title: Synthesis, phase composition, Mössbauer and magnetic characterization of iron oxide nanoparticles.
abstract: The present work describes the synthesis of iron oxide nanoparticles by thermal decomposition of Fe-precursors in argon and vacuum environments with control over particle size distribution, phase composition and the resulting magnetic properties. The Rietveld refinement analysis of X-ray diffraction data revealed the crystallinity as well the single-phase of γ-Fe2O3 nanoparticles prepared under vacuum, whereas the argon environment leads to the formation of multi-phase composition of γ-Fe2O3/Fe3O4 (90%) and wustite (10%). Synchrotron X-ray absorption near edge structure (XANES) indicates that the predominant phase in both samples is γ-Fe2O3, which is subsequently verified from the Mössbauer spectra. DC magnetic measurements indicate behavior typical of a superparamagnetic system validated by Mössbauer analysis. However, further investigation of ac susceptibility by typical Néel-Arrhenius and Vogel Fulcher magnetic models suggests an influence of interparticle interactions on the overall magnetic behavior of the system.
authors.affiliation: Department of Physics, H. P. University, Shimla 171005, HP, India.
authors.lastname: Sarveena
authors.affiliation: Centro Atomico Bariloche (CNEA), Instituto Balseiro (U. N. Cuyo) and Conicet, 8400 San Carlos de Bariloche, Río Negro, Argentina.
authors.forename: J M
authors.initials: JM
authors.lastname: Vargas
authors.affiliation: UGC DAE Consortium for Scientific Research, Indore 452001, India.
authors.forename: D K
authors.initials: DK
authors.lastname: Shukla
authors.affiliation: Núcleo de Pós-Graduação em Física, Campus Prof. José Aluísio de Campos, UFS, 49100-000 São Cristóvão, SE, Brazil.
authors.forename: C T
authors.initials: CT
authors.lastname: Meneses
authors.affiliation: Instituto de Física de La Plata (IFLP-CONICET), Universidad Nacional de La Plata (UNLP), c.c. 67, 1900 La Plata, Argentina.
authors.forename: P
authors.initials: P
authors.lastname: Mendoza Zélis
authors.affiliation: Department of Physics, H. P. University, Shimla 171005, HP, India.
authors.forename: M
authors.initials: M
authors.lastname: Singh
authors.affiliation: Universidade Federal do Maranhão, Departamento de Física, 65080-805, São Luis, MA, Brazil. surender76@gmail.com and Department of Physics, H. P. University, Shimla 171005, HP, India.
authors.forename: S K
authors.initials: SK
authors.lastname: Sharma