A NEW TECHNIQUE FOR THE GROWTH OF SUPERCONDUCTING YBA2CU3O6+DELTA CRYSTALS COMPLETELY SEPARATED FROM FLUX

Growth of completely flux-separated YBa2Cu3O6+delta (referred to as 123 phase) crystals using a novel technique is described. The technique employs a modification of the seed pulling method commonly used in crystal growth. The crystals are grown in the temperature range of 960-1000-degrees-C using a BaCuO2 flux. A 123 to flux ratio of 1:5 is maintained. Photographs of the crystals and photomicrograph of the surfaces are presented to show complete flux-separation of the crystals measuring 6 mm x 3 mm x 1 mm. The Raman spectra recorded on the as-grown crystals show that they are in the tetragonal phase. Magnetic susceptibility measurements on crystals annealed in an oxygen atmosphere show a superconducting transition starting at 71 K. The present technique offers a possibility of growing large, completely flux-separated crystals of 123 for superconductivity research.