Enhancement of magnetic pinning in liquid phase sintered YBCO

Liquid phase sintering of YBCO superconductor has been investigated using 900 deg. C- and 950 deg. C-calcined precursors. Magnetic hysteresis, i.e. critical current density (Jc), is enhanced at elevated magnetic fields for the samples with the 900 deg. C-calcined precursor of fraction more than 80%. Jc increases steeply as fraction of 900 deg. C-calcined precursor increases from 80% to 100%, which is coincident with anomalous grain growth in the samples. The samples showing Jc enhancement compose of rather rectangular grains with length more than 100 μm, whereas grains of the samples showing no enhancement are rather round and a few tens of μm in diameter. Structural developments with fraction of the precursor and oxygenation behavior suggest that low angle grain boundary pinning is observed in the liquid phase sintered samples