Abstract

Temperature-dependent frequency shift and linewidth data of the Raman active 337-nm⁻¹ CuO₂ in-plane bond-bending mode have been measured for five different oxygen stochiometries between x = 7.00 and x = 6.14 in polycrystalline samples. Softening and line broadening effects observed for the x = 7.00 sample are sharply reduced for x = 6.87 even though the superconducting transition temperature is similar. With a further reduction of oxygen content below x = 6.68, both the soft mode behavior and the line broadening effects completely disappear. These unexpected results could suggest a large variation in the interaction between the electronic system and the lattice as the oxygen content is varied.

© 1988 Optical Society of America