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Phase stability and dynamics of entangled polymer-nanoparticle composites
Nanoparticle–polymer composites, or polymer–nanoparticle composites (PNCs), exhibit unusual mechanical and dynamical features when the particle size approaches the random coil dimensions of the host polymer. Here, we harness favourable enthalpic interactions between particle-tethered and free, host polymer chains to create model PNCs, in which spherical nanoparticles are uniformly dispersed in high molecular weight entangled polymers. Investigation of the mechanical properties of these model PNCs reveals that the nanoparticles have profound effects on the host polymer motions on all timescales. On short timescales, nanoparticles slow-down local dynamics of the host polymer segments and lower the glass transition temperature. On intermediate timescales, where polymer chain motion is typically constrained by entanglements with surrounding molecules, nanoparticles provide additional constraints, which lead to an early onset of entangled polymer dynamics. Finally, on long timescales, nanoparticles produce an apparent speeding up of relaxation of their polymer host.
Phase stability, electronic, mechanical, lattice distortion, and thermal properties of complex refractory-based high entropy alloys TiVCrZrNbMoHfTaW with varying elemental ratios
This study examines the intricate area of refractory-based high entropy alloys (RHEAs), focusing on a series of complex compositions involving nine diverse refractory elements: Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W.
Evidence of improved ferroelectric phase stabilization in Nd and Sc co-substituted BiFeO{sub 3}
Polycrystalline BiFeO{sub 3} and Bi{sub 0.9}Nd{sub 0.1}Fe{sub 1−x}Sc{sub x}O{sub 3} (x = 0, 0.05, and 0.10) multiferroic compounds were prepared using conventional solid-state route. X-ray diffraction studies and Raman measurements indicated that the compounds were crystallized in rhombohedral structure with R3c space group. Weak ferromagnetism was induced due to the suppression of canted spin structure in the substituted compounds. Both remanent magnetization (M{sub r}) and coercive field (H{sub c}) were enhanced in Nd and Sc substituted compounds. Further, Néel temperature T{sub N} was decreased from 644 K for BiFeO{sub 3} to 550 K for Bi{sub 0.9}Nd{sub 0.1}Fe{sub 0.9}Sc{sub 0.1}O{sub 3} compound due to weakening of magnetic exchange interactions between B-site cations in the substituted compounds. Enhanced and nearly well saturated electrical polarizations were observed in Sc substituted compounds, which are attributed to the strengthening of covalent hybridization between Bi and O ions and reduction in oxygen vacancies. The remnant polarization was enhanced to 12.5 μC/cm{sup 2} in Bi{sub 0.9}Nd{sub 0.1}Fe{sub 0.9}Sc{sub 0.1}O{sub 3} compound. Impedance studies revealed that insulating character of substituted compounds is enhanced and electrical relaxations are of non-Debye type.
First-principles study of phase stability of stoichiometric vanadium nitrides
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Structures, phase stabilities, and electrical potentials of Li-Si battery anode materials
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Phase stability and properties of manganese oxide polymorphs: Assessment and insights from diffusion Monte Carlo
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Quantum anomalous Hall phase stabilized via realistic interactions on a kagome lattice
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Phase stability in the three-dimensional open-source code for the chiral mean-field model
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