Preparation and magnetic study of the CoFe2O4-CoFe2 nanocomposite powders

Ferri-ferromagnetic nanocomposites CoFe 2 O 4 -CoFe 2 were prepared via reduction of the cobalt ferrite CoFe 2 O 4 into a hydrogen atmosphere and by heat treatments. This preparation method yielded powders with relative volume fraction of CoFe 2 O 4 and CoFe 2 in the range 0-0.91. The structure and...

ver descrição completa

Na minha lista:
Detalhes bibliográficos
Principais autores: Araújo, José Humberto de, Machado, Fernando Luis de Araujo, Cabral, Francisco de Assis Olímpio, Soares, João Maria, Rodrigues, Alexandre Ricalde, Araujo, Armando
Formato: article
Idioma:English
Publicado em: Institute of Electrical and Electronics Engineers
Assuntos:
Cobalt ferrites
Exchange coupling
Nanocomposite
Material
Endereço do item:https://repositorio.ufrn.br/jspui/handle/123456789/29204
Tags: Adicionar Tag
Sem tags, seja o primeiro a adicionar uma tag!
id ri-123456789-29204
record_format dspace
spelling ri-123456789-292042020-06-14T07:38:04Z Preparation and magnetic study of the CoFe2O4-CoFe2 nanocomposite powders Araújo, José Humberto de Machado, Fernando Luis de Araujo Cabral, Francisco de Assis Olímpio Soares, João Maria Rodrigues, Alexandre Ricalde Araujo, Armando Cobalt ferrites Exchange coupling Nanocomposite Material Ferri-ferromagnetic nanocomposites CoFe 2 O 4 -CoFe 2 were prepared via reduction of the cobalt ferrite CoFe 2 O 4 into a hydrogen atmosphere and by heat treatments. This preparation method yielded powders with relative volume fraction of CoFe 2 O 4 and CoFe 2 in the range 0-0.91. The structure and the room temperature magnetization of the samples were analyzed by X-ray diffraction, scanning electron microscope (SEM) and transmission electron microscope (TEM), and by vibrating sample magnetometry, respectively. It was found that the saturation magnetization of the nanocomposite powders increases with the volume fraction of the ferromagnetic phase while their coercivity decreases. The highest value (5 kJ/m 3 ) for the maximum energy product (BH) max was obtained for the sample containing 91% in volume of CoFe 2 . This (BH) max is 19% higher than the value measured in pure CoFe 2 O 4 . The magnetic field dependence of the magnetization did also behave as the nanocomposite powders were single-phase materials. This result indicates that the hard ferrimagnet CoFe 2 O 4 and the soft ferromagnet CoFe 2 are effectively exchange coupled and that their magnetization reverses cooperatively in the range of compositions investigated 2020-06-09T18:55:18Z 2020-06-09T18:55:18Z 2008-12-16 article CABRAL, F. A. O.; MACHADO, F. L. A.; ARAÚJO, José Humberto de; SOARES, J. M.; Ricalde, A.; ARAÚJO, A.. Preparation and magnetic study of the CoFe2O4-CoFe2 nanocomposite powders. IEEE Transactions on Magnetics, v. 44, p. 4235-4238, 2008. Disponível em: https://ieeexplore.ieee.org/document/4717406 Acesso em: 09 jun 2020. http://10.1109/TMAG.2008.2001545. 0018-9464 https://repositorio.ufrn.br/jspui/handle/123456789/29204 10.1109/TMAG.2008.2001545 en Attribution 3.0 Brazil http://creativecommons.org/licenses/by/3.0/br/ application/pdf Institute of Electrical and Electronics Engineers
institution Repositório Institucional
collection RI - UFRN
language English
topic Cobalt ferrites
Exchange coupling
Nanocomposite
Material
spellingShingle Cobalt ferrites
Exchange coupling
Nanocomposite
Material
Araújo, José Humberto de
Machado, Fernando Luis de Araujo
Cabral, Francisco de Assis Olímpio
Soares, João Maria
Rodrigues, Alexandre Ricalde
Araujo, Armando
Preparation and magnetic study of the CoFe2O4-CoFe2 nanocomposite powders
description Ferri-ferromagnetic nanocomposites CoFe 2 O 4 -CoFe 2 were prepared via reduction of the cobalt ferrite CoFe 2 O 4 into a hydrogen atmosphere and by heat treatments. This preparation method yielded powders with relative volume fraction of CoFe 2 O 4 and CoFe 2 in the range 0-0.91. The structure and the room temperature magnetization of the samples were analyzed by X-ray diffraction, scanning electron microscope (SEM) and transmission electron microscope (TEM), and by vibrating sample magnetometry, respectively. It was found that the saturation magnetization of the nanocomposite powders increases with the volume fraction of the ferromagnetic phase while their coercivity decreases. The highest value (5 kJ/m 3 ) for the maximum energy product (BH) max was obtained for the sample containing 91% in volume of CoFe 2 . This (BH) max is 19% higher than the value measured in pure CoFe 2 O 4 . The magnetic field dependence of the magnetization did also behave as the nanocomposite powders were single-phase materials. This result indicates that the hard ferrimagnet CoFe 2 O 4 and the soft ferromagnet CoFe 2 are effectively exchange coupled and that their magnetization reverses cooperatively in the range of compositions investigated
format article
author Araújo, José Humberto de
Machado, Fernando Luis de Araujo
Cabral, Francisco de Assis Olímpio
Soares, João Maria
Rodrigues, Alexandre Ricalde
Araujo, Armando
author_facet Araújo, José Humberto de
Machado, Fernando Luis de Araujo
Cabral, Francisco de Assis Olímpio
Soares, João Maria
Rodrigues, Alexandre Ricalde
Araujo, Armando
author_sort Araújo, José Humberto de
title Preparation and magnetic study of the CoFe2O4-CoFe2 nanocomposite powders
title_short Preparation and magnetic study of the CoFe2O4-CoFe2 nanocomposite powders
title_full Preparation and magnetic study of the CoFe2O4-CoFe2 nanocomposite powders
title_fullStr Preparation and magnetic study of the CoFe2O4-CoFe2 nanocomposite powders
title_full_unstemmed Preparation and magnetic study of the CoFe2O4-CoFe2 nanocomposite powders
title_sort preparation and magnetic study of the cofe2o4-cofe2 nanocomposite powders
publisher Institute of Electrical and Electronics Engineers
publishDate 2020
url https://repositorio.ufrn.br/jspui/handle/123456789/29204
work_keys_str_mv AT araujojosehumbertode preparationandmagneticstudyofthecofe2o4cofe2nanocompositepowders
AT machadofernandoluisdearaujo preparationandmagneticstudyofthecofe2o4cofe2nanocompositepowders
AT cabralfranciscodeassisolimpio preparationandmagneticstudyofthecofe2o4cofe2nanocompositepowders
AT soaresjoaomaria preparationandmagneticstudyofthecofe2o4cofe2nanocompositepowders
AT rodriguesalexandrericalde preparationandmagneticstudyofthecofe2o4cofe2nanocompositepowders
AT araujoarmando preparationandmagneticstudyofthecofe2o4cofe2nanocompositepowders
_version_ 1773959191951572992

Registros relacionados