MgFe2O4 pigment obtained at low temperature

Candeia, Roberlucia Araújo; Souza, Miguel Ângelo Fonseca de; Bernardi, Maria Inês Basso; Maestrelli, Sylma Carvalho; Santos, I. M. G.; Souza, A. G.; Longo, Elson

doi:10.1016/j.materresbull.2005.07.019

Cited by 68 publications

(25 citation statements)

References 19 publications

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“…These nanosized magnetic particles exhibit very interesting properties that made of them promising candidates to be used in different applications such as high density recording, ferrofluids, high frecuency devices, magnetic refrigerators and new pigments (4,5). Concerning the properties of these magnetic particles, namely coercivity, magnetic saturation, remanence and loss, change dramatically as the size of the particles move down into the nanometric range (6,7).…”

Section: Introductionmentioning

confidence: 99%

Nanopartículas de ferrita MFe2O4 (M = Ni y Zn): síntesis hidrotermal y propiedades magnéticas

Puche¹,

Fernández²,

Gutierrez³

et al. 2008

Bol. Soc. Esp. Ceram. Vidr.

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MFe 2 O 4 (M = Ni and Zn) nanoparticles were prepared by the hydrothermal method. The obtained samples were characterized by X-ray and electron diffraction, Scanning and Transmission Electron Microscopy and Mössbauer spectroscopy. The transmission images show homogeneous shape and particle size ranging from 10 to 40 nm, depending on the nature of the M cation. Mössbauer spectroscopy yields to a ratio of occupancy between the A and B sites of 0.7 in the case of NiFe 2 O 4 oxide. DC magnetization (2-300 K) measurements reveal a superparamagnetic behaviour for the ZnFe 2 O 4 sample with a blocking temperature of 20 K. By contrast, in the case of the NiFe 2 O 4 ferrite the blocking temperature appears to be above 300 K and at lower temperature, it shows a ferrimagnetic behaviour arising from the superexchange interactions that take place in this inverse spinel. Mössbauer spectroscopy results confirm the bulk magnetic measurements.Keywords: ferrites, nanoparticles, superparamagnetism, ferrimagnetism, inverse spinel. Nanopartículas de ferrita MFe 2 O 4 (M = Ni y Zn): síntesis hidrotermal y propiedades magnéticas.Se han preparado mediante el método hidrotermal nanopartículas de ferritas MFe 2 O 4 (M = Ni, Zn). Las muestras obtenidas fueron caracterizadas mediante difracción de rayos X y electrones, microscopía electrónica de transmisión y barrido y espectroscopia Mössbauer. Las imágenes de transmisión muestran partículas de forma y tamaño homogéneo de 10 a 40 nm según la naturaleza del catión M. La espectroscopia Mössbauer revela una relación de ocupación entre los sitios A y B por los átomos de hierro de 0.7 en el caso del óxido NiFe 2 O 4 . Las medidas de magnetización DC (2 -300 K) muestran un comportamiento superparamagnético para la muestra ZnFe 2 O 4 con una temperatura de bloqueo de 20 K. En el caso de las nanopartículas de NiFe 2 O 4 la temperatura de bloqueo parece estar por encima de los 300 K mostrando por debajo de la misma, comportamiento ferrimagnético provocado por las interacciones de superintercambio que tienen lugar en esta espinela inversa. Los resultados de espectroscopia Mössbauer confirman los datos de las medidas magnéticas.Palabras clave: ferritas, nanopartículas, superparamgnetismo, ferrimagnetismo, espinela inversa.

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Section: Introductionmentioning

confidence: 99%

Nanopartículas de ferrita MFe2O4 (M = Ni y Zn): síntesis hidrotermal y propiedades magnéticas

Puche¹,

Fernández²,

Gutierrez³

et al. 2008

Bol. Soc. Esp. Ceram. Vidr.

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“…Other re-0932-0776 / 08 / 0900-1052 $ 06.00 c 2008 Verlag der Zeitschrift für Naturforschung, Tübingen · http://znaturforsch.com searchers performed the synthesis of MgFe 2 O 4 by a microwave hydrothermal [6] or sol-gel method [7]. Furthermore, MgFe 2 O 4 has been prepared by the polymeric-precursor method [8] that is based on the formation of a polymeric resin, followed by heat treatment at 1073 K.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Mechanical Activation on the Synthesis of MgFe₂O₄ from Mixtures of MgCO₃· Mg(OH)₂ · xH₂O and FeC₂O₄ ·2H₂O

Berbenni

Marini

Milanese

et al. 2008

Zeitschrift Für Naturforschung B

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The synthesis of MgFe 2 O 4 has been attempted starting from mixtures of 4MgCO 3 · Mg(OH) 2 · xH 2 O and FeC 2 O 4 · 2H 2 O by combining mechanical activtion of the mixtures (by high-energy milling) with annealing at temperatures between 673 and 1073 K. TG measurements of mixtures of the precursors have been performed to assess the reaction mechanism, and to determine the minimum temperature where the two binary oxides (MgO and Fe 2 O 3 ) are formed. X-Ray powder patterns of the milled / annealed mixtures have shown that MgFe 2 O 4 is formed in an amorphous state already upon thermal treatment at 673 K, while annealing of the mixtures (not mechanically activated) at temperatures as high as 1473 K of the mixtures does not lead to the complete formation of MgFe 2 O 4 . The molar specific heat and the Curie temperature of the milled / annealed mixtures have been determined by DSC: MgFe 2 O 4 is obtained provided that the annealing of the milled mixture is performed at temperatures as low as 873 K. The effect of the annealing temperature on the surface area of MgFe 2 O 4 has been determined by BET measurements.

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“…Candeia et al (2006), utilizaram o método solgel para sintetizar magnesioferrita que consiste, basicamente, na utilização de nitrato de ferro (III) e carbonato de magnésio além de ácido cítrico e etileno-glicol, para promover a esterificação, sendo que o final da reação é a formação de um gel polimérico. Holec et al (2009) de magnesioferrita pode ser efetuada pelo método hidrotérmico em microondas, com aquecimento a 150ºC e pressão de 50psi por 25 minutos, em frascos de teflon.…”

Section: Fonte: Costa E Bigham (2009)unclassified

Síntese de magnesioferrita a partir de magnetitas magnesianas

Anami

Costa

2013

Semina: Tech. Ex.

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ResumoMagnesioferrita é um importante mineral devido a sua utilização em diferentes campos da ciência e pelo fato de que no solo, pela ação do intemperismo, pode ser fonte de nutrientes essenciais ao desenvolvimento das plantas. A sua utilização na forma pura ou associada a outros minerais só é possível através da síntese em laboratório. Este trabalho teve por objetivo sintetizar magnesioferrita e hematita a partir de magnetita-magnesiana pelo método de co-precipitação. A metodologia utilizada é uma adaptação do método de síntese de magnetita pura, substituindo parcialmente os sais solúveis de ferro por sais solúveis de magnésio na proporção de 30,0 mol% de Fe por Mg. Para caracterização dos materiais foram utilizadas as técnicas de difração de raios-x, análise química total e susceptibilidade magnética por unidade de massa. Os resultados mostraram que além de magnetita-magnesiana foi sintetizada uma inédita muskoxita, que após o tratamento térmico foi convertida a magnesioferrita e hematita na proporção de 93,1% e 6,9% respectivamente. A substituição isomórfica do Fe por Mg aumentou a estabilidade térmica do mineral ferrimagnético sintetizado. Palavras-chave: Óxidos de ferro. Ferrimagnetismo. Susceptibilidade magnética. Maghemita. AbstractMagnesioferrite is an important mineral due to its use in different scientific fields and by the fact that the soil through the action of weathering, can be a source of nutrients essential for plant development by the fact that in the soil. Its use in pure form or associated with other minerals is only possible through the synthesis in laboratory conditions. This study aimed to synthesize magnesioferrite and hematite from magnesian-magnetite by a co-precipitation procedure. The methodology used is an adaptation of the method of synthesis of pure magnetite, partially replacing the soluble salts of iron with soluble magnesium salts in the proportion of 30.0 mol% of Fe for Mg. The characterization of the synthetic minerals used x-rays diffraction, total chemical analysis and mass specific magnetic susceptibility. The results showed that besides the magnesian-magnetite an unprecedented muskoxita was synthesized, which upon annealing was converted to magnesioferrite and hematite and in the proportion of 93.1% and 6.9% respectively. The isomorphous substitution of Fe for Mg enhanced the thermal stability of the ferrimagnetic mineral synthesized.

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MgFe2O4 pigment obtained at low temperature

Cited by 68 publications

References 19 publications

Nanopartículas de ferrita MFe<sub>2</sub>O<sub>4</sub> (M = Ni y Zn): síntesis hidrotermal y propiedades magnéticas

Nanopartículas de ferrita MFe<sub>2</sub>O<sub>4</sub> (M = Ni y Zn): síntesis hidrotermal y propiedades magnéticas

The Effect of Mechanical Activation on the Synthesis of MgFe₂O₄ from Mixtures of MgCO₃· Mg(OH)₂ · xH₂O and FeC₂O₄ ·2H₂O

Síntese de magnesioferrita a partir de magnetitas magnesianas

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MgFe2O4 pigment obtained at low temperature

Cited by 68 publications

References 19 publications

Nanopartículas de ferrita MFe<sub>2</sub>O<sub>4</sub> (M = Ni y Zn): síntesis hidrotermal y propiedades magnéticas

Nanopartículas de ferrita MFe<sub>2</sub>O<sub>4</sub> (M = Ni y Zn): síntesis hidrotermal y propiedades magnéticas

The Effect of Mechanical Activation on the Synthesis of MgFe2O4 from Mixtures of MgCO3· Mg(OH)2 · xH2O and FeC2O4 ·2H2O

Síntese de magnesioferrita a partir de magnetitas magnesianas

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The Effect of Mechanical Activation on the Synthesis of MgFe₂O₄ from Mixtures of MgCO₃· Mg(OH)₂ · xH₂O and FeC₂O₄ ·2H₂O