Anisotropic in-plane properties of (103)/(013) oriented YBa2Cu3O7-delta thin films grown on exact and miscut (110) SrTiO3 substrates

YBa2Cu3O7-delta (YBCO) grows upon (110) oriented SrTiO3 substrates with two equivalent tilt orientations and exhibits regions of each 45 degrees tilt. If the substrate orientation is "miscut'' from the exact (110) orientation , the two:tilts are no longer energetically equivalent, enabling the fabric ation of films with controllable tilt disorder. We have carried out a compa rative study of(103)/(013) YBCO films deposited onto exact cut (0 degrees) substrates, and onto 3 degrees and 5 degrees miscut substrates where the pr oportion of minority tilt is about 5% and 2%, respectively. The two-tempera ture sputter growth process that has been developed yields films which are essentially free of the (110) orientation and which have normal-state resis tivities rho(001) comparable to rho(a) for a high-quality single crystal. I n the superconducting state the three classes of film each exhibit features characteristic of a phase transition for both the [001] and the orthogonal transport current directions. Data from the 0 degrees and 5 degrees films: exhibit excellent scaling collapse over very wide ranges of temperature; d ata from the 3 degrees films scale somewhat less well. Surprisingly, the tr ansition temperatures differ significantly between the two transport direct ions in the 0 degrees films at all magnetic fields investigated and in the 3 degrees films at higher fields. The nonuniversality of the scaling parame ters, the very high values of the exponent z, and the dependence of the tra nsition temperature on transport direction cast doubt on a conventional int erpretation in terms of a vortex-glass melting transition. Studies of the O hmic behavior of the 5 degrees films show an in-plane anisotropy which rema ins constant as the system passes from the normal state, through the superc onducting flux flow regime to the Ohmic thermally activated Aux creep regio n. This constancy is consistent with the anisotropy in the vortex damping b eing equal to the normal-state anisotropy.