C_-axis oriented (Hg,Ti)-based superconducting films with T_c≥125 K

Authors

F. Foong, University of Nebraska - Lincoln
B. Bedard, University of Nebraska - Lincoln
Q.L. Xu, University of Nebraska - Lincoln
Sy_Hwang Liou, University of Nebraska-LincolnFollow

Date of this Version

February 1996

Comments

Published by American Institute of Physics. Appl. Phys. Lett., 68, 1153(1996). ©1996 American Institute of Physics. Permission to use. http://jap.aip.org/jap/.

Abstract

Thin films with mostly (Hg,Tl) ₁Ba₂Ca₃Cu₂O_{8+ δ} [(Hg,Tl)-1223] phase have been fabricated by radio frequency magnetron sputtering of precursor films and post-annealing method. The doping of a small amount of thallium in the film is helpful to the formation of the three-layer CuO₂ compound. These films have a highly oriented structure with the c-axis perpendicular to the film surface. Resistivity measurements show that the films after annealing at 300 °C for 1 h in O₂ have the superconducting transition temperature of T_c (onset)=133 K and T_c (zero)=127 K. Scanning electron micrographs of the film reveal platelike micrometer-size grains coalesce to cover the substrate surface.