Magnetic granulometry and Mössbauer spectroscopy of Fe m O n –SiO 2 colloidal nanoparticles

Харитонский, П. В.; Kamzin, A. S.; Гареев, К. Г.; Valiullin, A. A.; Везо, О. С.; Sergienko, E. S.; Королев, Д. В.; Kosterov, Andrei; Lebedev, S. V.; Gurylev, A.; Reinyuk, Anton

doi:10.1016/j.jmmm.2018.04.044

Cited by 18 publications

(12 citation statements)

References 22 publications

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“…The presence of sextet with IS of 0.61 is unequivocal evidence of Fe +2 coming from magnetite phase. The third sextet (IS of 0.47 mm s −1 , H eff of 460 kOe) suggests the presence of maghemite (γ‐Fe 2 O 3 ), which commonly occurs in magnetite materials due to the natural oxidation of magnetite when exposed to air . Fe 3+ in tetrahedral site is shared between magnetite and maghemite phases.…”

Section: Resultsmentioning

confidence: 99%

Magnetically Responsive Silica Hollow Spheres: Straightforward Synthesis of Accessible Micro‐Sized Containers

Deon

Andrade

Nicolodi

et al. 2018

Part & Part Syst Charact

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Silica hollow spheres are obtained as micro‐sized containers with magnetic‐field‐induced mobility. The completely empty hollow spheres are proved accessible with features of confined environment, where an unexpected structured fluorescence emission with large Stokes' shift is observed. This multifunctional system is achieved through a controllable etching of magnetite from magnetite@silica core–shell with hydrochloric acid solution, resulting in silica hollow spheres coupled with remaining magnetite@silica. The increase in the etching time leads to an increase in the proportion of hollow to magnetite‐occupied spheres, and the obtained hollow spheres are completely empty. The remaining magnetite particles have their crystalline structure preserved and even the material with higher proportion of hollow spheres presents high saturation magnetization, which grants response from the whole system induced by a magnetic field. The accessibility of the hollow structure is successfully observed by steady‐state fluorescence spectroscopy using toluene as optical probe.

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Section: Resultsmentioning

confidence: 99%

Magnetically Responsive Silica Hollow Spheres: Straightforward Synthesis of Accessible Micro‐Sized Containers

Deon

Andrade

Nicolodi

et al. 2018

Part & Part Syst Charact

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“…The method of magnetic granulometry [168,169], along with other approaches in rock magnetism [88,89,116,165], confirms that the shape and size of bacterial magnetite crystals correspond to a single-domain [170] or pseudo-single-domain [82] (metastable singledomain [167]) state, with the aspect ratio and particle length varying over a wide range, up to one order of magnitude, depending on magnetofossil geography [171], and differs little for cultivated and non-cultivated MTB strains when taking into consideration statistical data [172]. Exceptionally, multi-domain [173] and superparamagnetic [117] magnetite grains originating from magnetofossils have been found in natural conditions.…”

Section: Magnetofossils and Their Propertiesmentioning

confidence: 99%

Magnetotactic Bacteria and Magnetosomes: Basic Properties and Applications

Гареев

Grouzdev²,

Харитонский

et al. 2021

Magnetochemistry

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Magnetotactic bacteria (MTB) belong to several phyla. This class of microorganisms exhibits the ability of magneto-aerotaxis. MTB synthesize biominerals in organelle-like structures called magnetosomes, which contain single-domain crystals of magnetite (Fe3O4) or greigite (Fe3S4) characterized by a high degree of structural and compositional perfection. Magnetosomes from dead MTB could be preserved in sediments (called fossil magnetosomes or magnetofossils). Under certain conditions, magnetofossils are capable of retaining their remanence for millions of years. This accounts for the growing interest in MTB and magnetofossils in paleo- and rock magnetism and in a wider field of biogeoscience. At the same time, high biocompatibility of magnetosomes makes possible their potential use in biomedical applications, including magnetic resonance imaging, hyperthermia, magnetically guided drug delivery, and immunomagnetic analysis. In this review, we attempt to summarize the current state of the art in the field of MTB research and applications.

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“…При 1.8 K приобретается довольно большой магнитный момент, который, однако, спадает почти до нуля по мере приближения к комнатной температуре. Ненулевое, хотя и малое, значение магнитного момента при 300 K можно объяснить эффектом взаимодействия между суперпарамагнитными частицами [9]. Излом на кривой RT-SIRM(T) около 240 K может быть проявлением перехода Морина [10,11] в гематите, некоторое количество которого присутствует в образце согласно данным рентгеновской дифрактометрии.…”

Section: результаты и обсуждениеunclassified

“…Теоретические значения остаточной намагниченности насыщения исследуемых образцов были рассчитаны с помощью модифицированного метода моментов для системы диполь-дипольно-взаимодействующих одноосных частиц, как в работах [9,13].…”

Section: результаты и обсуждениеunclassified

“…Для RT-SIRM: сплошные кривые -охлаждение, пунктирные -нагрев.Для учета двухфазности системы были использованы следующие приближения для намагниченности насыщения и остаточной намагниченности насыщения соответственноM s = c 1 I s 1 + c 2 I s 2 , M rs = c 1 x 1 I s 1 + c 2 x 2 I s 2 , где I s 1 и I s 2 -спонтанные намагниченности, c 1 и c 2 -объемные концентрации, x 1 и x 2 -доли частиц(вносящих вклад в остаточную намагниченность) магнетита/маггемита и титаномагнетита соответственно. Из-за особенностей теоретической модели[6,9,13] здесь и далее намагниченности M s и M rs -магнитный момент единицы объема (volume magnetization).…”

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Магнитные состояния двухфазных синтезированных частиц Fe-=SUB=-m-=/SUB=-O-=SUB=-n-=/SUB=--Fe-=SUB=-3-x-=/SUB=-Ti-=SUB=-x-=/SUB=-O-=SUB=-4-=/SUB=-: экспериментальный и теоретический анализ

Харитонский¹,

Kosterov²,

Гурылёв³

et al. 2020

Физика Твердого Тела

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In this work, the materials of FemOn – Fe3-xTixO4 composition have been obtained using the sol-gel method and hydrothermal treatment. The synthesis conditions favor the formation of composites containing titanomagnetite in a rather low concentration. Based on the hysteresis curves and temperature dependences of the remanent magnetization, theoretical analysis of the composites magnetic properties has been carried out using a model of clustered two-phase particles bound with magnetostatic interaction.

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Magnetic granulometry and Mössbauer spectroscopy of Fe m O n –SiO 2 colloidal nanoparticles

Cited by 18 publications

References 22 publications

Magnetically Responsive Silica Hollow Spheres: Straightforward Synthesis of Accessible Micro‐Sized Containers

Magnetically Responsive Silica Hollow Spheres: Straightforward Synthesis of Accessible Micro‐Sized Containers

Magnetotactic Bacteria and Magnetosomes: Basic Properties and Applications

Магнитные состояния двухфазных синтезированных частиц Fe-=SUB=-m-=/SUB=-O-=SUB=-n-=/SUB=--Fe-=SUB=-3-x-=/SUB=-Ti-=SUB=-x-=/SUB=-O-=SUB=-4-=/SUB=-: экспериментальный и теоретический анализ

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