Superparamagnetic nanosized perovskite oxide La0.5Sr0.5Ti0.5Fe0.5O3 synthesized by modified polymeric precursor method: effect of calcination temperature on structural and magnetic properties
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The present investigation reports the synthesis of superparamagnetic La0.5Sr0.5Ti0.5Fe0.5O3 by modified polymeric precursor method and the effect of temperature on its structural and magnetic properties. The structures of the phases, calcined at different temperatures, were refined in the space group Pbnm with orthorhombic setting. The crystallite size and specific surface area during the decomposition process were monitored up to 1100 °C. A pure nanosized La0.5Sr0.5Ti0.5Fe0.5O3 powder with high-specific surface area of 49 m2 g-1 was obtained after calcination at 500 °C, while the crystallite size was found to be 18 nm, which was in good agreement with the grain size (19 nm) obtained from TEM investigations. The field dependence of magnetization (M–H) measurements indicate that all the samples exhibit weak ferromagnetic behavior due to slight canting of the adjacent Fe3+ spins. The value Mr/Ms of nano sample calcined at 500 °C indicates the formation of superparamagnetic phase. Magnetization increase significantly with decreasing particle size, while there is sharp decrease in coercivity.
KeywordsPolymeric precursor Rietveld refinements TEM Magnetic properties
We are thankful to Department of Science and Technology, New Delhi for financial support under INSPIRE Program vide letter No. DST/INSPIRE Fellowship/2012/776 (IF120846). We are also thankful to Dr. Harpreet Singh, Central Research Facility Section, Indian Institute of Technology Ropar, for recording XRD. We also thank Prof. Ramesh Chandra, Institute Instrumentation Center, Indian Institute of Technology, Roorkee, for recording EDX, SEM, and TEM. We are also thankful to Director, Central Instruments Facility, Indian Institute of Technology, Guwahati, for carrying out M–H magnetic measurements.
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Conflict of interest
The authors declare that they have no conflict of interest.
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