Rare-earth dependence of photoinduced chain-oxygen ordering in RBa2Cu3O7-x (x approximate to 0.3) investigated by Raman scattering

BAHRS, S.; GONI, A.R.; THOMSEN, C.; MAIOROV, B.; NIEVA, G.; FAINSTEIN, A.

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

American Physical Society

Año: 2001 vol. 65 p. 245221 - 245225

0163-1829

We investigated a set of oxygen ? deficient RBa2Cu3O7-x (xapproximate to0.3) ceramic samples with Raman spectroscopy under resonant conditions for the defect-induced Cu-O chain related modes at 230 and 600 cm(-1). Emphasis was laid on the frequency and intensity of the modes for different rare-earth atoms, and especially on their dependence under illumination. The modes display photoinduced bleaching for all R, including the nonsuperconducting R = Pr. The dynamics of their bleaching following a temperature quench indicates similar complex relaxation processes for all samples. A simple stretched exponential with a common beta = 0.36+/-0.04 and a distribution of time constants ranging from 50 to 1400 s describes our data well. We discuss our results in connection to photoinduced chain-oxygen ordering in oxygen-deficient superconductors.