Superconducting and Structural Properties of EuBa₂Cu₃O_7-δ Ultrathin Films Deposited on MgO(100) Substrates Using Magnetron Sputtering

Abstract

EuBa 2 Cu 3 O 7-δ thin films were produced on MgO(100) substrates at 580°C using planar-type magnetron sputtering and were studied by X-ray diffraction and RHEED. The c -oriented films were epitaxially grown with a crystal orientation of [110] EuBaCuO //[010] MgO . Films more than 1000 Å thick exhibited T c endpoints of ∼90 K. As film thickness decreased, superconducting properties deteriorated. However, even films with 2-unit-cell thickness became superconducting. The cause of the deterioration of superconducting properties in ultrathin films is discussed on the basis of the relationship between lattice matching and structural properties.