  We extract the vortex lattice parameters using low-frequency two-coil mutual
inductance measurements in a 20-nm-thick superconducting a-MoGe thin film. We
fit the temperature dependence of ac penetration depth in the mixed state using
a model developed by Coffey and Clem and demonstrate a procedure for extracting
vortex lattice parameters such as pinning constant, vortex lattice drag
coefficient, and pinning potential barrier. We show that the extracted
parameters follow the magnetic field variation expected for a weakly pinned
2-dimensional vortex lattice.
