Anelastic relaxation of oxygen vacancies and high-T_csuperconductivity of YBa₂Cu₃O_7- 

Abstract

it is suggested that the variation of the internal friction (IF) characteristics of a single-phase YBCO specimen resulting from an increase of oxygen deficiency d is associated either with an ordeiing diffusioii process between iayers, or with an order/disorder diffusion process in the Cu (2) plane. The experimental results are explained in the light of these oxygen-vacancy migration processes. The essential connections between high-T, superconductivity, electric behaviour and oxygen-vacancy ordering are discussed.

Ferroelasticity in Y-Ba-Cu-O. II. Relaxational effects

“…Our work is motivated by a number of experimental investigations which have indicated the occurence of stress induced diffusive hopping of oxygen atoms in Y-Ba-Cu-0 (see, e.g., Sarikaya and Stren, 1988;Zhang et al, 1990). Anelastic relaxation measurements of flexural vibration modes (in the kHz range) also show very high diffusivity of oxygen: D = 6 x cm2/sec.…”