When EuBa
2Cu
3O
7-δ (EuBCO) thin films of more than 3,000 Å in thickness were deposited on R-Al
2O
3 substrates with a CeO
2 buffer layer, there was a tendency for micro-cracks to be generated due to the difference in thermal expansion coefficient. If a thick CeO
2 buffer layer with a flat surface is used, it is believed that microcrack generation can be suppressed as the result of reducing the influence of thermal distortion. In this study, in order to improve the surface morphology of a thick CeO
2 buffer layer, we focused on the effect of sputtering gas pressure. Sputtering gas pressure was changed from 0.5 to 7 Pa when a CeO
2 buffer layer of 3,000 Å in thickness was prepared, and the effects of sputtering gas pressure on deposition rate (
Rd), surface morphology and crystallinity were examined. The effect of sputtering gas pressure on the superconducting characteristics of the EuBCO thin film grown on the CeO
2 buffer layer was also examined. Smooth CeO
2 buffer layers were obtained at 3 Pa, and the EuBCO thin films deposited on the CeO
2 buffer layer showed a critical temperature (
Tce) of 90 K and a critical current density (
Jc) values of about 4.0 MA/cm
2 at 77.3 K.
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