• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effects Of Nb2o5 Addition On The Formation And Properties Of Bi-based Superconductors

Ghazanfari, Nader 01 August 2006 (has links) (PDF)
Effects of Nb2O5 addition on the formation and properties of the Bi-based superconductors were studied. The superconducting samples were synthesized by two different methods, the solid state reaction (SSR) and ammonium nitrate melt route (ANM) to obtain information about the growth techniques. Ten samples (five with each method) with the chemical compositions of Bi1.6Pb0.4Sr2Ca2Cu3NbxOy, with x= 0.00, 0.05, 0.10, 0.20, and 0.30 were prepared. Phase identification, structural and microstructural analysis were carried out using powder X-ray diffraction method, scanning electron microscopy and energy dispersive X-ray (EDX) analysis. The transition temperature and the critical current measurements were carried out using the electromagnetic measurement system. The critical parameters of the samples were also determined by AC susceptibility and magnetization measurements. Improvements in the formation of the Bi-2223 phase with Nb addition have been observed by both methods. The ANM method leads mixtures of Bi-2223 and Bi-2212 phases, but with the SSR method pure Bi-2223 phase was obtained. With small amounts of Nb addition the critical temperature, Tc, remains the same for ANM samples and it increases for the SSR samples. For both series of samples Tc decreases with further increase of Nb content. With Nb addition the critical currents of the ANM sample almost remain the same and those of the SSR samples increases. Observations based on AC susceptibility measurements showed that Nb addition improve inter-grain coupling. Inductive critical current densities obtained from magnetization measurements agree with the critical currents stated above and show that Jc increase with increase Nb content.

Page generated in 0.1105 seconds