Effect of Li Substitution on Bi (Pb)-2223 Superconductors
Saad F. Oboudi1, Muna M. Abbas2, Nadein Q. Raoof3
1Saad F. Oboudi, Department of Physics, College of Science, Baghdad University, Bagdad, Iran.
2Muna M. Abbas, Department of Physics, College of Science, Baghdad University, Bagdad, Iran.
3Nadein Q. Raoof, Department of Physics, College of Science, Baghdad University, Bagdad, Iran.
Manuscript received on May 26, 2014. | Revised Manuscript received on June 12, 2014. | Manuscript published on June 30, 2014. | PP: 94-97 | Volume-3, Issue-5, June 2014. | Retrieval Number: E3122063514/2013©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: Samples of stoichiometric composition Bi2-xLixPb0.3Sr2Ca2 Cu3O10+δ with x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 were prepared by a solid state reaction method. The process consists of three steps. Firstly a Bi2-xLixPb0.3Sr2Ca2 Cu3O10+δ sample was sintered in the air at 850 °C for 50 hrs; subsequently the sintered sample was regrind and sintered again at 850 °C for another 50 hrs. While in the third step the sample resintered it at 830 °C for 40 hrs, and then slowly cooled in furnace with a rate of 2 ºC/min. The process enhances growing a superconducting phase unidirectional and suppresses the high phase intrusion which leading to the production of well textured samples. Li particles were introduced into Bi2Pb0.3Sr2Ca2u3O10+δ powder in various concentrations. Bulk samples were made from the Bi2223/Li powder and heat-treated at various processes. The phase formation and the microstructure were studied for different amounts of Li. It was found that sample with x = 0.3 Li showed the highest Tc-zero at 130 K. Increasing Li content to 0.5 decreases the critical temperature to 113 K. The samples were characterized by X-ray diffraction, and DC electrical resistivity. The X-ray diffraction studies were done at room temperature and the lattice constants of the material were determined by indexing all the peaks observed.
Keywords: Bi-based superconductors, Li substitution, Phase formation.