Characterization of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7- delta </sub> single crystals grown from charges containing silver nitrate
D K Aswal; S K Gupta; S C Gadkari; K D S Mudher; L C Gupta; S C Sabharwal; M K Gupta; D K Aswal; Div. of Tech. Phys. & Prototype Eng., Bhabha Atomic Res. Centre, Bombay, India; S K Gupta; Div. of Tech. Phys. & Prototype Eng., Bhabha Atomic Res. Centre, Bombay, India; S C Gadkari; Div. of Tech. Phys. & Prototype Eng., Bhabha Atomic Res. Centre, Bombay, India; K D S Mudher; Div. of Tech. Phys. & Prototype Eng., Bhabha Atomic Res. Centre, Bombay, India; L C Gupta; Div. of Tech. Phys. & Prototype Eng., Bhabha Atomic Res. Centre, Bombay, India; S C Sabharwal; Div. of Tech. Phys. & Prototype Eng., Bhabha Atomic Res. Centre, Bombay, India; M K Gupta; Div. of Tech. Phys. & Prototype Eng., Bhabha Atomic Res. Centre, Bombay, India
Журнал:
Superconductor Science and Technology
Дата:
1995-09-01
Аннотация:
Single-crystal growth of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7- delta </sub> has been studied using starting charges containing known amounts of Ag in the form of AgNO<sub>3</sub>. The as-grown crystals are found to undergo a sharp transition to the superconducting state at 90 K, showing that the addition of AgNO<sub>3</sub> facilitates their oxygenation. The measured room-temperature resistivities, both in plane ( rho <sub>ab</sub>) and out of plane ( rho <sub>c</sub>), for the grown crystals are found to be the lowest among the values reported so far. The anisotropy in resistivity ( rho <sub>c</sub>/ rho <sub>ab</sub>) at 300 K is found to be roughly one-half of the value measured for the crystals grown from charges free from AgNO<sub>3</sub>. 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.
463.5Кб