Pan'kiv L. Magnetic and electrical properties of sodium substituted lantanum manganites

In dissertation, the investigation of impact of chemical composition and mechanical strain on the transformation of magnetic and electrical parameters of the bulk and thin film samples of sodium substituted lanthanum manganites is carried out. The correlation between structural and magnetic properties of polycrystalline bulk samples of La1-xNaxMnO3 (x = 0,08 - 0,16) is established. It is found that increasing of sodium concentration results in rise of Curie temperature and shift of temperature of electrical and magnetoresistance maxima toward higher temperatures. It is shown that the polycrystalline partially crystalized films of La0,84Na0,16MnO3 onto polycrystalline Al2O3 substrates, obtained at two different values of substrate temperature (Ts) 300 C and 500 C, are characterized by wide temperature region of transition from paramagnetic into ferromagnetic state. The transition to state with perpendicular magnetization is observed in the low-temperature region for the manganite films La0,84Na0,16MnO3, obtained onto single crystalline LaAlO3 (001) substrates, subjected to deformation of compression in the plane of the film.