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

BAHRS S, GONI AR, THOMSEN C, MAIOROV B, NIEVA G, FAINSTEIN A

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

Año: 2002 vol. 65 p. 24522 - 24522

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.