Dependence of thermal activation energy on thickness and magnetic field in (Pr/sub 0.6/Y/sub 0.4/)Ba/sub 2/Cu/sub 3/O/sub 7//YBa/sub 2/Cu/sub 3/O/sub 7//(Pr/sub 0.6/Y/sub 0.4/)Ba /sub 2/Cu/sub 3/O/sub 7/ trilayers

Author

Kwon, C. ; Damaske, M. ; Qi Li ; Senapati, L. ; Warburton, P.A. ; Venkatesan, T.

Author_Institution

Dept. of Phys., Maryland Univ., College Park, MD, USA

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

1355

Lastpage

1358

Abstract

We have studied the activation energy of thermally activated vortex motion using (Pr/sub 0.6/Y/sub 0.4/)Ba/sub 2/Cu/sub 3/O/sub 7//YBa/sub 2/Cu/sub 3/O/sub 7//(Pr/sub 0.6/Y/sub 0.4/)Ba /sub 2/Cu/sub 3/O/sub 7/ trilayer structures. The dependence of the activation energy on the thickness of the YBa/sub 2/Cu/sub 3/O/sub 7/ layer and magnetic field was studied for YBa/sub 2/Cu/sub 3/O/sub 7/ layer thicknesses or 1.2/spl sim/120 nm and fields up to 7 T. We obtain a longitudinal vortex correlation length of 15/spl sim/20 mm in YBa/sub 2/Cu/sub 3/O/sub 7/. When the YBa/sub 2/Cu/sub 3/O/sub 7/ layer is a few unit-cells thick, the activation energy shows a logarithmic field dependence. In the thickness range between 10 to 30 nm, the dependence of the activation energy on magnetic field shows a crossover behavior from logarithmic dependence at low fields to one of power law, U/sub o//spl sim/H/sup -/spl alpha// (with /spl alpha//spl sim/0.5), at high fields. This crossover field does not depend on the thickness of the YBa/sub 2/Cu/sub 3/O/sub 7/ layer.<>

Keywords

barium compounds; critical currents; flux flow; high-temperature superconductors; praseodymium compounds; superconducting thin films; yttrium compounds; (Pr/sub 0.6/Y/sub 0.4/)Ba/sub 2/Cu/sub 3/O/sub 7/-YBa/sub 2/Cu/sub 3/O/sub 7/ -(Pr/sub 0.6/Y/sub 0.4/)Ba/sub 2/Cu/sub 3/O/sub 7/; (Pr/sub 0.6/Y/sub 0.4/)Ba/sub 2/Cu/sub 3/O/sub 7//YBa/sub 2/Cu/sub 3/O/sub 7//(Pr/sub 0.6/Y/sub 0.4/)Ba /sub 2/Cu/sub 3/O/sub 7/; 7 T; crossover field; high fields; high temperature superconductors; logarithmic field dependence; longitudinal vortex correlation length; low fields; magnetic field; power law; thermal activation energy; thermally activated vortex motion; trilayer thickness; Educational institutions; High temperature superconductors; Magnetic field measurement; Magnetic fields; Magnetic materials; Magnetic superlattices; Physics; Pulsed laser deposition; Superconductivity; Yttrium barium copper oxide;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.402815

Filename

402815