Surface oxygen and electrical resistance of YBa2Cu4O8

Abstract The relationship between the intensity of the oxygen spectra from secondary ion mass spectroscopy (SIMS) and the electrical resistance in bulk was investigated for YBa 2 Cu 4 O 8 in comparison with Bi 2 Sr 2 CaCu 2 O 8 . In spite of the change in the intensity of the oxygen spectra, the electrical resistance in bulk was almost constant up to the annealing process at ∼ 300°C. The change in the work function of YBa 2 Cu 4 O 8 was also measured in order to characterize the surface electronic state. Superconductivity both at the surface and in bulk is discussed.