Bi-2223/Bi-2234 superlattice: its structural analysis and superconducting transition temperature

ABSTRACT (2223)2/(2234)2 superlattices have been synthesized by three target sequential sputter deposition of BiO, SrCu05O15 and CaCuO2 layers. The superstructure formed was analyzed in atomic layer scale by using some X-ray diffraction technique,such as interference of X-ray specular reflection, observation of the Laue's function pattern and a quantitative analysis of intergrowth. The superlattice, thus confirmed in the atomic layer scale, has a superconducting transition temperature (Ta) as high as the average of monophasic 2223 and 2234 films. The resistivity showed a similar angular dependence on themagnetic field orientation even at the temperature higher than the T of 2234. These results will be discussed by the holediffusion and/or the proximity effect between the 2223 and 2234 layers. 1. INTRODUCTIONHigh T superconducting Bi-Sr-Ca-Cu-O system is well known to have a series layered structure which can be expressedas 22(n-l)n in a general form, where n expresses the number of Cu02 planes in the unit sequence of stacking'. Superstructure