BI-EPITAXIAL GRAIN-BOUNDARIES IN YBA2CU3O7-X THIN-FILMS PREPARED BY PULSED-LASER DEPOSITION AND PULSED ORGANOMETALLIC BEAM EPITAXY - DIRECTCOMPARISON OF TRANSPORT-PROPERTIES AND GRAIN-BOUNDARY STRUCTURE

A set of 45 degrees [001] bi-epitaxial YB2Cu3O7-x thin film grain boun daries was studied to compare the effects of the microstructure on tra nsport properties. The grain boundaries were made using two different deposition techniques: pulsed laser deposition (PLD) and pulsed organo metallic beam epitaxy (POMBE). The transport properties were highly de pendent on the specific growth conditions used, resulting in both full y resistive and superconducting grain boundaries. Subsequent microstru ctural analysis of the measured boundaries showed that both types (sup erconducting and resistive) meandered on the length scale of hundreds of nanometers. The major structural difference between the boundaries was at the atomic scale where the resistive boundary had a 1 nm wide d isordered region. The direct correlation of microstructure to transpor t properties demonstrates the importance of the atomic scale structure in the resulting transport behavior.