Eur. Phys. J. B 22, 277-281 (2001)
https://doi.org/10.1007/PL00011148

Optical study of RE_1+xBa_2-xCu₃O₆ (RE = Nd, Sm) and YB_a2Cu₃O₆ in the mid infrared range

¹ Centre de recherche sur les propriétés électroniques des matériaux avancés, Département de physique, Université de Sherbrooke, Sherbrooke, Canada J1K 2R1
² Max Planck Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
³ Instituto de Pesquisa e Desenvolvimento, IP& D Univap - São Jose dos Campos, SP Av. Shishima Hifumi, 2911 12.244-000 Brazil
⁴ Institut für Festkörperphysik, 4 Forschungszentrum Karlsruhe, 76021 Karlsruhe, Germany

Corresponding author: ^a dbarba@physique.usherb.ca

Received: 14 February 2001
Revised: 12 April 2001
Published online: 15 August 2001

Abstract

Infrared reflectance, and transmission measurements as well as Raman scattering have been used to study the RE_1+xBa_2-xCu₃O₆ (RE = Nd, Sm) and YBa₂Cu₃O₆ absorption bands in the 1100-1500 cm^-1 infrared range as a function of temperature and beam polarization. In addition to two-phonon absorption between 1100 and 1170 cm^-1, we observe excitations around 1400 cm^-1, occurring in oxygen rich enclosures within the samples, and assign them to an excitation involving two-phonons plus the 270 cm^-1 local mode related to Cu-O broken chains. Thus, the previously reported possible magnetic origin of the 1436 cm^-1 sharp absorption band in YBa₂Cu₃O₆ is contested.