Spin glass like transition and the exchange bias effect in Co3O4 nanoparticles anchored onto graphene sheets

Sarkar, Samrat; Mondal, A.; Giri, N.; Ray, Rajat

doi:10.1039/c8cp06659k

Cited by 16 publications

(14 citation statements)

References 38 publications

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“…Наблюдается расхождение линий ZFC и FC при температурах T ir r ∼ 70 и 60 K соответственно (таблица). Сходное температурно-зависимое поведение намагниченности было зарегистрировано в нескольких экспериментальных кривых ZFC−FC для наночастиц Co 3 O 4 [17][18][19][20][21][22]30]. Расхождение линий ZFC и FC может быть отнесено к спин-стекловидному поведению некомпенсированных спинов на поверхности нанокристаллов.…”

Section: результаты и обсуждениеunclassified

“…Увеличение намагниченности образца № 3 ниже 10 K является отличительной чертой данного образца от объемного. Наличие низкотемпературного перехода свидетельствует о существовании некомпенсированных поверхностных спинов [38].…”

Section: результаты и обсуждениеunclassified

“…Ионы Co 3+ в октаэдрических позициях являются диамагнитными вследствие расщепления 3d-уровней октаэдрическим кристаллическим полем и полного заполнения уровней t 2g . Исследование наночастиц Co 3 O 4 показало образование метастабильных состояний, таких как суперпарамагнитное и спиновое стекло [17][18][19], связанных с увеличением площади поверхности нанокристаллов. По данным [20], наночастицы Со 3 О 4 , диспергированные в SiO 2 , проявляют супер-парамагнитное поведение с температурой блокировки T B = 3.4 K. В работе [21] обнаружен антиферромагнитный переход при 26 K для частиц размером 17 nm, в то время как для объемных образцов 1−2 µm подобный переход наблюдался при 30 K. Дополнительно авторы [21] зафиксировали слабый ферромагнетизм (FM) ниже температуры Нееля и эффект обменного смещения петли гистерезиса.…”

Section: Introductionunclassified

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Морфология и магнитные свойства полых сфер Co-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-

Дмитриев¹,

Владимирова²,

Есаулков³

et al. 2020

Физика Твердого Тела

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Nanostructured hollow spheres of Co3O4 were synthesized by ultrasonic spray pyrolysis. Nanocrystals forming the structure of spheres differ in size and packing density, depending on the synthesis conditions. The samples were certified by X-ray diffraction, scanning electron microscopy, low-temperature nitrogen sorption, vacuum pycnometry, Raman and XPS spectroscopy. The field and temperature dependences of the magnetization showed that the size and packing density of nanocrystals determine the magnetic characteristics and the Néel temperature of hollow Co3O4 spheres.

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Section: результаты и обсуждениеunclassified

Section: Introductionunclassified

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Морфология и магнитные свойства полых сфер Co-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-

Дмитриев¹,

Владимирова²,

Есаулков³

et al. 2020

Физика Твердого Тела

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“…Confocal Raman microscopy with its high spatial resolution and unique compositional sensitivity is used as a unique label-free tool to trace drugs and nanoparticles within cells. [27][28][29][30][31] The cells and their components are analysed via their vibrational spectra owing to differences in their biochemical compositions. The Raman nanoparticle signature therefore enables precise nanoparticle detection in the cell without any labeling.…”

Section: Introductionmentioning

confidence: 99%

Assessing Cobalt Metal Nanoparticles Uptake by Cancer Cells Using Live Raman Spectroscopy

Rauwel¹,

Al-Arag²,

Salehi³

et al. 2020

IJN

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Nanotechnology applied to cancer treatment is a growing area of research in nanomedicine with magnetic nanoparticle-mediated anti-cancer drug delivery systems offering least possible side effects. To that end, both structural and chemical properties of commercial cobalt metal nanoparticles were studied using label-free confocal Raman spectroscopy. Materials and Methods: Crystal structure and morphology of cobalt nanoparticles were studied by XRD and TEM. Magnetic properties were studied with SQUID and PPMS. Confocal Raman microscopy has high spatial resolution and compositional sensitivity. It, therefore, serves as a label-free tool to trace nanoparticles within cells and investigate the interaction between coating-free cobalt metal nanoparticles and cancer cells. The toxicity of cobalt nanoparticles against human cells was assessed by MTT assay. Results: Superparamagnetic Co metal nanoparticle uptake by MCF7 and HCT116 cancer cells and DPSC mesenchymal stem cells was investigated by confocal Raman microscopy. The Raman nanoparticle signature also allowed accurate detection of the nanoparticle within the cell without labelling. A rapid uptake of the cobalt nanoparticles followed by rapid apoptosis was observed. Their low cytotoxicity, assessed by means of MTT assay against human embryonic kidney (HEK) cells, makes them promising candidates for the development of targeted therapies. Moreover, under a laser irradiation of 20mW with a wavelength of 532nm, it is possible to bring about local heating leading to combustion of the cobalt metal nanoparticles within cells, whereupon opening new routes for cancer phototherapy. Conclusion: Label-free confocal Raman spectroscopy enables accurately localizing the Co metal nanoparticles in cellular environments. The interaction between the surfactant-free cobalt metal nanoparticles and cancer cells was investigated. The facile endocytosis in cancer cells shows that these nanoparticles have potential in engendering their apoptosis. This preliminary study demonstrates the feasibility and relevance of cobalt nanomaterials for applications in nanomedicine such as phototherapy, hyperthermia or stem cell delivery.

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“…Metal oxides such as WO 3 [22], SnO 2 [23], Mn 2 O 3 [24], and Co 3 O 4 [25] have been extensively investigated as selective material for chemical sensors due to their high electrochemical activity. Many metal oxideÀ graphene nanocomposite with different morphologies for specific applications such as MnO 2 À graphene [26,27], Co 3 O 4 À graphene [28,29], SnO 2 À graphene [30,31] and ZnOÀ graphene [32] have been prepared successfully. Arfin et al [33] have been synthesized graphene oxideÀ ZnO nanocomposite, then modified on electrode for the detection of phenol.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Ferrosoferric Oxide‐graphene Oxide Nanocomposite by Isoelectric Point Method for the Detection of Catechol

Wang

Cheng

2019

Electroanalysis

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Ferrosoferric oxide functionalized graphene oxide nanocomposite with layer by layer structure was synthesized by isoelectric point method in this work. The prepared material was characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. Then the material was used to modify a glassy carbon electrode to fabricate an electrochemical sensor for the detection of catechol. The electrochemical sensor exhibited excellent electrochemical performance towards the detection of catechol with a linear response in the range of 5–205 μM and a detection limit of 2.32 μM. Furthermore, the electrochemical sensor showed excellent selectivity, stability and repeatability. These results revealed ferrosoferric oxide functionalized graphene oxide nanocomposite has potential applications in the fabrication of electrochemical sensors.

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Spin glass like transition and the exchange bias effect in Co₃O₄ nanoparticles anchored onto graphene sheets

Cited by 16 publications

References 38 publications

Морфология и магнитные свойства полых сфер Co-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-

Морфология и магнитные свойства полых сфер Co-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-

<p>Assessing Cobalt Metal Nanoparticles Uptake by Cancer Cells Using Live Raman Spectroscopy</p>

Synthesis of Ferrosoferric Oxide‐graphene Oxide Nanocomposite by Isoelectric Point Method for the Detection of Catechol

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