In-plane properties of (103)/(013) oriented YBCO films

The anisotropic in-plane electrical and superconducting behavior of (103)/( 013) oriented YBCO films has been investigated. The 150 nm thick samples we re fabricated on (110) SrTiO3 substrates by de sputtering from an inverted cylindrical magnetron, using a self-template growth process. The (103)/(013 ) lattice orientation was confirmed by the X-ray diffractometry measurement s and by polarised-light Raman spectroscopy. The film was patterned in 20 m u m width lines, in-plane oriented along different directions, in order to estimated the dependence of properties on the crystal orientation. Concerni ng the normal state electrical resistance, measured by a four contacts meth od at 100 K, a value rho(ab) = 0.64 m Omega cm and rho(c) = 3.50 m Omega cm is found for the bias current directed respectively along and across the c opper planes. The current voltage (I-V) characteristics were measured at di fferent temperatures. As expected the critical current density J(o) is larg er for the lines aligned with the copper planes, and decreases with decreas ing of the angle between current bias direction and the normal to the coppe r planes. The influence on vortex pinning of lattice twins occurring at the (103) and (013) grain boundaries is considered by analyzing the J(o) vs T dependence and the I-V characteristics compared with c-axis YBCO film stand ard features.