Through careful processing, single‐phase material of the (Bi,Pb)‐Sr‐Ca‐Cu oxide withTc∼111 K has been synthesized. Powder x‐ray diffraction patterns are employed to verify that repetitive grinding and sintering leads to the virtual disappearance of peaks corresponding to the other superconducting polytypoids of this complex system. The dimensions of the face‐centered pseudotetragonal unit cell are determined to be 5.41×5.40×37.13 A˚3. The Meissner and shielding effects shown by dc magnetic susceptibility measurement of the bulk and pulverized specimens at various stages of processing demonstrate that the proper high‐Tcsuperconductor can be synthesized in single‐phase form.
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