Phase composition and growth mechanisms of half-metal Heusler alloy produced by Pulsed Laser Deposition: From core-shell nanoparticles to amorphous randomic clusters

Checca, N.R.; Caraballo-Vivas, R.J.; Torrão, R.; Rossi, André L.; Reis, M. S.

doi:10.1016/j.matchemphys.2017.04.037

Cited by 21 publications

(5 citation statements)

References 27 publications

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“…Due to the presence of inert gas, when the high-power laser ablates the target surface, the evaporated atoms randomly collide, forming the NPs in the generated plume. They are then collected by the substrate, positioned at 30 mm from the incident surface [5,26]. Transmission Electronic Microscopy (TEM) and High-resolution TEM (HR-TEM) images were obtained for all compositions.…”

Section: Structural Characterizationmentioning

confidence: 99%

“…The sample features can be controlled by the experimental conditions, such as chamber atmosphere, inert gas flux, target to substrate distance, time of deposition, laser wavelength, pulse duration, energy, frequency and fluency [23]. Thus, by changing the deposition conditions, different particles size can be achieved as shown here and already demonstrated for other systems [26], including Gd-Si-Ge compounds produced through ablation in liquids by varying the laser wavelength and pulse duration [18,20]. Besides, different morphologies are being compared when the particle size is considered: i) the ultra-short laser ablation lead to a Gd 5 Si 1.3 Ge 2.7 (x ¼ 0.325) granular thin film, due to the absence of inert gas [16] and ii) the nanosecond laser deposition with Ar atmosphere that resulted in nanoparticles free of substrates.…”

Section: Bulk Compressibility and Intrinsic Surface Pressurementioning

confidence: 99%

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Unit cell volume reduction of Gd5(Si,Ge)4 nanoparticles controlled by bulk compressibility

Andrade

Belo

Checca

et al. 2020

Journal of Alloys and Compounds

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Section: Structural Characterizationmentioning

confidence: 99%

Section: Bulk Compressibility and Intrinsic Surface Pressurementioning

confidence: 99%

Unit cell volume reduction of Gd5(Si,Ge)4 nanoparticles controlled by bulk compressibility

Andrade

Belo

Checca

et al. 2020

Journal of Alloys and Compounds

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“…Such observation is confirmed through the appearance of a bump highlighted at the dM/dT curves 25 . It is worth to point out that the reduction of particle size seems to be affecting only the secondary M-phase since there is no shift on T C for the main O(I) phase, as usually observed in magnetic materials at the micro/nanoscale 11, 35,36 . Such effect can be rising from the higher sensitivity of the M structure over O(I) to applied magnetic field, hydrostatic pressure and particle size 31,37 .…”

Section: B Magnetic Characterizationmentioning

confidence: 79%

Freestanding and flexible composites of magnetocaloric Gd5(Si,Ge)4 microparticles embedded in thermoplastic poly(methyl methacrylate) matrix

et al. 2020

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The implementation of processed magnetic materials onto thermoplastics can be an approach for practical application of brittle intermetallic materials with the advantage of enlarging the range of applications. In the present work, we evaluate the effect of blending magnetocaloric Gd 5 Si 2.4 Ge 1.6 micrometric particles with 3.4 µm in different weight fractions onto a flexible, transparent and non-magnetic poly(methyl methacrylate) (PMMA). A close to homogeneous grain distribution along the polymer surface were achiever by using a simple solvent casting method for evaluation of their magnetocaloric properties. From XRD analysis, it was found a relative unit cell volume reduction of ∼2.5×10 3 ppm for the composite with 70 wt.% of powder as a result of interfacial interactions between the components. Although PMMA does not influence the magnetic nature of microparticles main phase, a reduction on the amount of secondary monoclinic phase occurs for all produced composite samples. As a consequence, a weakening on the effect of secondary phases on the micropowder magnetocaloric response is observed as a result of hydrostatic pressure from the difference between thermal expansions of matrix and filler.

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“…The NPs’ size distribution (PSDs) was calculated from histograms after counting approximately 500 NPs. The PSDs are highly asymmetric and are well represented by log-normal functions [ 40 ]. The obtained parameters are summarized in Table 3 , where 〈 D 〉 is the mean NPs size, D m is the mode, ∆ is the standard deviation, and D s is the dimensionless skewness.…”

Section: Resultsmentioning

confidence: 99%

Raman, TEM, EELS, and Magnetic Studies of a Magnetically Reduced Graphene Oxide Nanohybrid following Exposure to Daphnia magna Biomarkers

et al. 2022

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A ternary nanocomposite made of nanomaghemite, nanoanatase, and graphene oxide has been successfully synthesized using an inorganic coprecipitation approach, and it has been systematically investigated by X-ray diffraction, transmission electron microscopy, and different spectrocopic techniques (electron energy loss, µ-Raman, and 57Fe Mössbauer) after interaction with an effluent containing Daphnia magna individuals. Specifically, the influence of the nanocomposite over the Daphnia magna carapace, administered in two doses (0.5 mg mL−1 and 1 mg mL−1), has been characterized using µ-Raman spectroscopy before and after laser burning protocols, producing information about the physicochemical interaction with the biomarker. The thermal stability of the nanocomposite was found to be equal to 500 °C, where the nanoanatase and the nanomaghemite phases have respectively conserved their structural identities. The magnetic properties of the nanomaghemite have also been kept unchanged even after the high-temperature experiments and exposure to Daphnia magna. In particular, the size, texture, and structural and morphological properties of the ternary nanocomposite have not shown any significant physicochemical modifications after magnetic decantation recuperation. A significant result is that the graphene oxide reduction was kept even after the ecotoxicological assays. These sets of observations are based on the fact that while the UV-Vis spectrum has confirmed the graphene oxide reduction with a localized peak at 260 nm, the 300-K and 15-K 57Fe Mössbauer spectra have only revealed the presence of stoichiometric maghemite, i.e., the two well-defined static magnetic sextets often found in the bulk ferrimagnetic counterpart phase. The Mössbauer results have also agreed with the trivalent-like valence state of Fe ions, as also suggested by electron energy loss spectroscopy data. Thus, the ternary nanocomposite does not substantially affect the Daphnia magna, and it can be easily recovered using an ordinary magnetic decantation protocol due to the ferrimagnetic-like character of the nanomaghemite phase. Consequently, it shows remarkable physicochemical properties for further reuse, such as cleaning by polluted effluents, at least where Daphnia magna species are present.

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Phase composition and growth mechanisms of half-metal Heusler alloy produced by Pulsed Laser Deposition: From core-shell nanoparticles to amorphous randomic clusters

Cited by 21 publications

References 27 publications

Unit cell volume reduction of Gd5(Si,Ge)4 nanoparticles controlled by bulk compressibility

Unit cell volume reduction of Gd5(Si,Ge)4 nanoparticles controlled by bulk compressibility

Freestanding and flexible composites of magnetocaloric Gd5(Si,Ge)4 microparticles embedded in thermoplastic poly(methyl methacrylate) matrix

Raman, TEM, EELS, and Magnetic Studies of a Magnetically Reduced Graphene Oxide Nanohybrid following Exposure to Daphnia magna Biomarkers

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