Structure of CaMnO₃ in the range 10 K ≤ T ≤ 550 K from neutron time-of-flight total scattering

The local and average structure of the Ca endmember of the La Ca MnO series has been investigated. Neutron powder diffraction-based high real-space resolution atomic pair distribution function (PDF) analysis, yielding the local atomic structure, and the corresponding Rietveld analysis yielding the average crystal structure show that the two structural scales are in accord in this material, and that the MnO octahedral units are regular for all temperatures studied. Quantitative values of structural parameters are reported for a wide temperature range, important for both experimental and theoretical considerations of hole and electron doped branches of the rich phase diagram of La Ca MnO.