Magnetic Transformations in Phase-Separated Manganite La_0.60Sr_0.35Ce_0.05Mn_0.95Со_0.05O_3+γ

The results of an experimental study of the magnetic properties of La_0.60Sr_0.35Ce_0.05Mn_0.95Со_0.05O_3+γ polycrystalline manganites produced using ceramic technology are presented. According to X-ray and electron microscopy studies, the samples are single phase, have a rhombohedral structure at 300 K, and are characterized by microdistortions and modulated crystallite structures. At temperatures below 140 K, the process of nucleation of the orthorhombic phase begins, and at 90 K, two phases are detected by X-ray diffraction: orthorhombic (space group Pnma) and rhombohedral (R \(\bar {3}\) c). Magnetometry reveals three temperatures of ~320, 220, and 130 K, at which the magnetic properties of the material change, the latter being characterized by a decrease in the magnetization of the manganite. Magneto-optical imaging makes it possible to identify these transitions with the appearance of magnetic-phase separation of the material, which is associated with inhomogeneities in the composition and structure, and to study the kinetics of phase nucleation.