Optimization of REBa2Cu3O7−x on Flexible, Dielectric Substrates for High-Frequency Applications

We report the fabrication of superconducting REBa
₂
Cu
₃
O
_7−
x
(REBCO) {RE = (Gd,Y)} thin films using metal organic chemical vapor deposition (MOCVD) on flexible, yttria stabilized zirconia (YSZ) substrates. Low surface resistance (R
_s
) of ∼0.1 mΩ/square (@ 25 K, 9.4 GHz) and critical current density (
J_c
)
>
1 MA/cm
²
(@77K) have been achieved. Homogeneous REBCO growth was confirmed using scanning hall probe microscopy (SHPM) over sample length with uniformity in
J_c
∼ 10%. Key MOCVD process parameters such as heater susceptor temperature, precursor composition and residual oxygen concentration have been optimized. Crystallographic texture of the fabricated films was assessed by 2D X-ray Diffraction (2D-XRD). Composition of the REBCO films was determined using inductively coupled plasma mass spectrometry (ICP-MS) and optimum superconducting performance was observed near a composition of Ba/Cu = 0.72. High-quality REBCO films on flexible, dielectric substrates can be utilized as resonators, strip-lines, microwave circuits, band pass filters, next generation radiation detectors and superconducting quantum interference devices (SQUID).