Local tetragonal distortion in La 0.7 Sr 0.3 MnO 3 strained thin films probed by x-ray absorption spectroscopy

摘要: We report on an angular resolved x-ray absorption spectroscopy study of ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ thin films epitaxially grown by pulsed laser deposition slightly mismatched substrates which induce tensile or compressive strains. XANES spectra give evidence tetragonal distortion within the ${\mathrm{MnO}}_{6}$ octahedra, with opposite directions for and Quantitative analysis has been done a model reflecting strain established. EXAFS data collected in plane substrate confirm change $\mathrm{Mn}\text{\ensuremath{-}}\mathrm{O}$ average bond distance increase $\mathrm{Mn}\text{\ensuremath{-}}\mathrm{Mn}$ length matching enlargement cell parameter. From these results we conclude that there is no significant $\mathrm{Mn}\text{\ensuremath{-}}\mathrm{O}\text{\ensuremath{-}}\mathrm{Mn}$ angle. Our observations conflict scenarios this angle main driving parameter sensitivity manganite properties to external strains suggest octahedra plays key role modification transport magnetic properties.