Observation of the vortex-glass transition in YBa2Cu3O7 by phase-resolved current-voltage measurements

Autor(en)

W. Lang, C. Fussenegger, S. Proyer, E. Stangl, D. Bäuerle

Abstrakt

We report on investigations of the current-dependent ac impedance Z at 17 Hz of a YBa2Cu3O7 thin-film microbridge in magnetic fields from 1 to 8 T. A phase-sensitive lock-in technique was applied and supplemented by a pulsed method for high current densities. Above the vortex-glass transition temperature T-g a constant Z(j) is observed with low current densities j, and a power-law behavior at high currents. Below T-g, the curvature of the Re Z vs. J curve is negative in a log-log plot. The Re Z(j) isotherms can be collapsed onto two universal scaling functions according to the predictions of the vortex-glass model. Close to and below T-g, a phase lag between current and voltage appears, which saturates to finite values at low j and to zero at high j. The phase lag within the constant-Z(j) region remains below the critical value, predicted theoretically by Dorsey, if T > T-g and approaches 90 degrees at T <T-g indicating the freezing of the vortices into the dissipation-free vortex-glass state.

Organisation(en)

Elektronische Materialeigenschaften

Journal

Zeitschrift für Physik B - Condensed Matter

Band

100

Seiten

13-18

Anzahl der Seiten

6

ISSN

0722-3277

DOI

https://doi.org/10.1007/s002570050087

Publikationsdatum

1996

Peer-reviewed

Ja

ÖFOS 2012

103018 Materialphysik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/c3b18648-9c9c-4073-a38e-12d78c927702