Vortex glass transition in a YBa 2Cu 3O 7− δ film with patterned pinning geometry

Abstract

We report on multiterminal transport measurement in YBa 2Cu 3O y films, where a vortex flow channel is artificially introduced in a strong pinning environment with columnar defects. The samples were prepared by partially masked heavy-ion irradiation. Two kinds of phase transitions with different transition temperatures, T VG and T BG, which correspond to the vortex glass transition and the Bose glass transition, are observed for the unirradiated region and the irradiated one, respectively. At high field, the situation of T VG< T BG, where the flux flow in unirradiated channel is confined between Bose glass solids of the irradiated region, is realized. The vortex velocity distribution is almost homogeneous inside the channel. Around the boundary, however, we find that the vortices flowing in the unirradiated channel drag the vortices of the Bose glass solid in the irradiated region.