Optical Properties of Ba sub 2 YCu sub 3 O sub (7-delta)
21 March 1988
We have studied the reflectivity of twinned, c-axis oriented crystals in the a,b (CuO) plane as a function of T from room temperature to 4K and as a function of frequency from ~3meV to ~3eV. We find substantial differences among samples and some variation with T in both the normal and superconducting states.