Magnetic packing of graphite encapsulated nickel nanoparticles

Teng, Mao‐Hua; Tsai, Shao-Wei; Chiou, Wen‐An

doi:10.1016/j.jallcom.2009.10.171

Cited by 6 publications

(2 citation statements)

References 8 publications

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“…Ni nanoparticles encapsulated in a carbon matrix, Ni@C nanocomposites, were investigated in Refs. [20][21][22][23][24][25][26][27][28]. Depending on used synthetic techniques, Ni@C nanocomposites can have different carbon structures, morphology and magnetic characteristics.…”

Section: Introductionmentioning

confidence: 99%

Structure and size dependence of the magnetic properties of Ni@C nanocomposites

Manukyan

Elsukova

Mirzakhanyan

et al. 2018

Journal of Magnetism and Magnetic Materials

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Carbon-coated nickel (Ni) nanoparticles, Ni@C nanocomposites, have been synthesized using solid-state pyrolysis of nickel phthalocyanine and metal-free phthalocyanine (NiPc) x •(H 2 Pc) 1-x solid solutions, 0 ≤ x ≤ 1. The Ni concentrations in carbon matrix (c Ni ) of the prepared samples continuously varied in the range of 0-3at.% (0-12wt.%). The average nanoparticle size varied within 4-40 nm range. All samples containing single domain Ni nanoparticles exhibit both ferromagnetic and superparamagnetic properties because of the wide range of size distribution. An abrupt drop of saturation magnetization has been observed with decrease in size of Ni nanoparticles from 40 nm to 12 nm. Nearly linear dependence of saturation magnetization on the nanoparticle surface/volume ratio can be interpreted as a result of contact interaction between Ni nanoparticles and the carbon matrix which provides an electron transfer from carbon matrix to nickel. However, further reductions in nanoparticle size increase magnetization growth of which can apparently contribute to the emergence of the giant paramagnetism due to large orbital moments of conductive electrons. The size effects and surface magnetic anisotropy in Ni@C nanocomposites are revealed in the measurements of coercive field, zero-field cooling (ZFC) susceptibility, blocking temperatures and ferromagnetic resonance spectra. Concentration dependencies of ferromagnetic and electron paramagnetic resonance parameters in Ni@C nanocomposites have also been investigated and their peculiarities highlighted. A correlation between concentration dependencies of FMR and SQUID magnetometry parameters, namely between the g-factor curvesg e f f , the resonance linewidth -∆H FMR and coercive field -H c , have been observed.

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Section: Introductionmentioning

confidence: 99%

Structure and size dependence of the magnetic properties of Ni@C nanocomposites

Manukyan

Elsukova

Mirzakhanyan

et al. 2018

Journal of Magnetism and Magnetic Materials

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“…The nanoparticles of Ni encapsulated in carbon matrix, the Ni@C nanocomposites, were studied in [16][17][18][19][20][21][22][23][24]. Despite a considerable number of works, the systematic study of magnetic properties of nickel nanoparticles depending on the size and concentration of the metal is absent.…”

Section: Introductionmentioning

confidence: 99%

FMR and EPR in Ni@C nanocomposites: Size and concentration effects

et al. 2017

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Ni@C nanoparticles encapsulated in carbon coating have been investigated depending on the size and concentration of Ni in carbon. The nanoparticles of nickel were prepared with the average diameters changing in a broad range of 4-45 nm, and the concentration of Ni in C varies in 2-12 wt%. To prepare the Ni@C nanocomposites the solid solutions of nickel phthalocyanine-metal-free phthalocyanine (NiPc) x (H 2 Pc) 1-x , 0 ≤ x ≤ 1 were synthesized and the solidphase pyrolysis of these compounds was performed. In the case of ultradispersive Ni nanoparticles (the interval of quantum dots is 1-10 nm), a considerable shift of the resonance field and broadening of resonance absorption field were revealed in the spectra of FMR at room temperature. The data were interpreted taking into account the essential contribution of the surface magnetic anisotropy, the magnetic field of which far exceeds the magnetic field of volume anisotropy.

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Nanoparticle‐Based Material Shaping

2012

Nanoparticulate Materials

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Magnetic packing of graphite encapsulated nickel nanoparticles

Cited by 6 publications

References 8 publications

Structure and size dependence of the magnetic properties of Ni@C nanocomposites

Structure and size dependence of the magnetic properties of Ni@C nanocomposites

FMR and EPR in Ni@C nanocomposites: Size and concentration effects

Nanoparticle‐Based Material Shaping

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