Refinement of the crystal structural parameters of La_2/3Ca_1/3MnO₃ using quantitative convergent-beam electron diffraction

Crystal structural parameters (seven positional parameters and four isotropic Debye–Waller factors) of La_2/3Ca_1/3MnO₃ have been refined using the quantitative convergent-beam electron diffraction (QCBED) method. Using intensity information of many higher-order Laue-zone reflections simul­taneously is essential to refine structural parameters accurately. The effective global optimization algorithm was used to avoid the problems of input values and local minima. The fittings of the differential coefficients of one-dimensional experimental intensities and theoretical ones calculated by the dynamical diffraction theory were carried out with the normalized Euclidean distance criterion. Thus, all of these improve the accuracy and reliability of the analysis. The calculated results with the refined parameters agree with the experiments. The refined parameters also agree with the Rietveld refinement results of neutron diffraction.