INVESTIGADORES
BERCOFF Paula Gabriela
artículos
Título:
Coercivity enhancement of hexagonal ferrites
Autor/es:
S. E. JACOBO; P. G. BERCOFF
Revista:
Solid State Phenomena
Editorial:
Trans Tech Publications
Referencias:
Año: 2013 vol. 202 p. 113 - 125
ISSN:
1662-9779
Resumen:
Hexagonal
ferrites have been widely used as permanent magnets since their discovery in
the 1950s. In spite of their relatively modest magnetic properties, ferrite
magnets still show the best performance to cost ratio and big efforts are being
made in improving their magnetic capabilities by using different synthesis
methods and compositions.
Different
scientific investigations and techniques (Mössbauer spectrometry, X-ray
diffraction, magnetic measurements) have allowed to optimize the permanent
magnet properties of rare earth substituted hexagonal ferrite magnets such as
La-Co and Nd-Co Sr and Ba ferrites.
However, the solubility of rare earth ions in M-type hexaferrite is very low
and their introduction leads to the formation of secondary phases, which must
be avoided in order to obtain permanent magnets with optimal properties.
We report results
on enhanced coercivity of hexagonal ferrites with Nd-Co substitution. The
synthesis of this kind of ferrite is performed with a defficient,
non-stoichiometric iron content (ratio Fe/ Sr1xRx of 11 instead of
12) in order to diminish secondary phases. Comparison with samples of the same
composition and stoichiometric formulation is made. A further improvement of both intrinsic and
magnetic properties of the Nd-Co substituted ferrite can be obtained by
adjusting the chemical composition.