Effects of Isovalent Substitutions and Argon Heat Treatment on the Structural and Superconducting Properties of Y \(_{0.5}\) Ln \(_{0.5}\) SrBaCu \(_3\) O \(_{6+\delta }\)

The majority of extensive research efforts in solid-state physics have been directed toward studying the high \(T_c\) superconducting cuprates since 1986. It is well known that the physical properties of these compounds are closely linked to their preparation conditions. In high \(T_c\) , superconductivity is carried by positive charges (holes) on the strongly correlated CuO \(_2\) planes. The electronic states of the CuO \(_2\) planes are sensitive and influenced by structural, electrical, and magnetic characteristics, such as the size of the ionic radius, the applied magnetic field, valence, the distribution of surrounding ions, and the oxygen content. Moreover, all these characteristics are strongly influenced by the thermal treatments applied during the sample preparation. Particularly, when Ln is a rare earth element, such as Eu, Sm, and Nd, various effects are expected due to the large ionic radius of Ln ions compared to Y.