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:	2MPD07
Start Time:	10:00am
Session Type:	Poster

Nanostructure and Resistive Flux Flow in PLD YBCO Films Containing Nanoparticles V.M. Pan, V.S. Flis, A.A. Kalenyuk, A.L. Kasatkin, V.O. Moskalyuk, A.I. Rebikov, V.A. Semenov, V.L. Svetchnikov, C.G. Tretiatchenko, Institute for Metal Physics, Kiev, Ukraine

The nanostructure of YBCO films with addition of up to 3 mass% of BaZrO_3 (BZO), pulsed laser deposited onto LaAlO_3 single crystal substrates at different temperatures, is examined by X-ray diffraction analysis, high resolution TEM and electron backscattering diffraction. The disk-shaped nanoparticles about 4 nm in diameter are observed. An ordering of BZO nanodots along the c-axis and a distribution in the ab-plane are compared with the results of computer simulation of the doped film growth. Experimental dependences of the number, size and distribution of nanoparticles on the BZO concentration and the deposition temperature suggest that the ordering occurs both by the buried island mechanism as well as due to threading edge dislocations, at which the nanodots are preferably formed. Moreover, the nanoparticles prevent polygonization during high temperature deposition. Low frequency AC susceptibility measurements reveal that BZO nanodots result in an enhancement of the critical current. I-V curves show that the flux motion regime in the resistive state also changes.