Large amplitudes and (critical) slowing-down of the order parameter fluctuations near the second-order tetragonal-to-orthorhombic phase transformation in YBa2Cu3Ox
Institut für Festkörperphysik, Technische Hochschule Darmstadt,
Hochschulstraße 6, D-64289 Darmstadt, Germany
Accepted: 23 June 1997
exhibits a second-order tetragonal-to-orthorhombic transformation, at least in wide temperature ranges. The order parameter is proportional to the orthorhombic strain or to the O population difference between and sites in the Cu(1) plane. Quasi-static anelasticity experiments were performed at 100 and on samples with O concentrations x between 6.29 and 6.9. The experiments show a drastic increase of both relaxation strength and relaxation time near the tetragonal-to-orthorhombic transformation at , thus demonstrating i) large amplitudes and ii) a (critical) slowing-down of the order parameter fluctuations.
PACS: 62.40.+i – Anelasticity, internal friction, stress relaxation, and mechanical resonances / 64.70.Kb – Solid-solid transitions / 66.30.-h – Diffusion in solids
© EDP Sciences, 1997