Artigo de peri??dico
Size-strain analysis of iron-excess Mn???Zn ferrite nanoparticles using synchrotron diffraction and its correlation with magnetic saturation and isoelectric pH
Registro en:
1533-4880
8
18
10.1166/jnn.2018.15446
aguardando
17.968
Sem Percentil CiteScore
Autor
ICHIKAWA, RODRIGO U.
PARRA, JOAO P.R.L.L.
MARTINS, MURILLO L.
YOSHITO, WALTER K.
SAEKI, MARGARIDA J.
TURRILLAS, XAVIER
MARTINEZ, LUIS G.
Resumen
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. Conselho Nacional de Desenvolvimento Cient??fico e Tecnol??gico (CNPq) Funda????o de Amparo ?? Pesquisa do Estado de S??o Paulo (FAPESP) CNPq: 206983-/2014-0 FAPESP: 10/07639-9