Anisotropic electric field effect in YBa2Cu3O7−x thin films grown on (110) SrTiO3 substrates

Abstract The electric field effect on the resistance, the critical temperature and the critical current density of YBa 2 Cu 3 O 7− x thin films with (103)/(013) and (110) orientations grown on (110) SrTiO 3 substrates was investigated. To this end thin film heterostructures consisting of YBa 2 Cu 3 O 7− x /(110) SrTiO 3 /Au were prepared in situ by pulsed laser ablation. The superconducting film was patterned into two perpendicular channels being parallel to the [001] S and [110] S substrate directions, respectively. The (103)/(013) films enabled us to study the influence of specific 90° grain boundaries on the field effect which had to be crossed by the transport current flowing in [110] S direction. Because a current in [001] S direction flowed in c -axis direction of (110) films they were used to compare the field effect on nominal c -axis and a b -plane transport occurring in the perpendicular [110] S channel. It emerged that the field effect on the resistance and the critical current density was anisotropic in (103)/(013) films with significantly stronger effects across specific 90° grain boundaries. In the (110) films, however, only a slight difference of the field effect on c -axis and a b -plane transport could be observed.