%0 Journal Article
%T Quantum Creep in Y_{1-x}Pr_{x}Ba_{2}Cu_{3}O_{7}$ Crystals: Magnetic Relaxation and Transport
%A T. Stein
%A G. A. Levin
%A C. C. Almasan
%A D. A. Gajewski
%A M. B. Maple
%J Physics
%D 1999
%I arXiv
%R 10.1103/PhysRevLett.82.2955
%X We report transport and magnetic relaxation measurements in the mixed state of strongly underdoped Y_{1-x}Pr_{x}Ba_{2}Cu_{3}O_{7} crystals. A transition from thermally activated flux creep to temperature independent quantum flux creep is observed in both transport and magnetic relaxation at temperatures T * 5 K. Flux transformer measurements indicate that the crossover to quantum creep is preceded by a coupling transition. Based on these observations we argue that below the coupling transition the current is confined within a very narrow layer beneath the current contacts.
%U http://arxiv.org/abs/cond-mat/9902076v2