Abstract
We have measured ac magnetic susceptibility of the electron-doped superconducting with applied magnetic field either parallel or perpendicular to the plane (-plane or -axis). For -plane, a peak in the temperature dependence of the screening current is revealed as a dip in the real part of the ac susceptibility . The temperature at which this peak anomaly occurs decreases with increasing field and lies well below the irreversibility line in the phase diagram. This peak effect may arise from the phase transition of Josephson vortices from a quasiordered vortex lattice to a disordered glass phase.
- Received 5 July 2006
DOI:https://doi.org/10.1103/PhysRevB.75.134505
©2007 American Physical Society