Growth and comparison of single crystals and polycrystalline brownmillerite Ca2Fe2O5

Brownmillerite Ca2Fe2O5 is a mixed ionic electronic material with interesting electrical properties. In this report, the properties of Ca2Fe2O5 single crystals are compared with bulk polycrystalline Ca2Fe2O5 samples. Powder X-ray diffraction (PXRD), Scanning electron microscopy, Optical microscopy and Energy dispersive Xray spectroscopy (EDX) have been performed on the as prepared samples. XPS full survey spectra confirm the presence of constituent elements and reveal the peak binding energy of calcium, iron and oxygen. EDX was also used to trace the distribution of constituent elements. Images of crystal surfaces and interiors by polarized optical microscopy have been presented.