Vortex phases and dynamics in high-temperature and conventional amorphous superconductors

The vortex phases and dynamics of high-temperature and conventional amorphous superconductors are investigated over a broad frequency range. A second-order vortex-solid melting transition in both YBa2Cu3O7 single crystals with random point defects and amorphous Mo3Si films is manifested by a set of universal critical exponents (ν≈ 2 3 and z≈3) from both ac and dc transport as well as ac magnetic susceptibility measurements. In contrast, the melting transition in YBa2Cu3O7 single crystals with correlated columnar defects is found to be consistent with a Bose-glass phase transition characterized by a different set of critical exponents (ν⊥≈ 1 2 and z′≈4). © 1993.