In Situ Growth of Epitaxial Superconducting Yba2Cu3O7-X Films on Insulating, Semiconducting and Ferroelectric K(Ta,Nb)O3 by Pulsed Laser Ablation

Abstract

AbstractK(Ta,Nb)O3 (KTN) is an interesting substrate for use in studies of epitaxial superconducting film‐substrate interactions because of a moderate lattice parameter mismatch with YBa2Cu3O7‐x and great versatility in electrical properties. KTN's properties are easily modified by doping to form an n‐type semiconductor and/or a ferroelectric with variable ferroelectric Tp. As an initial step in exploring such studies we have carried out what are believed to be the first epitaxial growth experiments of YBa2Cu3O7‐x films on insulating, semiconducting and ferroelectric KTN single crystals by pulsed laser ablation. We find that c‐axis‐normal epitaxial films can be consistently grown with TSc(R = 0) > 90K , △TSC ~1.5K, and Jc > IMA/cm2 on semiconducting and/or insulating KTaO3. However, growth on KNDO3 is problematic because of stresses generated by cooling the substrate through first order structural transitions, at even moderate cooling rates.