Microwave Absorption in Nanostructured Spinel Ferrites

Vázquez‐Victorio, Genaro; Acevedo-Salas, Ulises; Valenzuela, R.

doi:10.5772/56058

Cited by 12 publications

(9 citation statements)

References 58 publications

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“…2a (bottom plot 5, central part), there is a step-like feature in the central part of the differential spectra of NiFe 2 O 4 . Similar feature was previously observed in FMR (ferromagnetic resonance) spectra of Fe 3 O 4 and was then shown to be a result of the microparticle concentration dependence of the microwave signal [9]. In particular, the concentration increase above 0.1% led to a disappearance of this structure due to an increase in interparticle interaction and clusterization effect.…”

Section: Contributedsupporting

confidence: 67%

EPR and SPM studies of Zn‐Ni ferrites

Aliyeva

Nadjafov

et al. 2015

Phys. Status Solidi C

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Electron paramagnetic resonance studies have been carried out over 3.7‐300 K on micropowders of Ni1‐xZnxFe2O4 ferrites, obtained by high temperature synthesis and preliminary characterized by X‐ray diffraction and differential scanning calorimetry in a wide range of tempera‐tures. Complimentary, scanning probe microscopy, compris‐ing atomic and magnetic force microscopies has been applied to polycrystalline Ni1‐xZnxFe2O4thin films. The correlation between X‐ray and differential scanning calorimetry data has been observed. Deconvolution of the obtained paramagnetic resonance spectra into Gaussian components and their further analysis have allowed retrival of the compensation points of the magnetc momenta of the sublattices of Ni1‐xZnxFe2O4, as well as of superparamagnetism effect and g‐factors dispersion verified by studies on polycrystalline thin films. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Contributedsupporting

confidence: 67%

EPR and SPM studies of Zn‐Ni ferrites

Aliyeva

Nadjafov

et al. 2015

Phys. Status Solidi C

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“…At room temperature, the first derivative EPR spectrum (Fig. 10) of the GSH-CoFe 2 O 4 MNPs shows a mixing of two lines consisting of a broad component corresponding to typical anisotropic contributions and a narrow one, which has been attributed to surface isotropic contributions [35]. This is typical for superparamagnetic resonance [35].…”

Section: Resultsmentioning

confidence: 95%

“…The position of resonance of a paramagnet is defined by the g -factor and it was calculated using Eq. (1):g=hυHβwhere h is the Planck's constant, υ is the frequency of the microwave, H is the magnetic field occurring, and β is the Bohr magneton [35].…”

Section: Methodsmentioning

confidence: 99%

Dual phototransformation of the pollutants methyl orange and Cr (VI) using phthalocyanine-cobalt ferrite based magnetic nanocomposites

Mapukata

Osifeko

Nyokong

2019

Heliyon

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Bifunctional nanocomposites based on zinc phthalocyanines and glutathione capped CoFe 2 O 4 magnetic nanoparticles (GSH-CoFe 2 O 4 MNPs) are applied in a binary system wherein simultaneous photooxidation of methyl orange (MO) and photoreduction of Cr (VI) are conducted. The photoactivity of two zinc Pcs with different functional moieties are compared based on their interactions with GSH-CoFe 2 O 4 MNPs. Conjugation of the Pcs to the GSH-CoFe 2 O 4 MNPs not only enhanced their singlet oxygen production but also their photocatalytic activity in both photooxidation and photoreduction experiments. Using electron paramagnetic resonance (EPR) spectroscopy, the Pc-MNP conjugates reported herein were found to exhibit superparamagnetic behaviour, giving the advantage of easy separation using an external magnetic field post application, an attractive attribute for heterogeneous catalysis. The catalysts reported herein are therefore good candidates as catalysts for real life water purification analyses as they facilitate the treatment of both organic and inorganic water pollutants.

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“…It is caused by a reduction in the diameter of the particles, which increases the share of surface atom fraction as compared to the core atoms' fraction. This is illustrated the best by the comparison of nanoparticles ø ≈ 100 nm, for which the surface fraction constitutes 6% of the total amount of atoms with nanoparticles ø ≈ 5 nm, where it already reaches about 78% of all atoms (Schmid and Corain 2003;Vázquez-Victorio et al 2013). The gold-based nanomaterials (AuNPs) are characterised by a controlled size dispersion, stability, higher adsorption properties and good optical properties (Lee et al 2010).…”

Section: Introductionmentioning

confidence: 97%

Metal Nanoparticles – Their Use and Impact on Plants Growing in Laboratory Conditions

BEDNAREK¹,

MGŁOSIEK²,

Kulpa³

2019

Folia Pomer. Univ. Technol. Stetin., Agric., Aliment., Pisc., Z

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There is an increasing interest in nanotechnology all around the world. Nanoparticles differ from the classic material from which they are made in that they change their physical and chemical properties below certain sizes. Thanks to these properties, they are used both in scientific research, medicine and industry, and in recent years also in agriculture. Depending on the type of metal and size of the particules, however, their impact on plant development varies. There are different reports concerning the impact of nanoparticles on the growth and development of plants. In this paper, we gather the knowledge acquired up to now on the interactions of specified nanoparticles -of gold, silver, copper and platinum with plants cultivated in laboratory conditions. The existing research does not allow us to determine unequivocally what impact nanometals have on the plants. The properties that make them unique may have both a negative and positive impact on plants. In a great deal of research, the impact of the nanoparticles on the decrease of the plants' growth and formation of sorter shoots and roots was observed. A high concentration of nanoparticles was also decreasing the chlorophyll content, photosynthesis, transpiration and stomatal conductance rates. The contact of plants with nanoparticles was also manifesting itself by an increased oxidative stress, as a result of which in plant tissues, an over-production of reactive oxygen species damaging lipids of the cell membrane and the DNA was observed. A slower regeneration of plants and their dieback was frequently observed in the case of the addition of nanoparticles to nutrient mediums in the in vitro cultures. By carrying out a series of research with the use of nanoparticles, researchers concluded that their appropriate concentrations may be used in order to improve seed germination, increase growth and plant production as well as their protection and improvement of production of bioactive compounds.

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Microwave Absorption in Nanostructured Spinel Ferrites

Cited by 12 publications

References 58 publications

EPR and SPM studies of Zn‐Ni ferrites

EPR and SPM studies of Zn‐Ni ferrites

Dual phototransformation of the pollutants methyl orange and Cr (VI) using phthalocyanine-cobalt ferrite based magnetic nanocomposites

Metal Nanoparticles – Their Use and Impact on Plants Growing in Laboratory Conditions

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