Study of magnetic phase transformations in Nd1-xBaxMnO3-δ (0 ≤ x ≤ 0.50) system depending on conditions of production

The studies on the crystal structure magnetic and electric properties of the monocrystals (0.23 ≤ x ≤ 0.34) and polycrystals of the Nd1-xBaxMnO3-δ solid solutions system are carried out. It is determined that the maxim Curie temperature (TC) for the samples, obtained in the air does not exceed 150 K, whereas the TC for the polycrystalline samples from the concentration interval 0.34 ≤ x ≤ 0.50, obtained in the reduction medium (gaseous mixture of argon and carbon oxide), increases up to 320 K. The hypothetical magnetic phase diagrams of the solid solutions system under consideration are plotted in dependence on the barium concentration and way of its acquisition. It is supposed, that sharp increase in the TC of the polycrystalline samples, obtained in the reduction medium, is caused by the extended defects and microstresses appearance on the crystalline lattice