Size-Strain Analysis of Iron-Excess Mn-Zn Ferrite Nanoparticles Using Synchrotron Diffraction and Its Correlation with Magnetic Saturation and Isoelectric pH

Author(s)

Ichikawa, Rodrigo U. ^[1] ; Parra, Joao P. R. L. L. ^[2] ; Martins, Murillo L. ^[3] ; Yoshito, Walter K. ^[1] ; Saeki, Margarida J. ^[2] ; Turrillas, Xavier ^{[4, 5]} ; Martinez, Luis G. ^[1]

Affiliation

^[1] Inst Pesquisas Energet & Nucl, BR-05508000 Sao Paulo, SP - Brazil

^[2] Univ Estadual Paulista, UNESP, BR-18618970 Botucatu, SP - Brazil

^[3] Univ Copenhagen, Niels Bohr Inst, Blegdamsvej 17, DK-2100 Copenhagen - Denmark

^[4] Inst Ciencia Mat Barcelona, Campus UAB, Bellaterra 08193 - Spain

^[5] ALBA Synchrotron, Carrer Llum 2-26, E-08290 Barcelona - Spain

• Document type: Journal article
• Source: Journal of Nanoscience and Nanotechnology; v. 18, n. 8, p. 5697-5703, AUG 2018.
• Web of Science Citations: 1

Abstract

Iron-excess Mn-Zn ferrite nanoparticles were prepared by coprecipitation with sodium hydroxide (NaOH) at different concentrations (0.1, 0.2, 0.5 and 1.0 mol/L). The results of X-ray diffraction (XRD) analysis using Whole Powder Pattern Modeling (WPPM) showed that higher concentrations of NaOH promote crystallite growth and broader dispersion in crystallite sizes. Energy dispersive X-ray spectroscopy indicates that zinc loss is noticeable when {[}NaOH] = 0.2 mol/L. XRD revealed also a significant less-crystalline phase contribution alongside the main peaks of the nanocrystalline cubic spinel ferrite phase. The less-crystalline fraction is lower for the ferrite obtained with 0.2 mol/L of NaOH, being about 50% and more than 70% for the other samples. Despite of the less-crystalline fraction and the excess of iron, no secondary phases were detected. The Warren curves showed that the concentration of NaOH significantly influences the microstrain in the crystallites, being smaller for the sample obtained with NaOH at 0.2 mol/L. The sample prepared with this condition presented the better properties to be used as magnetic tracer in clinical diagnoses combining small mean crystallite size, low microstrain, which resulted in materials with higher magnetic saturation and high surface charge under blood pH. (AU)

• FAPESP's process: 10/07639-9 - Gastrointestinal motility: clinical investigations, physiopathology and biopharmaceutical
• Grantee: Ricardo Brandt de Oliveira
• Support Opportunities: Research Projects - Thematic Grants