SINGLE-CRYSTAL GROWTH OF ND2-XCEXCUO4 AT LOW-OXYGEN PRESSURE IN AMBIENT ATMOSPHERE

Nd1.85Ce0.15CuO4 single crystals of improved quality have been grown b y the TSFZ method at an oxygen partial pressure in ambient atmosphere of 0.2, 0.1, 0.08 and 0.01 atm. Superconductivity in the as-grown stat e has been observed in the crystals grown at 0.08 and 0.01 atm. The im provement of the Ce distribution has been achieved due to a decreased value of the Ce distribution coefficient at low oxygen partial pressur e in ambient atmosphere. The probability to obtain the same characteri stics of the superconducting transition in the as-gown state as that i n the crystals after post-growth high-temperature treatment seems to b e very low because of oxidation during the cooling of the grown crysta l from the crystallization temperature to room temperature.