Sputter deposition of YBa2Cu3O7−x films using a hemispherical target in a Hg vapor triode plasma

Abstract
High‐quality stoichiometric films of YBa2 Cu3 O7−x have been grown epitaxially on SrTiO3 substrates by sputtering from a stoichiometric target of hemispherical shape using a Hg vapor triode plasma. Films exhibited superconducting transitions of a width ΔT∼2.5 K, with zero resistance being achieved at 89 K. From both the x rays and the temperature dependence of the normal‐state electrical resistance it can be inferred that the films contain an admixture of domains with either the c or a axes normal to the plane.