We report the phase formation and superconductivity in [Y1-xCax]SrBaCu2.80(BO3) 0.20Oy with 0.10≤ x ≤ 0.50 prepared at normal pressure and temperature. The X-ray diffraction pattern shows that all samples have a tetragonal P4/mmm structure, indicating that the BO3 groups were incorporated in the structure. The ZFC magnetization versus temperature measurements under an applied field of 10 Oe using a SQUID magnetometer, show that the materials are superconductors, with Tc ≈ 77K, almost independently of the Ca content. The observed differences are related to the volume fraction of Meissner effect. In the temperature range 100-300K all samples show a typical Curie - Weiss behavior, under an applied high field of 20 KOe. © 2000 Elsevier Science B.V. All rightsreserved.
|Original language||American English|
|Number of pages||2|
|Journal||Physica C: Superconductivity and its Applications|
|State||Published - 1 Dec 2000|