Magnetoresistance studies on barium doped nanocrystalline manganite

Abstract

An energetically attractive, simple, fast and a novel low temperature (300• C) solution combustion route for the synthesis of crystalline and homogeneous nanoparticles of lanthanum barium manganese oxide La 0.9 Ba 0.1 MnO 3+δ (LBMO) is reported. Formation and homogeneity of the solid solutions have been confirmed by powder X-ray diffraction (PXRD) and energy dispersive X-ray analysis (EDS) respectively. The Rietveld analysis shows both as-formed as well as calcined samples are in cubic phase with space group pm3m. The microstructure and agglomerated particle size of the compounds are examined by scanning electron microscope. Infrared spectroscopy revealed that both Mn O Mn bending mode and Mn O stretching mode are influenced by calcination temperature. The magnetoresistance measurement on sintered LBMO pellet exhibits a broad metal-insulator transition (T M-I ) at around 228 K. At 1 T applied magnetic field, LBMO shows magnetoresistance (MR) of 10%, whereas for 4 and 7 T, the negative magnetoresistance values are in the range 51 and 59% respectively at T M-I . The experimental resistivity data of the present investigation are fitted to a simple empirical equation in order to understand conduction mechanism in this compound.

The effect of citric acid to metal nitrates molar ratio on sol–gel combustion synthesis of nanocrystalline LaMnO3 powders

“…3b). On the other hand, a significant spectroscopic band at about 600 cm −1 appears corresponding to the stretching mode involving the internal motion of a change in length of the Mn-O-Mn or Mn-O bond [17]. The band at 1465 cm −1 with a shoulder at 1370 cm −1 can be assigned to the C-O stretching of unidentified carbonates resulting from the decomposition of the citrates.…”

Thermal hysteresis in electrical transport of charge ordered La0.5Ca0.5MnO3 manganites

“…However, this is mainly the situation for the thin films and single crystals [5]. For example see a recent report, where the metal-insulator transition temperature (T MI ) with peak resistivity is seen for bulk La 0.5 Ca 0.5 MnO 3 [11]. The CO state is represented in terms of a sudden increase in resistivity around T CO (charge ordered transition temperature) in (T) plots and thus producing the kink in the resistivity curve.…”

Synthesis and electrical properties of nanocrystalline Ca1−xEuxMnO3±δ (0.1≤x≤0.4) powders prepared at low temperature using citrate gel method

“…Several techniques based on solution chemistry methods have been attempted for the preparation of fine powders of the perovskite oxide materials using low processing temperatures in comparison with the conventional solid-state reaction process, leading to a homogeneous, highly reactive and nanosized powder [18,[22][23][24][25][26][27].…”