Vortex-solid melting and depinning in superconducting Y-Ba-Cu-O single crystals irradiated by 3-MeV protons

The effects of controlled point defects on the vortex-solid melting and depinning of high-temperature superconductors are investigated by applying the critical scaling analysis to the vortex transport properties of 3-MeV-proton-irradiated Y-Ba-Cu-O single crystals. For magnetic fields ranging from 1 kOe to 90 kOe, the critical exponents of the melting transition are found to be universal, independent of the density of point defects. In contrast, material parameters associated with the vortex depinning are modified by the proton irradiations. © 1993 The American Physical Society.