Negative thermal expansion of nanoporous anodic aluminum oxide membranes

Forzani, Luisina; Ramos, C.A.; Brigneti, E. Vassallo; Gennaro, Ana María; Koropecki, R. R.

doi:10.1063/1.5074083

Cited by 7 publications

(5 citation statements)

References 34 publications

(29 reference statements)

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“…In a previous study based on XRD measurements [20], we reported an average negative thermal expansion coefficient < >= −(1.6 ± 1.5) × 10 −6 K −1 along the NW axis for the Ni NW inside AAO, between 110K and 350K. The analysis of this result [20] led us to conclude that the empty AAO matrix also has a negative thermal expansion in this Trange, opposite to the behavior of bulk alumina. Using this result, the experimental deformation of Ni NW in AAO at 120K relative to their equilibrium state at 310 K can be…”

Section: Please Cite This Article As Doi: 101063/15132539mentioning

confidence: 72%

“…In a recent XRD study of Ni NW-AAO membranes in which the aluminum substrate had been removed [20] we found an effective negative thermal expansion of the nanocomposite, leading us to conclude that the freestanding AAO also has a negative thermal expansion coefficient in the direction of the pore axes. In this work, we present the temperature dependence of the magnetic properties of the freestanding nanocomposite Ni NW-AAO, measured using DC magnetometry and ferromagnetic resonance.…”

mentioning

confidence: 67%

“…Bragg reflections, when compared with that of Ni powder spectrum, gives evidence that there is no principal texture, but a soft preferential orientation along <110>.The broad peaks correspond to the amorphous alumina [20].…”

Section: Please Cite This Article As Doi: 101063/15132539mentioning

confidence: 97%

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Sensing anisotropic stresses with ferromagnetic nanowires

Forzani

Gennaro

Koropecki

et al. 2020

Applied Physics Letters

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We have measured the temperature variation of the magnetic anisotropy of Ni nanowires (Ni NW) embedded in freestanding porous anodized aluminum oxide membranes, using DC magnetometry and ferromagnetic resonance. Both techniques show a significant reduction of the uniaxial anisotropy with decreasing temperature. This decrease can be explained by magnetoelastic effects, as Ni NW are subjected to stress due to the difference in thermal expansion coefficients between the nanocomposite materials.Matching our experimental findings with previously measured thermal strains along the Ni NW axis led us to estimate the perpendicular stress. Thus, we postulate the Ni NW as nanometric differential stress sensors.

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Section: Please Cite This Article As Doi: 101063/15132539mentioning

confidence: 72%

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confidence: 67%

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Sensing anisotropic stresses with ferromagnetic nanowires

Forzani

Gennaro

Koropecki

et al. 2020

Applied Physics Letters

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“…The Ni/graphene composites of CG-8 at.% Ni, CG-16 at.% Ni, and CG-24 at.% Ni had a higher temperature expansion coefficient than that of crumpled graphene (see Figure 3 b,c). This is associated with the presence of nickel nanoparticles, since Ni has a greater TEC than graphene (for bulk nickel

=13 × 10

at 300 K [ 95 , 96 ]). As can be seen, before 300 K, there was a difference between the TECs of CG-16 at.% Ni and CG-24 at.% Ni, while, after 300 K, the curves totally coincided.…”

Section: Resultsmentioning

confidence: 99%

Thermal Expansion and Thermal Conductivity of Ni/Graphene Composite: Molecular Dynamics Simulation

2023

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In the present work, the thermal conductivity and thermal expansion coefficients of a new morphology of Ni/graphene composites are studied by molecular dynamics. The matrix of the considered composite is crumpled graphene, which is composed of crumpled graphene flakes of 2–4 nm size connected by van der Waals force. Pores of the crumpled graphene matrix were filled with small Ni nanoparticles. Three composite structures with different sizes of Ni nanoparticles (or different Ni content—8, 16, and 24 at.% Ni) were considered. The thermal conductivity of Ni/graphene composite was associated with the formation of a crumpled graphene structure (with a high density of wrinkles) during the composite fabrication and with the formation of a contact boundary between the Ni and graphene network. It was found that, the greater the Ni content in the composite, the higher the thermal conductivity. For example, at 300 K, λ = 40 W/(mK) for 8 at.% Ni, λ = 50 W/(mK) for 16 at.% Ni, and λ = 60 W/(mK) for 24 at.% Ni. However, it was shown that thermal conductivity slightly depends on the temperature in a range between 100 and 600 K. The increase in the thermal expansion coefficient from 5 × 10−6 K−1, with an increase in the Ni content, to 8 × 10−6 K−1 is explained by the fact that pure Ni has high thermal conductivity. The results obtained on thermal properties combined with the high mechanical properties of Ni/graphene composites allow us to predict its application for the fabrication of new flexible electronics, supercapacitors, and Li-ion batteries.

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“…Thermal expansion of Ni nanowires electrodeposited into self-organized nanoporous amorphous aluminum oxide membranes without an Al substrate has been measured using X-ray diffraction between 110 K and 350 K [7]. An average thermal expansion of the Ni nanowires along the wire axis was found to be…”

Section: Introductionmentioning

confidence: 99%

Anomalous Thermomechanical Behaviour of Carbon Nanotube Bundle

Galiakhmetova¹,

Korznikova²

2021

Rev Adv Mater Tech

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The molecular dynamics method is used to calculate the dependence of pressure on temperature at a constant volume for a bundle of carbon nanotubes (CNTs) considered under plane strain conditions. A chain model with a significantly reduced number of degrees of freedom is used for modeling. The influence of the CNT diameter is analyzed. It was found that for some parameters of the model, the pressure in the CNT bundle can decrease with increasing temperature, which is equivalent to the effect of negative thermal expansion.

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Negative thermal expansion of nanoporous anodic aluminum oxide membranes

Abstract: obtained previously on the thermal expansion of metallic nanowires grown in the nanoporous AAO may be interpreted as originated in a negative thermal expansion of the matrix.

Cited by 7 publications

References 34 publications

Sensing anisotropic stresses with ferromagnetic nanowires

Sensing anisotropic stresses with ferromagnetic nanowires

Thermal Expansion and Thermal Conductivity of Ni/Graphene Composite: Molecular Dynamics Simulation

Anomalous Thermomechanical Behaviour of Carbon Nanotube Bundle

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