Variation of the enhancement mechanism in the critical current density of Cu-doped Mg[B.sub.2] samples sintered at different temperatures

The 3 at.% Cu-doped Mg[B.sub.2] samples are prepared at both low temperature and high temperature. The mechanism of enhancement in the [J.sub.c] of the Cu-doped Mg[B.sub.2] samples has varied distinctly from the grain-boundary pinning to the possible Mg[Cu.sub.2] nanoinclusions pinning as the sintering temperatures increases from low temperature to high-temperature.