Fabrication of YGBCO/STO/YGBCO Trilayer Structure on IBAD-MgO Tape and In-Field Superconducting Property

Y
_0.5
Gd
_0.5
Ba
₂
Cu
₃
O
_7-δ
/SrTiO
₃
/Y
_0.5
Gd
_0.5
Ba
₂
Cu
₃
O
_7-δ
(YGBCO/STO/YGBCO) trilayer structure was grown on CeO
₂
buffered IBAD-MgO metal tapes under continuous moving deposition process. The YGBCO/STO/YGBCO trilayer as well as CeO
₂
buffer layer were deposited in a compact reel-to-reel pulsed laser deposition system. During the experiment, we only alter the thickness of STO interlayer from 10 to 80 nm. The thickness of YGBCO superconducting layers in different samples are of the same value 480 nm. Atomic force microscopy and scanning electron microscopy were used to observe the surface morphology. Four probe transport measurements and physical property measurement system were used to measure superconducting transition temperature T
_c0
and critical current density J
_c
of the samples at different temperature (77 and 4 K). The results showed that T
_c0
is nearly not affected by STO interlayer. However, superconducting transport properties and surface morphology were clearly affected by the thickness of STO interlayer. In the end of this paper, we present a reasonable explanation to these observed experimental results.