Internal friction of superconductor Rba2Cu3Oy(R = Y, Er, Ho and Dy)
Inagaki Masahiko; Teshima Yutaka; Ozawa Masakuni; Suzuki Suguru
Abstract:The internal friction (IF) of superconductor Rba2Cu3Oy(R = Y, Er, Ho and Dy) was measured by a torsional vibration method in the frequency range of 0.032 - 10 Hz. IF peaks were observed in the temperature range 410 - 520 K. The peak temperatures were influenced by the kind of rare earth ions in R site as well as the measured frequencies. The relaxation process was characterized by an average activation enthalpy of H = 1.17+-0.05 eV and a pre exponential factor of log(t0) = -13.0+-0.5 for Yba2Cu3Oy, H = 1.17+-0.05 eV and log(t0) = -13.0+-0.6 for ErBa2Cu3Oy, H = 1.24+-0.01 eV and log(t0) = -14.2+-0.1 for HoBa2Cu3O sub y, H = 1.7 +- 0.03 eV and log ((t0) = -1.5 +- 0. For DyBa2Cu3Oy, respectively. The relaxation time (t) decreased with increasing the ionic radius of rare earth ion in Re site. The activation enthalpy, however, was little affected by the ionic radius of R site cation in Rba2Cu3Oy. Key Words:oxide superconductor, internal friction, anelastic relaxation, rare earth