Fabrication of Thick $\hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{7-{\rm x}}$ Films on Optimized $\hbox{SrTiO}_{3}$ Buffered-MgO Single Crystals

In this work, we studied the optimum deposition conditions for SrTiO
₃
(STO) buffers deposited on MgO single crystals substrates by PLD method. We found that 120 nm thick STO films, deposited at 730
^o
C , present the smoothest surface and a minimum FWMH of the (002) reflection. High quality, smooth and free-crack (YBCO) thick superconducting films have then been fabricated using a deposition temperature of 800
^o
C on STO-buffered MgO substrates. A 373 nm thick YBCO/STO/Mg
₂
O film can carry current densities (77 K, 0 T) of 1.4 MA/ cm
²
and J
_c
(77 K, 5 T) of 1.4 MA/ cm
²
The J
_c
in high field overcomes the current transported in same experimental conditions by 180 nm thick YBCO film grown on Y
₂
O
₃
-decorated STO single crystal. For 1350 nm thick YBCO/STO/MgO film the J
_c
(77 K, 0 T) is about 0.8 MA/cm
²
and J
_c
(77 K, 5 T) is 0.09 MA/cm
²
.