INFRARED-SPECTROSCOPY OF ND2-YCEYCUO4 (Y=0-0.2) SINGLE-CRYSTALS

The data on the room temperature IR reflectivity (50-9000 cm-1) of the Nd(2-y)Ce(y)CuO4 single crystals (y = [0-0.2]) are reported. The in-plane reflectivity spectra (E perpendicular c) were found to be extremely sensitive to the Ce content. In contrast to this, the out-of-plane reflectivity (E parallel-to c) was found to be independent from doping. The reflectivity anisotropy of the superconducting crystals is close to that of La- and Bi-based materials, thus indicating the quasi 2D electronic structure of the above compounds. We obtained evidence that transition temperature decreases for the values of Ce content being higher than y = 0.155 due to decrease of the electron-phonon coupling constant.