Effect of structure on the properties of La-deficient La0.54Ca0.32MnO3−δ manganite

X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) have been carried out in a La-deficient sample of La0.54Ca0.32MnO3. From the XRD pattern it was found that the crystal structure has been distorted by the deficiency in A (=La, Ca) position. The temperature dependence of EPR line intensity was successfully fitted by the exponential law based on the small polaron hopping model. High values of an activation energy (Ea=0.22eV) derived from EPR data are believed to relate to the above distortion, but EPR line-width, ΔHpp, and a slope, b, of the ΔHpp temperature dependence are not.