Effects of Fe doping on magnetic and transport properties in Pr0.75Na0.25MnO3

Single-phase polycrystalline perovskites Pr(0.75)Na(0.25)Mn(1-x) Fe(x)O(3) (0 <= x <= 0.30) were prepared by a sol-gel technique, which can reduce the volatilization of Na, and avoid the precipitation of manganese oxide. The effects of Fe doping at the Mn site upon the charge and the magnetic order in Pr(0.75)Na(0.25)WO(3) have been investigated combining magnetic and transport properties measurements. The results show that for low temperatures long range charge order (CO) is weakened even at doping concentration as low as 2%. The ferromagnetic (FM) fraction increases with increase in the Fe doping for x <= 5%, and decreases by further Fe doping. This complex behavior is interpreted in terms of the competition between geometric effect (size of the dopant) and the, effect of electronic configuration of the dopant. The steplike metamagnetic transition for the x <= 5% samples is observe and the origin is ascribed to the phase transition from CO antiferromagnetic (AFM) phase to FM phase in a phase separation scenario. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim