TlSr2CaCu2Oy template for the growth of superconducting Tl(Ba, Sr)2Ca2Cu3Oy thin films on CeO2 buffered sapphire

Thin films of Tl(Ba, Sr)2Ca2Cu3Oy superconductor have been grown on CeO2 buffered r-cut sapphire substrate with the use of a template TlSr2CaCu2Oy by the amorphous phase epitaxy method. By using this template containing Sr, we have overcome the problem of chemical reactions between Ba and Ce present in the superconducting and buffer layers, respectively, at the normal processing temperatures of 840–890 °C. Films grown by this method have an excellent c-axis orientation as well as in-plane alignment with the TlSr2CaCu2Oy template, which in turn is aligned with the CeO2 layers. These films have superconducting critical temperature values up to 104 K and critical current density values as high as 1 MA cm−2 at 77.3 K and 0 T.