TlBa2CaCu2O7(Tl‐1212) superconducting films 5000–6000 A˚ thick have been grown on LaAlO3(100) substrates using oxide precursors in a closed two‐zone thallination furnace. Tl‐1212 films can be grown with transition temperatures ∼100 K, and critical current densities measured by magnetization ofJcm(5 K)≳107A/cm2andJcm(77 K)≳105A/cm2. Processing conditions, substrate temperatures and Tl‐oxide source temperatures are found which result in smooth, nearly phase‐pure Tl‐1212 films. Variations in the respective temperature ramps of the Tl‐oxide zone and the substrate zone can greatly influence resulting film properties such as microstructure, morphology, superconducting transition temperature, and critical current density. ©1995 American Institute of Physics.