Title
Magnetic and structural properties of ferrihydrite/hematite nanocomposites
Date Issued
15 May 2016
Access level
metadata only access
Resource Type
journal article
Author(s)
Camacho-Aguilar K.
Ramos-González R.
Martinez A.
Herrera-Trejo M.
Baggio-Saitovitch E.
Instituto Politécnico Nacional
Publisher(s)
Elsevier
Abstract
A rich variety of ferrihydrite/hematite nanocomposites (NCs) with specific size, composition and properties were obtained in transformation reactions of 2-line ferrihydrite. Transmission electron microscopy (TEM) observations showed that the NCs consist of clusters of strongly aggregated nanoparticles (NPs) similarly to a "plum pudding", where hematite NPs "raisins" are surrounded by ferrihydrite "pudding". Magnetic measurements of the NCs correlate very well with TEM results; i.e., higher coercive fields correspond to greater hematite crystallite size. First order reversal curve (FORC) measurements were used for the characterization of the magnetic components of the NCs. FORC diagrams revealed that the NCs prepared at short times are composed by single domains with low coercivity, and NCs prepared at times larger than 60 min exhibited elongated distribution along the Hc axis. It suggested that these samples consist of mixtures of different kinds of hematite particles, ones with low coercivity and others with coercivity greater than 600 Oe. For NCs prepared at times larger than 60 min, Mossbauer spectroscopy revealed the presence of two sextets, which one was assigned to fine hematite particles and other to hematite particles with hyperfine parameters near to bulk hematite. The correlation of the structural and magnetic properties of the ferrihydrite/hematite NCs revealed important characteristics of these materials which have not been reported elsewhere.
Start page
221
End page
227
Volume
406
Language
English
OCDE Knowledge area
Ingeniería de materiales
Nano-materiales
Subjects
Scopus EID
2-s2.0-84957565008
Source
Journal of Magnetism and Magnetic Materials
ISSN of the container
03048853
Sources of information:
Directorio de Producción Científica
Scopus