[Magnetic properties and transport behaviors in double doped La(0.67+1.33x)Sr(0.33-1.33x)Mn(1-x)Mg(x)O3 system].

The M-T curves, M-H curves, ESR curves, infrared spectrum, Raman spectrum, rho-T curves and MR-T curves of La(0.67+1.33x)Sr(0.33-1.33x)Mn(1-x)Mg(x)O3 (0.00 < or = x < or = 0.25) were studied. The experiment pointed out that all samples exhibit a paramagnetic-ferromagnetic (PM-FM) transition associated with metallic-insulating (MI) transition in the low doping region, which does not occur in the heavy doping zone. The authors suggest that this behavior is attributed to the difference between the Jahn-Teller distortion of the Mn3+ ion neighboring Mg2+ and that of the Mn3+ ion non-neighboring Mg2+, which is confirmed by the IR and Raman spectra. The anomalous transport behavior is dominated by the differerent Jahn-Teller distortion.