Synthesis and characterization of Cu-doped SrTiO3 powders and sol-gel processed buffer layers on IBAD MgO templates

Copper-doped SrTiO₃ (STO) powders were processed by conventional bulk preparation techniques to establish solubility limits of Cu in STO. The maximum solubility of Cu in STO was identified to be ∼1%. Epitaxial Cu-doped SrTiO₃ (STO) buffer layers were then prepared by pulsed laser deposition (PLD) and chemical solution deposition (CSD) on ion-beam-assisted deposition (IBAD) magnesium oxide (MgO) flexible metallic textured tapes. Transmission electron microscopy (TEM) analysis of the ∼100 nm thick buffer layer deposited by PLD showed a smooth Cu-doped STO/MgO interface. Films deposited by CSD had an average film thickness of 30 nm and exhibited growth by heterogeneous nucleation with no secondary reaction phases. YBa₂Cu₃O_7-∂ (YBCO) films were deposited onto the Cu-doped STO buffer layers by PLD.