La_(0.7)Ca_(0.3)MnO_(3)(LCMO)thin films have been grown on MgO substrate using the metal organic deposition process.The lattice mismatch between LCMO and MgO is relatively large around 8.14% imposing large inplane-ten...La_(0.7)Ca_(0.3)MnO_(3)(LCMO)thin films have been grown on MgO substrate using the metal organic deposition process.The lattice mismatch between LCMO and MgO is relatively large around 8.14% imposing large inplane-tensile strain and out-of-plane-compressive strain on the film.Hence the structural,microstructural and electrical properties have been found to be strongly correlated to the strain degree and relaxation.Cross-section transmission electron microscopy observations demonstrate the presence of microstructural defects due to the large lattice mismatch between the LCMO and MgO.In addition to structural and microstructural defects,X-ray diffraction and Raman spectroscopy measurements show the existence of a minor phase of MnO in the film.Magnetization versus temperature measurement show a relatively low Curie temperature around 75 K.The electrical behavior is found to be semiconducting over a large temperature interval.The electrical transport mechanisms have been investigated using the small polaron hopping and variable range hopping models and correlated to their microstructural properties.展开更多
文摘La_(0.7)Ca_(0.3)MnO_(3)(LCMO)thin films have been grown on MgO substrate using the metal organic deposition process.The lattice mismatch between LCMO and MgO is relatively large around 8.14% imposing large inplane-tensile strain and out-of-plane-compressive strain on the film.Hence the structural,microstructural and electrical properties have been found to be strongly correlated to the strain degree and relaxation.Cross-section transmission electron microscopy observations demonstrate the presence of microstructural defects due to the large lattice mismatch between the LCMO and MgO.In addition to structural and microstructural defects,X-ray diffraction and Raman spectroscopy measurements show the existence of a minor phase of MnO in the film.Magnetization versus temperature measurement show a relatively low Curie temperature around 75 K.The electrical behavior is found to be semiconducting over a large temperature interval.The electrical transport mechanisms have been investigated using the small polaron hopping and variable range hopping models and correlated to their microstructural properties.
