LaMnO3 Thin Films Research Articles

Resonant X-ray scattering and cooperative Jahn–Teller effect in LaMnO3 thin films

Abstract Epitaxial thin films of LaMnO3 were grown on MgO and SrTiO3. The cooperative Jahn–Teller transition occurred at different temperatures for the two films. It is shown that the intensity of the resonant (1 0 0) peak at the Mn K-edge is proportional to the 3 2 power of the orthorhombic strain for both films at all temperatures below the transition. This provides an evidence in favor of the band effect in accounting for the resonant scattering in LaMnO3. A significant intensity difference in the resonant scattering in the two films is pointed out.

Composition and Growth-Temperature Effect on the Microstructure of Epitaxial La1−x Srx MnO3 (x = 0, 0.2) Thin Films on (001) LaAlO3

La0.8Sr0.2MnO3 (LSMO) and LaMnO3 (LMO) thin films epitaxially grown on (001) LaAlO3 substrate at 700 and 800°C were studied using cross-section and plan-view transmission electron microscopy. In both LSMO and LMO films deposited at 700°C, a two-layered structure was observed: a continuous cubic perovskite layer epitaxially grown on the substrate followed by epitaxially grown orthorhombic column nanostructures. The orthogonal nano columns in LSMO were very well defined with a narrow size distribution. The LMO films exhibited a somewhat distorted orthogonal shape for the nanostructured columns and a wider size distribution. LSMO and LMO epitaxial films deposited at 800°C consisted of only a continuous single layer of cubic perovskite. These results reveal that formation of epitaxial column nanostructures in the La1-xSrxMnO3 thin films strongly depends on the growth temperature. Sr substitution on La sites in La1-xSrxMnO3 can improve uniformity of column size distribution and perfection of the orthogonal shape of nano columns.

Preparation, structural and magnetic characterisation of RF-sputtered La1−xNaxMnO3±δthin films manganites

In this paper we report about the synthesis and characterisation of the structure and magnetic properties of sodium doped LaMnO3 thin films prepared by means of RF-magnetron sputtering. The synthesis was realised at two different substrate temperatures (500 and 700 °C) and with different gas chamber compositions. The role of oxygen content variation has been checked by annealing the thin films at different oxygen partial pressures. By reducing the oxygen content an increase of the distortion in the film has been observed together with a reduction of the Curie temperatures. Films with high Curie temperatures (250 K) have been prepared at 700 °C in pure argon.

EFFECTS OF IN-PLANE STRAIN ON MAGNETISM IN LaMnO3 THIN FILMS

The effects of the in-plane strain on the magnetic properties of LaMnO3 thin films are calculated using an elastic energy expression and a tight binding Hamiltonian with electron-lattice coupling. Tensile uniaxial strain of the order of 2%, which is the order of the magnitude of those induced in thin films by lattice mismatch with substrates, is found to change the magnetic ground state from A-type antiferromagnetic state to purely antiferromagnetic state.

Effects of in-plane strain on orbital ordering and magnetism in LaMnO3 thin film

The effects of the in-plane strain on the orbital and magnetic properties of LaMnO3 thin films are calculated using an elastic energy expression and a tight-binding Hamiltonian with electron–lattice coupling. Tensile uniaxial strain of the order of 2%, which is the order of magnitude of those induced in thin films by lattice mismatch with substrates, is found to change the orbital state and magnetic ground state significantly.

Evidence of Anisotropic Thermoelectric Properties in La2/3Ca1/3MnO3 Thin Films Studied by Laser-Induced Transient Voltages

AbstractPulsed UV laser illumination of doped LaMnO3 thin films deposited on vicinal cut SrTiO3 [ STO ] substrates causes unexpected transient voltages at room temperature in remarkable analogy to those observed for intrinsically anisotropic YBa3Cu3O7−x, [YBCO] thin films. The experimental data for La2/3Ca1/3MnO3 [LCMO] thin films are consistent with the description of thermoelectric fields caused by off-diagonal elements of the Seebeck tensor. Systematic measurements of the dependence of the laser-induced signal on the geometry of the sample, the temperature and doping dependence suggest that the anisotropy of the Seebeck tensor is due to combination of long range co-operative Jahn-Teller distortions and substrate-induced biaxial strain effects.

Preparation and Characteristics of LaMnO3 Thin Film Electrode on YSZ by a Vapor-Phase Process

Abstract Dense and thin LaMnO3/YSZ/La0.85Sr0.15MnO3 cell was perpared by CVD-EVD process. The prepared LaMnO3 film was sufficiently uniform and dense, no pore or crack was observed in the LaMnO3 film. AC impedance measurements indicated that the electrode interface conductivity was linearly dependent on the electrode surface area. For dense and thin film electrode of LaMnO3, oxygen electrochemical reacion proceeded predominantly at the electrode surface region.

Preparation of LaMnO3 thin Film Electrode for Solid Oxide Fuel Cells by Vacuum Evaporation

Preparation of LaMnO3 thin Film Electrode for Solid Oxide Fuel Cells by Vacuum Evaporation