Comment on "Observation of vortex-lattice melting in YBa2Cu3O7-delta by Seebeck-effect measurements"

The findings of Ghamlouch et al. [Phys. Rev. B 54, 9070 (1996)] on the jump in the thermoelectric power of high-T-c superconductors below the critical temperature in the presence of large magnetic fields are discussed. The co mplicated interplay between the vortex lattice thermodynamic transitions an d the transport property percolation transitions raises questions on their similarities, differences, and relationships with respect to the (B,T) phas e diagram features and the classical Kosterlitz-Thouless transition. A few comments pertain to the experimental details and others on the relevant rol e of thermomagnetic transport properties. [S0163-1829(99)04102-8].