Characterization of YBaCu3O7-δ single crystals grown from charges containing silver nitrate

Single-crystal growth of YBa2Cu3O7-δ has been studied using starting charges containing known amounts of Ag in the form of AgNO3. The as-grown crystals are found to undergo a sharp transition to the superconducting state at 90 K, showing that the addition of AgNO3 facilitates their oxygenation. The measured room-temperature resistivities, both in plane (ρab) and out of plane (ρc), for the grown crystals are found to be the lowest among the values reported so far. The anisotropy in resistivity (ρc/ρab) at 300 K is found to be roughly one-half of the value measured for the crystals grown from charges free from AgNO3. The angular dependence of transport critical current for the doped crystals has been measured at 82 K and for an applied magnetic field of 0.9 T. The results have been analysed using the existing theoretical models. (author)