Synthesis and Magnetic Resonance of Lanthanum Manganites Doped with Potassium Ions

Manganites doped with potassium ions La1 – xKxMnO3, 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 La1 – xKxMnO3 samples have been calculated. According to magnetic resonance spectroscopy, La1 – xKxMnO3 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, TC) for La1 – xKxMnO3 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 TC and potassium ion concentration in La1 – xKxMnO3 is supposed to be the change in the content of ferromagnetic pairs Mn3+–О2––Mn4+ in the manganites.