Effect of Surfactant on Magnetic and Optical Properties of α -Fe2O3 Nanoparticles
I.M. Mirza, A.K. Sarfraz and S.K. Hasanain
Department of Physics, Quaid-i-Azam University, Islamabad, Pakistan
Received: January 26, 2014; In final form: November 6, 2014
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Hematite (α-Fe2O3) nanoparticles and hematite nanoparticles coated with polyvinylpyrrolidone (PVP) are synthesized chemically by co-precipitation. Prolysis and microemulsion methods respectively. An average size of nanoparticles (both coated and uncoated) was found by the broadening of the X-ray diffraction peaks using Scherrer's formula. It was found that coating reduced particle sizes. The attachment of the polymer on the surface of particles was confirmed by the Fourier transform infrared spectroscopy and thermogravimetric analysis. Optical ultraviolet/visible reflectance test also indicated the presence of PVP in coated nanohematites. In magnetic studies, it was observed that coating does not change main magnetic character of the α-Fe2O3 nanoparticles however it reduces DC magnetization (as a function of applied field and temperature) to a considerable amount. Moreover it was observed that after coating Morin transition temperature TM and its width Δ TM shifts to lower values, which is another indication of size reduction.

DOI: 10.12693/APhysPolA.126.1280
PACS numbers: 78.66.Qn, 75.47.Lx, 78.67.Bf, 75.75.-c, 78.67.-n