The main goal of this proposal is a detailed neutron powder diffraction (NPD) study of the La0.5Ba0.5Co1-xFexO3 compounds to clarify the crystal and magnetic structure transformations. The results of this study are supposed to find most probable model explaining the nature of the phase separation, small structural distortions and magnetic structure changes in the range of unusual phase transitions. The combination of neutron with X-ray powder diffraction data, magnetization studies and XAFS-spectroscopy results at the Co and Fe K-edges (ESRF, BM23 beamline) will give us an opportunity to analyze the crystal and magnetic structure changes of lattice parameters and local atomic (EXAFS Debye-Waller factor of Co-O bond) and electronic(valence & spin-state change of cobalt ions) structure distortions near Co ions in order to establish the most probable model explaining the correlation of the crystal and magnetic structure transformations as well as magnetic and transport properties in a wide temperature range.