We present X-ray and magnetization results for the compound [Y0.75Ca0.25]SrBaCu3-x (PO4)xOy with 0.0 ≤ x ≤ 0.30 synthesized at normal pressure and temperature. X-ray diffraction patterns show that for x = 0.0 the compound crystallizes into an orthorhombic phase. For increasing x a tetragonal phase is obtained. The Rietveld method was used to refine lattice constants. The magnetization measurements show that the samples were all superconductors over a range of temperatures from 10 to 100 K. The diamagnetic transition temperature Tc decreases with increasing (PO4)3- concentration (Tc = 55 K for x = 0.0 and Tc = 35 K for x = 0.30).
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