Superconducting Tl‐Ba‐Ca‐Cu‐O films by sputtering

Superconducting Tl‐Ba‐Ca‐Cu‐O thin films 0.2–1.0 μm thick have been prepared on MgO(100) and SrTiO3(100) substrates by dc diode sputtering using a single oxide target. Films containing primarily the Tl2Ba2Ca1Cu2O8 phase were obtained with a Tc (R=0) at 102 K and a transport Jc of 104 A/cm2 at 90 K. For the nearly pure phase Tl2Ba2Ca2Cu3O10 films, the Tc’s (R=0) are higher at 116 K and the transport Jc’s at 100 K are of 105 A/cm2. Both types of films show a strong preferred orientation with the c axis perpendicular to the film plane. The rocking curve of the Tl2Ba2Ca2Cu3O10 films is 0.32° wide and the typical grain size is over 10 μm.