Relative $K$ x-ray intensities of $Mn$ in $Mn$, $MnO_{ 2}$, $LaMnO_{ 3}$ and $La_{ 0.7}B_{ 0.3}MnO_{ 3}$ ($B$ = $Ca$, $Sr$, and $Ce$) systems have been measured following excitation by 59.54 keV $\gamma$-rays from a 200 mCi $^{ 241}$Am point-source. The measured results for the compounds deviate significantly from the results of pure $Mn$. Comparison of the experimental data with the multiconfiguration Dirac-Fock (MCDF) effective atomic model calculations indicates reasonable agreement with the predictions of ionic model for the doped { manganites except} that the electron doped $La_{ 0.7}Ce_{ 0.3}MnO_{ 3}$ and hole doped $La_{ 0.7}Ca_{ 0.3}MnO_{ 3}$ compounds show some small deviations. The results of $MnO_{ 2}$ and $LaMnO_{ 3}$ deviate considerably from the predictions of the ionic model. Our measured $K\beta/K\alpha$ ratio of $Mn$ in $La_{ 0.7}Ca_{ 0.3}MnO_{ 3}$ cannot be explained as a linear superposition of $K\beta/K\alpha$ ratios of $Mn$ for the end members which is in contrast to the recent proposal by Tyson et al. from their $Mn$ $K\beta$ spectra.
Categories: cond-mat.mtrl-sci