Universality, critical dynamics, and vortex diffusion in amorphous Mo3Si films and YBa2Cu3O7 single crystals

Evidence of a vortex-glass transition in amorphous Mo3Si films on sapphire is manifested by the universal critical exponents (ν2/3,z3) obtained from dc electrical transport measurements. The exponents are consistent with those found in YBa2Cu3O7 single crystals with random point defects, indicating that the vortex-galss transition in both systems belongs to the same universality class. In contrast, ac transport measurements from 100 Hz to 3 MHz suggest that the dominant vortex dynamics in amorphous Mo3Si thin films is diffusion, and that in YBa2Cu3O7 single crystals it is the critical relaxation of thermally induced dislocations. © 1993 The American Physical Society.