Stoyanova-Ivanova A.K.Nedeltcheva T.K.Vladimirova L.K.2024-07-102024-07-102024-07-102024-07-102005-01-011644-36241644-362410.2478/bf02479273SCOPUS_ID:27444447734https://rlib.uctm.edu/handle/123456789/107The oxygen stoichiometry in R1-xCaxBa2 Cu3Oy (R = Eu, Er, Gd; x = 0, 0.2, 0.25, 0.3) superconducting bulk samples was determined spectrophotometrically. The dependence of the critical temperature on the y-oxygen coefficient and the x-coefficient of the included calcium was studied. © Central European Science Journals. All rights reserved.enArticle