Synthesis and Magnetic Resonance of Lanthanum Manganites Doped with Potassium Ions

Manganites doped with potassium ions La 1 – x K x MnO 3 , where х = 0.0, 0.1, and 0.15, have been obtained by extraction-pyrolytic method at low temperature. The compounds have been studied by X-ray powder diffraction, electronic paramagnetic and ferromagnetic resonances. Unit cell parameters of La 1 – x K x MnO 3 samples have been calculated. According to magnetic resonance spectroscopy, La 1 – x K x MnO 3 exhibits phase delamination into paramagnetic and ferromagnetic phases. The fraction of the latter phase increases when temperature decreases. The temperature of transition from paramagnetic into ferromagnetic phase (Curie temperature, T C ) for La 1 – x K x MnO 3 is –17.4, –13.7, and –4.8°С at х = 0.0, 0.1, and 0.15, respectively. The reason of symbate change in T C and potassium ion concentration in La 1 – x K x MnO 3 is supposed to be the change in the content of ferromagnetic pairs Mn 3+ –О 2– –Mn 4+ in the manganites.