Mechanism of flux-line lattice melting of high-Tcsuperconductors

We investigate a mechanism of generation of dislocations for the melting of flux lattices in high-${\mathit{T}}_{\mathit{c}}$ oxide superconductors. The free energy is the difference of the elastic energy and that from the interaction of the dislocation with the flux-lattice vibrations. For Bi-Sr-Ca-Cu-O and Y-Ba-Cu-O with the flux interaction potential derived by Sudbo/ and Brandt, the free energy of an edge dislocation becomes zero at temperatures that are within 20% of the experimental melting temperatures. Screw dislocations are more difficult to generate than edge dislocations.