Artigo
Oxygen mobility and structural phase transformation in Bi2Sr2CaCu2O8+delta measured by anelastic spectroscopy
Fecha
2004-08-01Registro en:
Physica C-superconductivity and Its Applications. Amsterdam: Elsevier B.V., v. 408, p. 743-744, 2004.
0921-4534
10.1016/j.physc.2004.03.074
WOS:000224051700316
2949983867418338
8506867595279427
0000-0002-3336-309X
Autor
Universidade Estadual Paulista (Unesp)
Universidade de São Paulo (USP)
Resumen
One of the most studied ceramic superconductors for application has been, undoubtedly, Bi2Sr2CaCu2O8+delta. Although being a multiphasic material, it has proved to have great advantages compared to other ceramic systems. Measurements of the elastic energy loss and modulus (anelastic spectroscopy) as a function of temperature call distinguish among different atomic jumps that occur inside the various phases or at different local ordering. In this paper, mechanical loss spectra of Bi2Sr2CaCu2O8+delta bar shaped samples, made by a conventional method, have been measured between 80 and 600 K, using a torsion pendulum operating in frequencies below 50 Hz, for samples annealed in vacuum up to 600 K. Possible relaxation mechanisms are proposed to explain the origin of the mechanical-loss peaks observed 300 and 500 K. (C) 2004 Elsevier B.V. All rights reserved.