Synthesis of orthorhombic rare-earth manganite thin films by a novel chemical solution route (original) (raw)
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Synthesis and characterisation of La 1− x Na x MnO 3+ δ thin films manganites
Optimally sodium doped lanthanum manganite (LNMO) thin films have been grown onto differently oriented NdGaO 3 single crystals substrates by means of radio-frequency (RF)-magnetron sputtering technique, in order to investigate the role of the strain imposed by lattice mismatch on the magnetotransport properties. Films deposited onto NdGaO 3 (1 1 0) experiment a slight in-plane compressive strain that can be tuned by the thickness and allows to achieve colossal magnetoresistive effects. On the contrary, the change of the substrate orientation induces an in-plane tensile strain, making the film insulating. Above observations are explained by considering the effect of distortions of the Mn-O coordination polyhedra.
Hexagonal rare earth (R=Eu-Dy) manganites: XRD study of epitaxially stabilized films
Crystal Engineering, 2002
Epitaxial thin films of RMnO 3 (R=Sm, Eu, Gd, Dy) were prepared using liquid injection MOCVD and studied by XRD. The formation of high-temperature hexagonal polymorphic structure of DyMnO 3 and non-existing-as-bulk hexagonal EuMnO 3 , GdMnO 3 and SmMnO 3 (traces) was observed on ZrO 2 (Y 2 O 3) (111) substrates at 900°C due to epitaxial stabilization. For the thickness exceeding the critical one the oriented stable perovskite form grew on the hexagonal phase. Parallel deposition on perovskite or non-coherent substrates gave only the stable perovskite phase, epitaxially grown in the former case or oriented in the latter.
Solid State Ionics, 2004
In this paper, we report the results about the synthesis and characterization of optimally doped La 0.85 Na 0.15 MnO 3 thin films deposited onto SrTiO 3 (100), NdGaO 3 (100) and NdGaO 3 (110) for thickness ranging from 11 to 82 nm. The effect of the substrate nature and orientation and film thickness was investigated in order to optimize the physical properties of the films. We obtained very smooth films displaying magnetoresistance values greater than 70% for temperature near to room temperature which makes them appealing for applicative purposes. D 2004 Published by Elsevier B.V.
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Progress in Solid State Chemistry, 2005
Polycrystalline La 0.7 Sr 0.3 MnO 3 manganite thin films were grown on silicon substrates covered by SiO x amorphous native oxide. Unusual splitting of the manganite layer was found: on the top of an intermediate layer characterised by lower crystalline order, a magnetic robust layer is formed. Curie temperatures of about 325 K were achieved for 70 nm thick films. A strong room temperature XMCD signal was detected indicating high spin polarisation near the surface.
Thin films and superlattices of multiferroic hexagonal rare earth manganites
Philosophical Magazine Letters, 2007
Hexagonal YMnO 3 and HoMnO 3 as well as (YMnO 3 /HoMnO 3) 15 superlattices were grown on (111) ZrO 2 (Y 2 O 3) and (111) Pt/TiO 2 /SiO 2 /p-type (100)Si substrates. Epitaxial stabilization was used on the same substrates to grow DyMnO 3 or TbMnO 3 (which normally crystallize in an orthorhombic, perovskite-type, structure). All heterostructures were obtained oriented, with the c-axis of the hexagonal cell perpendicular to the substrate plane. This orientation is desired since it is the direction of the ferroelectric polarization in hexagonal manganites. The strain state of the films grown on conductive Pt electrodes, tracked by the evolution of the c parameter as a function of film thickness, was found to be completely different than the one obtained on YSZ. Such a study is important for future strain engineering in multilayers. Highresolution transmission electron microscopy on superlattices grown on (111)Pt indicates a high crystalline quality along the c-axis and sharp interfaces.
Journal of Materials Science, 2018
The results of fabrication of nanostructured La 1-x Sr x MnO 3 films grown by pulsed injection metalorganic chemical vapour deposition technique onto special disordered glass-ceramics substrate are presented. Two groups of films were produced in order to determine what would be their main physical properties when certain fabrication changes were introduced: (1) films with thicknesses in the range of 25-900 nm, which were grown at a temperature of 750°C; and (2) films having thicknesses of 400 nm, which were grown at different deposition temperatures ranging from 600°C up to 775°C in steps of 25°C. It was determined that the morphology and microstructure of the films depends on the thicknesses of these films and their deposition temperatures. The thinnest films (25 nm) grew mainly in amorphous phase, while the thicker films had well-pronounced structure made of column-shaped crystallites. These had average column widths of 40-65 nm, were spread throughout the whole thickness of the films, and were separated by 5-10-nm-thick grain boundaries. The influence of growth conditions on the colossal magnetoresistance effect in these films was studied in pulsed magnetic fields of up to 20 T. The dependences of the magnetoresistance on the magnetic flux density were analysed using modified Mott's hopping model. It was demonstrated that these nanostructured films behave as superparamagnetic materials with reduced magnetic properties due to disordered grain boundaries. The obtained results allow the tuning of the resistivity, magnetoresistance and the anisotropy of La 1-x Sr x MnO 3 manganite films, which were deposited onto glass-ceramic substrates, and thus to use them for the fabrication of high pulsed magnetic field sensors.