Lowhyphen;temperature formation of epitaxial Tl2Ca2Ba2Cu3O10thin films in reduced O2pressure

摘要

Epitaxial Tl2Ca2Ba2Cu3O10films on (100) LaAlO3are prepared by posthyphen;annealing 2Tl:2Ca:2Ba:3Cu precursor films at 830ndash;860thinsp;deg;C in bartil;0.03ndash;0.15 atm of O2. These films (0.2ndash;1.1 mgr;m thickness) are smooth and shiny to the eye, and have a sharp zero resistance and onset diamagnetic transition temperature of 117ndash;121 K. Transport critical current densities of 1.6times;106A/cm2at 77 K and bartil;105A/cm2at 100 K are obtained for a 0.38hyphen;mgr;mhyphen;thick film in magnetic fields up to 100 Oe. Strong flux pinning at low temperatures is inferred from the weakhyphen;field dependence of the critical current density calculated from magnetic hysteresis loops. At 5 K, the best film has a magnetic critical current density of 9times;106A/cm2in zero field, decreasing gradually to 1.5times;106A/cm2in a 5hyphen;T field.