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Growth of YBa 2 Cu 3 O x Single Crystals with Superconducting Transition above 90 K

1987; Institute of Physics; Volume: 26; Issue: 9A Linguagem: Inglês

10.1143/jjap.26.l1425

1347-4065

Humihiko Takei, Hiroyuki Takeya, Yasuhiro Iye, T. Tamegai, Fumiko Sakai,

Superconductivity in MgB2 and Alloys

Single crystals of high-temperature superconductor YBa 2 Cu 3 O x have successfully been prepared using a CuO flux method. Two types of crystals of a mm-size are obtained: irregular blocks with the (001) habit and thin plates with the well-developed (001) plane. EPMA shows that the ratio Y/Ba/Cu is 1.0/1.9/2.9 and no apparent difference in metal composition is observed between the two. Electrical resistivity measurements show that the block crystals are metallic and exhibit a sharp superconducting transition at 91.3 K, whereas the plates are semiconducting and show no superconducting behavior above 4.2 K.