Study of phase components of La1.5Ca1.5Mn2O7

The manganate with nominal composition La1.5Ca1.5Mn2O7, which is regarded a s a single-phase compound with layered perovskite structure in the literatu re, was prepared using a standard ceramic process. The structures and morph ology of the manganate were investigated by x-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy, and energy-disper sive x-ray microanalysis. However, no direct evidence of layered Sr3Ti2O7-t ype structure was observed in TEM experiments; instead, we observed multiph ase mixtures of an orthorhombically distorted perovskite phase as majority and cubic perovskite phase as minority, as well as a small amount of calciu m oxide. The measured magnetic and transport properties of this manganate a rise mainly from the presence of hole-doped multiphase perovskite manganate s. These physical properties demonstrated again the correctness of our phas e component analysis.