Dynamic scaling of magnetic flux noise near the Kosterlitz-Thouless-Berezinskii transition in overdamped Josephson junction arrays

We have used a dc superconducting quantum interference device to measure the magnetic flux noise generated by the equilibrium vortex density fluctuations associated with the Kosterlitz-Thouless-Berezinskii (KTB) transition in an overdamped Josephson junction array. At temperatures slightly above the KTB transition temperature, the noise is white for f < f(xi) and scales as 1/f for f > f(xi). Here f(xi) alpha xi(-z), where xi is the correlation length and z is the dynamic exponent. Moreover, when all frequencies are scaled by f(xi), data for different temperatures and frequencies collapse onto a single curve.