Abstract Dynamic Young's modulus measurements, have been performed by the vibrating reed technique (102–104 Hz) on polycrystalline YBa2Cu3O7−x samples in the temperature range 300–900 K. A strong modulus softening, indicative of a phase transition, is measured at about x = 0.45. DTG measurements versus temperatures show in correspondence a maximum in the oxygen desorption rate. Long time modulus isotherms display an exponential trend linked to a thermally activated structural process with activation energy H = 0.9 ± 0.1 eV. On the basis of the experimental results a model for the structural transformation linked to the twinned interfaces mobility and to oxygen diffusion is presented and discussed.
Bonetti, E., Campari, E., Manfredini, T., Mantovani, S. (1991). Orthorhombic to tetragonal phase transition in YBa2Cu3O7−x observed by dynamic Young's modulus measurements. PHYSICA. C, SUPERCONDUCTIVITY, 179(4-6), 381-386 [10.1016/0921-4534(91)92186-F].
Orthorhombic to tetragonal phase transition in YBa2Cu3O7−x observed by dynamic Young's modulus measurements
Campari, E. G.Secondo
Investigation
;
1991
Abstract
Abstract Dynamic Young's modulus measurements, have been performed by the vibrating reed technique (102–104 Hz) on polycrystalline YBa2Cu3O7−x samples in the temperature range 300–900 K. A strong modulus softening, indicative of a phase transition, is measured at about x = 0.45. DTG measurements versus temperatures show in correspondence a maximum in the oxygen desorption rate. Long time modulus isotherms display an exponential trend linked to a thermally activated structural process with activation energy H = 0.9 ± 0.1 eV. On the basis of the experimental results a model for the structural transformation linked to the twinned interfaces mobility and to oxygen diffusion is presented and discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
