Abstract: By measuring M-T curves, ESR curves, ρ-T curves and MR-T curves of the samples,
the influences of Fe doping (x=0.05, 0.10, 0.20, 0.30, 0.40) upon magnetic
and electric properties of LaMnO₃ were studied. The experimental results indicate that all samples undergo the transition from paramagnetism to ferromagnetism at TC. For the doped samples, there is a paramagnetic-ferromagnetic (PM-FM) transition but there is no insulator-metal(IM) transition. The results are attributed to double exchange interaction between Fe3+ ions and Mn3+ ions and Jahn-Teller effects.

Key words: colossal magnetoresistance effect, magnetic structure, transport behaviors, double exchange