DEPENDENCE OF THE ENERGY-GAP ON T(C) - ABSENCE OF SCALING IN THE COPPER-OXIDE SUPERCONDUCTORS

High-resolution electron energy loss spectroscopy has been used to investigate the energy gap (2DELTA) in a series of oxygen-doped Bi2Sr2CaCu2O8+delta single crystals with critical temperatures ranging from 71 to 94 K. Temperature dependent energy loss spectra demonstrate that 2DELTA develops sharply for T < T(c) in all of the samples, and that the magnitude of 2DELTA exceeds significantly 3.5kT(c). Furthermore, 2DELTA decreases only slightly as T(c) is reduced from 94 to 71 K, and thus, 2DELTA/kT(c) increases systematically as T(c) decreases. These results indicate that T(c) may be reduced significantly by strong inelastic scattering in the current copper oxides.