Combustion synthesis, characterization and metal–insulator transition studies of nanocrystalline La1−xCaxMnO3 (0.0≤x≤0.5)

Combustion synthesis and effect of LaMnO3 and La0.8Sr0.2MnO3 on RDX thermal decomposition

“…The band at 1637 cm −1 corresponds to the surfaceadsorbed oxygen species (O ad ) [15], and the bands at 614 cm −1 correspond to the stretching mode of the Mn-O-Mn or Mn-O bond [11]. These results showed that the adsorbed water or hydroxyl groups, surface-adsorbed oxygen exist on the surface of LaMnO 3 and La 0.8 Sr 0.2 MnO 3 .…”

“…However, the corresponding values for LaMnO 3 prepared by oxalyl dihydrazide and urea aqueous solution combustion methods are 12.5 m 2 /g [11], 5.6 m 2 /g [12], respectively; the values for La 0.8 Sr 0.2 MnO 3 obtained by citric acid combustion synthesis and the amorphous citrate process are 11.53 m 2 /g [13], 5.1 m 2 /g [14], respectively. Obviously, the values in this study are higher.…”

Studies on La0.67Ca0.33MnO3–SrTiO3 composites using two-phase model

“…This may be mentioned here that unit cell of LCMO consists of central Mn atom surrounded by six nearest neighbour oxygen ions in octahedral structure, which contains six vibrating modes, but only two of them are IR active. The first peak of this spectrum at ∼418 cm −1 corresponds to bending mode (v b ) of bond angle and the strong absorption peak at ∼592 cm −1 arises from stretching mode (v s ) of Mn-O bond which involves the internal motion of a change in bond length in MnO 6 octahedral and the band at about 592 cm −1 can be caused by the Jahn-Teller effect [12,18,23,24]. In IR spectra of STO two absorption peaks have been observed at ∼600 cm −1 and ∼425 cm −1 correspond to the Ti-O stretching modes, similar type of result has been found by Zhou et al [25] also.…”

Investigation of the structure and the magnetic behavior of nanostructure Ca1−Gd MnO3 (x=0.05; 0.1; 0.15; 0.2) obtained by modified glycine nitrate procedure

“…The endothermic DTA peak observed around 478 1C and 514 1C can be attributed to the chemical change from MnO 2 to Mn 2 O 3 in this structural change [22]. Therefore, the second decomposition stage, accompanied by a medium exothermic effect, represents the burn up of the remainder carbonaceous residue and interaction due to a double exchange between Mn 3 þ and Mn 4 þ ions [23]. The exothermic peak associated with the anion decomposition reaction was 6757 3 1C, confirming that nitrate breakdown occurred in a melt [24].…”