A study of vortex motion in YBa 2Cu 3O x thin films as revealed by the simultaneous appearance of longitudinal and transverse voltages

Abstract

We have carried out simultaneous measurement of longitudinal and transverse voltages which are generated when a YBa 2Cu 3O x thin film is subjected to magnetic field ( B) at an angle θ to current ( I), with both B and I parallel to the ab-plane. The measurements were made as a function of current and temperature both above and below the vortex glass transition temperatures. These studies have been helpful to differentiate between dissipation caused by vortex motion in the direction of the Lorentz force and that caused by other mechanisms. The results for the first time show that the dissipation caused by the Lorentz force has two components. Both the components show power law behavior. The first component is seen to increase sharply with the current and is attributed to vortex motion in the direction of the Lorentz force. The second component has been attributed to vortex motion induced thermodynamical fluctuations in the order parameter.