Superconducting properties of EuBa2Cu3O7 thin films on thick Sm2O3 buffer layers

Abstract There has been a tendency for micro-cracks to be generated in superconducting films deposited on R-Al 2 O 3 substrates with buffer layers. Thickening the buffer layer is one method for suppressing the generation of micro-cracks. When Sm 2 O 3 buffer layers were thickened, surface roughness ( R z ) of Sm 2 O 3 and EuBa 2 Cu 3 O 7 (EBCO) films increased and the critical current density ( J c ) deteriorated with increase in Sm 2 O 3 buffer layer thickness ( t Sm ). Then, the improvement of Sm 2 O 3 buffer layers on surface morphology and increment of J c of EBCO thin films deposited on the thick Sm 2 O 3 buffer layers were carried out. The surface roughness ( R z ) of Sm 2 O 3 buffer layers became small by optimizing sputtering conditions. R z of EBCO thin films decreased depending on that of Sm 2 O 3 buffer layers. The critical temperature ( T ce ) was 90 K and J c showed a high value of 1.6 MA/cm 2 at 77.3 K when t Sm was 2000 A.