Crystallite size induced crossover from paramagnetism to superparamagnetism in zinc ferrite nanoparticles. (October 2015)

• Record Type: Journal Article
• Authors: Singh, Jitendra Pal; Gautam, Sanjeev; Srivastava, R.C.; Asokan, K.; Kanjilal, D.; Chae, Keun Hwa
• Is Part Of: Superlattices and microstructures. Volume 86(2015)
• Page Start: 390
• Page End: 394
• Publication Date: 2015-10
• Subjects: Nanoparticles -- Magnetic materials -- Spectroscopy; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2015.07.062
• Languages: English
• ISSNs: 0749-6036

Abstract

Highlights: Synthesis of paramagnetic and superparamagnetic zinc ferrite. Fe 3+ ions along with the concomitant incomplete crystallization are responsible for superparamagnetic behavior. Increase of Fe–O bonds with crystallization. Abstract: Present work investigates the crossover from paramagnetism to superparamagnetism as a function of crystallite size in zinc ferrite nanoparticles using near edge X-ray absorption spectroscopy. Synthesized paramagnetic and superparamagnetic nanoparticles exhibit presence of Fe 2+ and Fe 3+ ions with dominant concentration of Fe 3+ ions. Fe L - and O K -edges spectra of paramagnetic nanoparticles consist of more intense spectral features compared to that of superparamagnetic nanoparticles. This reflects enhanced t 2 g and eg symmetry states of Fe–O hybridized states in paramagnetic nanoparticles induced by increased degree of crystallization.