0000000000953978
AUTHOR
Tord Claeson
Impact of granularity on transport properties of mechanically stressed La0.67Ca0.33MnO3 films
Abstract (La,Ca)MnO 3 is one of so called collosal magnetoresistive materials and it is of interest to correlate its transport properties to film growth in order to optimize its performance. Two-hundred nanometers thick (100)La 0.67 Ca 0.33 MnO 3 films were grown by laser ablation on (100)SrTiO 3 , (100)LaAlO 3 and (100)(LaAlO 3 ) 0.3 +(Sr 2 AlTaO 6 ) 0.7 substrates. The films were granular in structure with low angle boundaries between the grains. The volume of the unit cell was considerably smaller for films grown on a SrTiO 3 substrate than on LaAlO 3 . At temperatures higher than the one where the spins order, the strongest response of resistivity on temperature ρ ( T ) was measured for…
Temperature and electric field dependence of the permittivity of Ba0.9Sr0.1TiO3 films epitaxially grown on cuprate electrodes
Abstract Cuprate, high-temperature superconductors and perovskite ferroelectrics have similar crystal structures and chemical constituents and, therefore, it can be advantageous to deposit epitaxial trilayer capacitors with high-Tc electrodes and operate these at room temperature, well above the transition temperature Tc, in order to achieve a high dielectric constant, tunability, and relatively low microwave loss. Epitaxial heterostructures (200 nm)YBa2Cu3O7−δ/(600 nm)Ba0.9Sr0.1TiO3/(200 nm)YBa2Cu3O7−δ and (200 nm)NdBa2Cu3O7−δ/(600 nm)Ba0.9Sr0.1TiO3/(200 nm)NdBa2Cu3O7−δ were laser deposited on (100)LaAlO3 substrates. The relative dielectric permittivity e/e0 of Ba0.9Sr0.1TiO3 was in the ra…
Preparation and properties of Tl2Ba2CaCu2O8 thin films
Anex situ process has been developed to produce thin superconducting Tl2Ba2CaCu2O8 films. The properties of films grown on different substrates using different annealing regimes were studied. Critical temperatures of 103–107 K were measured on films prepared in a broad range of annealing temperatures on SrTiO3, LaAlO3, and Y-ZrO2 substrates. A critical current density,Jc, of 2×106 A/cm2 at 77 K was measured on LaAlO3. Film morphology was studied by SEM, AFM, and STM.