In the study, the proposed method was used to analyse the electrical transport through ultra-thin SrTiO3 layers grown over YBa2Cu3O7 electrodes. This work contributes in a direct way to optimizing the growth of insulating barriers over high Tc superconductor electrodes, which helps to improve the performance of high critical temperature devices.

Using the approach, which was based on the theoretical Simmons model, the group found that the tunnelling of the carriers seems to be the main mechanism for the electrical transport in these systems. In general, a SrTiO3 barrier thickness of at least 1.6 nm (4 u.c.) is required to obtain a good insulation of the YBa2Cu3O7 electrode for small areas. The SrTiO3 layers present an energy barrier of 0.9 eV with an attenuation length of 0.23 nm, indicating their good insulating properties.

Controlled pulsed laser deposition allows high-quality ultra-thin STO layers to be grown over high Tc superconducting electrodes, with very good control of the barrier thickness for the fabrication of Josephson junctions.

Full details can be found in the journal Nanotechnology.