| Summary: | Superconductivity has been investigated in the system Y(Ba1-xSrx)2Cu4O8 (0 ≤ x ≤ 0.5). The samples were prepared by triethylammoniaoxalate coprecipitation at ambient oxygen pressure. The superconducting transition temperature, Tc, increased from a value of 85 K (x = 0) to 90 K (x = 0.1 - 0.2) and then decreased to 64 K at x = 0.5. For compositions beyond the solubility limit (x = 0.3), the magnitude of dTc dx was high, ca. 45 K from 0.3 to 0.5. The maximum Tc, 90 K, recorded from samples in the range x = 0.1 ∼ 0.2, were confirmed by magnetization measurements. These results are in contrast to those obtained from the Y(Ba1-xSrx)2Cu3O7 system, in which Tc decreased monotonically from 93 to 82 K for 0 ≤ x ≤ 0.5. © 1991.
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