Fabrication of the Transport Study on YBa2Cu3O7-delta/ PrBa2(Cu(1-x)M(x))3O7 Type Multilayers

摘要

Ceramic samples of PrBa2(Cu(1-x)M(x))3O7 (PBCMO) were fabricated by substituting M = Al, Co, Fe, Ga, Ni, and Zn partially for Cu with substituting level x = 0.00, 0.05, 0.10, 0.15, and 0.20. X-ray diffraction shows that the lattice parameter of all PBCMO samples are very close to that of YBa2Cu3O7-(sub delta) (YBCO) while transport measurement indicated that the resistivities of all doped samples are order of magnitude higher than PrBa2Cu3O7 (PBCO). PBCMOs, therefore, are better insulator for YBCO then PBCO. prBa2(Cu0.8Al0.2)3O7 (PBCAO) and PrBa2(Cu0.8Ga0.2)3O7 (PBCG) were used as buffer layers for YBCO multilayers. Transport studies show that for a given thickness of YBCO layer the superconducting transition temperatures T(sub c) for all multilayers are the same in spite of the thickness of the buffer layers. This indicated that the buffer layers made of the PBCAO and PBCGO can effectively insulates the YBCO in the multilayers even when the thickness of the buffer layer is only 12.5 A. Increasing YBCO increases T(sub c). However, T(sub c) reaches a maximum when the YBCO thickness reaches 100 A indicating the superconducting length is (caret) 100 A. These materials could be ideal buffer layer for SIS Josephson junctions/devices.