Experimental evidence of quantum tunnelling in TlBaCaCuO

Abstract

Experimental evidence of a crossover from a thermally to a non-thermally activated flux motion is reported for TlBaCaCuO. It was obtained by measuring the time decay of both zero-field-cooled and remanent magnetization. The measured relaxation rates at low temperature are in good agreement with the prediction of the quantum collective creep theory for anisotropic superconductors in the low-field-single-vortex pinning.