Sr2AlTaO6 films for multilayer high-temperature superconducting device applications

Abstract

Thin films of Sr2AlTaO6 (SAT) and multilayers of YBa2Cu3O7 (YBCO)/SAT have been grown by pulsed laser deposition on [001] LaAlO3 substrates. X-ray diffraction shows that SAT grows on [001] LaAlO3 with the c-axis oriented normal to the substrate plane. X-ray rocking curve and Rutherford backscattering channeling measurements on SAT films yield full width at half maximum of <0.3° and minimum backscattering yield χmin of 5%–7%, respectively, indicating good crystallinity. The real part of the dielectric constant εr is found to be ∼23–30, with ∼6×107 V/m static breakdown electric field. Both the dielectric constant and the static breakdown field show negligible temperature dependence between 10 and 300 K. A 100 nm×10 μm×50 μm YBCO film on SAT shows zero-field critical current density of ∼1.3×106 A/cm2 at 77 K, with a superconducting transition temperature Tc0 of ∼89.2 K.