Rapid synthesis of room temperature ferromagnetic Ag-doped LaMnO{sub 3} perovskite phases by the solution combustion method

• Published in: Materials research bulletin Vol. 45; no. 11
• Main Authors: Bellakki, Manjunath B., Shivakumara, C., Vasanthacharya, N.Y., Prakash, A.S.
• Format: Journal Article
• Language: English
• Published: United States 15-11-2010
• Subjects: ABSORPTION; BOND ANGLE; COMBUSTION; DOPED MATERIALS; ELECTRIC CONDUCTIVITY; FOURIER TRANSFORMATION; LANTHANUM COMPOUNDS; MAGNETIC MOMENTS; MAGNETIC PROPERTIES; MANGANATES; MATERIALS SCIENCE; ORTHORHOMBIC LATTICES; PEROVSKITE; POWDERS; SYNTHESIS; TRIGONAL LATTICES; X-RAY DIFFRACTION
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/J.MATERRESBULL.2010.06.063

We report the rapid solution combustion synthesis and characterization of Ag-substituted LaMnO{sub 3} phases at relatively low temperature using oxalyl dihydrazide, as fuel. Structural parameters were refined by the Rietveld method using powder X-ray diffraction data. While the parent LaMnO{sub 3} crystallizes in the orthorhombic structure, the Ag-substituted compounds crystallize in the rhombohedral symmetry. On increasing Ag-content, unit cell volume and Mn-O-Mn bond angle decreases. The Fourier transform infra red spectrum shows two absorption bands corresponding to Mn-O stretching vibration ({nu}{sub s} mode) and Mn-O-Mn deformation vibration ({nu}{sub b} mode) around 600 cm{sup -1} and 400 cm{sup -1} for the compositions, x = 0.0, 0.05 and 0.10, respectively. Electrical resistivity measurements reveal that composition-controlled metal to insulator transition, with the maximum metal to insulator being 280 K for the composition La{sub 0.75}Ag{sub 0.25}MnO{sub 3}. Increase in magnetic moment was observed with increase in Ag-content. The maximum magnetic moment of 35 emu/g was observed for the composition La{sub 0.80}Ag{sub 0.20}MnO{sub 3}.