Tuesday, 08/19/08

Session Title:	Flux Pinning and Dynamics II - Engineered Pinning Arrangements
Session Chairs:	Paul Barnes, Air Force Research Laboratory, Wright-Patterson AFB & Takanobu Kiss, Kyushu University
Paper Number:	2MPD06
Start Time:	10:00am
Session Type:	Poster

Microstructural and Pinning Properties of YBa2Cu3O7-δ Thin Films Doped with Magnetic Nanoparticles J. Wang, Department of Physics, Texas A&M University; J. Yoon, H. Wang, Department of Electrical and Computer Engineering, Texas A&M University; D.G. Naugle, Department of Physics,Texas A&M University

In this research, we conducted a systematic study on the microstructural and physical properties of the YBa2Cu3O7-δ (YBCO) thin films doped with magnetic nanoparticles. We incorporated different magnetic nanoparticles (i.e., Ni, Fe2O3, etc.) with various particle doping concentrations (from 1 to 5 atom %). The dopants were incorporated either by laser ablation of a composite target through premixing the YBCO and dopant powders, or by alternative growth of the YBCO and dopant targets. Film thickness was controlled at 200nm range for all the samples. We conducted a detailed microstructural characterization on all the doped samples by X-ray diffraction (XRD), scanning electron microscopy (SEM), and cross-sectional transmission electron microscopy (TEM). The critical current densities at both self-field and in-field (Jcsf and Jcin-field (H//c)) and the critical transition temperature (Tc) of the doped YBCO thin films and a reference YBCO sample were measured by a Superconducting Quantum Interference Device (SQUID). The Tc of the doped YBCO films varies from 85K-89K and the Jc is in the range of 1.2-2MA/cm2 (at liquid N2, 75.5K) depending on the dopant and doping approach. The pinning properties of these doped YBCO films were explored at different temperatures and correlated with their microstructural characteristics.

This research was funded by the Air Force Office of Scientific Research (Contract No.: FA9550-0701-0108) and AFOSR summer faculty program, and AFRL – Propulsion Directorate. The SQUID magnetometer was purchased by funds provided by the National Science Foundation (NSF-9974899).