Magneto-Electric Properties of LaMnO3 with Monovalent Na Element Doping at A Site

By measuring M-T curves and R-T curves of the samples La1-xNaxMnO3 (x=0.05, 0.10, 0.15, 0.20, 0. 25, 0.33), the influence of Na doping at La site on the magneto-electric properties was investigated. Results show that, Curie temperature TC increases and paramagnetic-ferromagnetic transition becomes steeper with increasing of Na content; all samples exhibit a paramagnetic-ferromagnetic transition associated with metal-insulator transition whereas the values of resistance decrease with the doping concentration increasing. The change of the magneto-electric properties originates from double-exchange function in Mn3+-O-Mn4+ and static Jahn-Teller distortion as well as the change of tolerance factor caused by increasing of the doping concentration.