MICROSTRUCTURE AND CRITICAL CURRENT DENSITY
of YBa₂Cu₃O_7-x + BaSnO₃ THICK FILMS GROWN
WITH PRE-MIXED PULSED LASER ABLATION TARGET

J. Burke^1,3, C.V. Varanasi^1,3, L. Brunke^1,3,
H. Wang², J.H. Lee², P.N. Barnes³

¹ University of Dayton Research Institute Dayton, Dayton, OH, 45469-0170, USA
² Texas A&M, College Station, TX, 77843-3128, USA
³ Air Force Research Laboratory , Wright-Patterson AFB, OH, 45433, USA

ABSTRACT - YBa₂Cu₃O_7-x + BaSnO₃ (BSO) thin films with BSO nanocolumns have been shown to have improved critical current density (JC) in applied magnetic fields.  Previously, a sectored target was used to grow thick (> 2.5 mm) YBCO + BSO films.  In the present study, a premixed YBCO + BSO (20 mol %) target was used to grow thick films (> 3 mm) to determine if similar high quality thick films can be obtained as with the sectored target approach. In the case of the premixed target, BSO material is continuously supplied as opposed to the sectored target method.  YBCO + BSO thick film samples processed using a premixed target were also found to have high JC at high fields with J_c > 10⁴ A/cm² at 8 T at 77 K, whereas typical YBCO films carry only 10² A/cm².  Transmission electron microscopy (TEM) on these films indicated that BSO nanocolumns with a diameter of ~8-11 nm extend through the thickness of the films.  The critical transition temperature (T_c) for the films was found to be ~87 K, regardless of thickness.

KEYWORDS:  high-temperature superconductors, BaSnO₃, critical current density, superconducting transition temperature, YBa₂Cu₃O_7-x.

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IEEE/CSC & ESAS EUROPEAN SUPERCONDUCTIVITY NEWS FORUM (ESNF), No. 10, October 2009
On June 29, 2009, this manuscript was submitted for possible publication in “Advances of Cryogenic Engineering (Materials)"