Comment on “Temperature dependence of the second magnetization peak in a deoxygenatedYBa2Cu3O6.65single crystal”

Abstract

Measuring magnetic relaxation and hysteresis of a deoxygenated Y-123 single crystal with ${T}_{c}=62.5 \mathrm{K},$ Salem-Sugui, Jr. and coworkers [Phys. Rev. B 60, 102 (1999)] analyze the fishtail effect (FE) in a broad temperature range, 1.8 to 60 K. They interpret their experimental data at temperatures above 5 K as a crossover from elastic to plastic creep, which causes the fishtail peak. At low temperatures, below 5 K, they see evidence for plastic creep even below the FE maximum. Their experiment can be, however, alternatively explained in terms of a thermally activated flux creep [Perkins et al., Phys. Rev. B 51, 8513 (1995)] affected at low temperatures by self-field effects.