreased by the slowdown of the flux movement, giving a negative contribution to the a.c. loss. However, the negative contribution is compensated by the increase of the current density, leading to a net increase of the a.c. loss. As a result, the a.c. loss exhibits a positive dependence on the frequency and the amplitude of the external magnetic field.
Correlation of low-temperature thermal expansion with oxygen nonstoichiometry in Bi17Pb03 Sr2Ca2Cu3O10+y(1999) Zhang, Hua; Zhao, Yong; Cheng, Chun-ChungJournal ArticleLow-temperature thermal expansion and its correlation with oxygen nonstoichiometry have been studied for Bi1.7Pb0.3Sr2Ca2Cu3O10+y samples. An anomalously big jump of the thermal expansion in the c direction of Bi1.7Pb0.3Sr2Ca2Cu3O10+y has been observed at a temperature slightly above the superconductivity transition temperature. The corresponding temperature and the magnitude of the jump are found to be correlated with the oxygen nonstoichiometry, carrier concentration and superconductivity. The results reveal that the anomalously big jump of the thermal expansion is an electron-assisted lattice softening transition. Its correlation with the superconductivity suggests that phonon-electron interaction still plays a certain role in the superconductivity in high-Tc cuprates.
(1998) Han, Shaowei; Zhao, Yong; Yang, C; Cheng, Chun-Chung; Zhang, Hua; Gu, Genda; Russell, Graeme; Koshizu, NJournal Article
(1998) Han, Shaowei; Zhao, Yong; Yang, C; Cheng, Chun-Chung; Zhang, Hua; Gu, Genda; Russell, Graeme; Koshizuka, NJournal ArticleThe 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.