| 摘要 |
There is disclosed an improved process for preparing a superconducting composition having the formula MBa2Cu3Ox wherein M is selected from the group consisiting of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; x is from about 6.5 to about 7.0; said composition having a superconducting transition temperature of about 90 K.; said process consisiting essentially of mixing ba(NO3)2, M2O3 and CuO in an atomic ratio of M:Ba:Cu of about 1:2:3 to form a precursor powder and heating the precursor powder in an oxygen-containing atmoshpere at a temperature from about 875 DEG C. to about 950 DEG C. for a time sufficient to form MBa2Cu3Oy, where y is from about 6.0 to about 6.4; and maintaining the Mba2Cu3Oy in an oxygen-containing atmosphere while cooling for a time sufficient to obtain the desired product.
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