Size-induced exchange bias in single-phase CoO nanoparticles.

The tuning of exchange bias (EB) in nanoparticles has garnered significant attention due to its diverse range of applications. Here, we demonstrate EB in single-phase CoO nanoparticles, where two magnetic phases naturally emerge as the crystallite size decreases from 34.6 ± 0.

Structural diversity, functional versatility and applications in industrial, environmental and biomedical sciences of polysaccharides and its derivatives - A review.

Recent efforts on the expansion of sustainable and commercial primal matters are essential to enhance the knowledge of their hazards and noxiousness to humans and their environments. For example, polysaccharide materials are widely utilized in food, wound dressing, tissue engineering, industry, targeted drug delivery, environmental, and bioremediation due to their attractive degradability, nontoxicity and biocompatibility. There are numerous easy, quick, and efficient ways to manufacture these materials that include cellulose, starch, chitosan, chitin, dextran, pectin, gums, and pullulan.

Metal to insulator transition, colossal Seebeck coefficient and large violation of Wiedemann-Franz law in nanoscale granular nickel.

We report on the electrical and thermal transport properties of nickel nanoparticles with crystallite size from 23.1 ± 0.3 to 1.

Ultralow Thermal Conductivity and Large Figure of Merit in Low-Cost and Nontoxic Core-Shell Cu@CuO Nanocomposites.

Identification of novel materials with enhanced thermoelectric (TE) performance is critical for advancing TE research. In this direction, this is the first report on TE properties of low-cost, nontoxic, and abundant core-shell Cu@CuO nanocomposites synthesized using a facile and cheap solution-phase method. They show ultralow thermal conductivity of nearly 10 of the copper bulk value, large thermopower of ∼373 μVK, and, consequently, a TE figure of merit of 0.

The effect of lithium on structural and luminescence performance of tunable light-emitting nanophosphors for white LEDs.

Li incorporated tunable YO:Eu red-emitting nanophosphors were synthesized using a wet chemical method. The effect of Li on structural and luminescence properties of the nanophosphors were studied in detail. The structural results exhibited that nanophosphors have a body-centered cubic (I) phase with point group symmetry 3̄.

Enhanced Thermoelectric Performance of Novel Reaction Condition-Induced BiS-Bi Nanocomposites.

This is the first report on the enhanced thermoelectric (TE) properties of novel reaction-temperature () and duration-induced BiS-Bi nanocomposites synthesized using a facile one-step polyol method. They are well characterized as nanorod composites of orthorhombic BiS and rhombohedral Bi phases in which the latter coats the former forming BiS-Bi core-shell-like structures along with independent Bi nanoparticles. A very significant observation is the systematic reduction in electrical resistivity ρ with a whopping 7 orders of magnitude (∼10) with just reaction temperature and duration increase, revealing a promising approach for the reduction of ρ of this highly resistive chalcogenide and hence resolving the earlier obstacles for its thermoelectric application potentials in the past few decades.

Influence of surfactant, particle size and dispersion medium on surface plasmon resonance of silver nanoparticles.

Clear influence of particle size, surfactants and dispersion medium on surface plasmon resonance (SPR) features of Ag nanoparticles (NPs), synthesized in thermal decomposition method, in the broad range of ultraviolet (UV) radiation, critical for many potential applications such as a photocatalyst, UV-sensor and detector, has been demonstrated here. It involves adsorbate coverage, interparticle distance or agglomeration, surface charge density and solvent refractive index (µ). NP agglomeration and surface charge density in solvents of varying µ have been studied systematically through zeta-potential (ζ) and hydrodynamic diameter (HD) using dynamic light scattering (DLS).

A load-based thermopower measurement setup in the temperature range of 5-330 K.

This is a report on the development of an automated precision load-based measurement setup for thermoelectric power (S) of different types of samples in the temperature range of 5-330 K. The problems in the old spring-based setup have been solved in this load-based setup. This setup takes nearly 4 h for each run, and the typical error is within 5%.

Thermoelectric properties of Ag-doped CuS nanocomposites synthesized by a facile polyol method.

We report the first thermoelectric properties of CuAgS, x = 0-0.75 nanocomposites, synthesized by using a facile polyol method. Systematic characterizations using powder XRD, Rietveld refinement of XRD, EDAX, XPS and Raman spectroscopy confirmed their single phase, hexagonal crystal structure with the space group P6/mmc, nominal elemental composition, valence states of the constituent elements and stoichiometric nature.

The effect of stoichiometry on the structural, thermal and electronic properties of thermally decomposed nickel oxide.

A thermal decomposition route with different sintering temperatures was employed to prepare non-stoichiometric nickel oxide (Ni O) from Ni(NO)·6HO as a precursor. The non-stoichiometry of samples was then studied chemically by iodometric titration, wherein the concentration of Ni determined by chemical analysis, which is increasing with increasing excess of oxygen or reducing the sintering temperature from the stoichiometric NiO; it decreases as sintering temperature increases. These results were corroborated by the excess oxygen obtained from the thermo-gravimetric analysis (TGA).

Correction: Influence of particle size and dielectric environment on the dispersion behaviour and surface plasmon in nickel nanoparticles.

Correction for 'Influence of particle size and dielectric environment on the dispersion behaviour and surface plasmon in nickel nanoparticles' by Vikash Sharma et al., Phys. Chem.

Influence of particle size and dielectric environment on the dispersion behaviour and surface plasmon in nickel nanoparticles.

Nickel nanoparticles (NPs) are promising candidates for various applications, including biomedical ones, as they have good magnetic properties as well as high thermal conductivity. We used well-characterized Ni NPs of average Scherrer sizes from 1.31 nm to 22.

Large power factor and anomalous Hall effect and their correlation with observed linear magneto resistance in Co-doped Bi2Se3 3D topological insulator.

Magnetoresistance (MR), thermo power, magnetization and Hall effect measurements have been performed on Co-doped Bi2Se3 topological insulators. The undoped sample shows that the maximum MR as a destructive interference due to a π-Berry phase leads to a decrease of MR. As the Co is doped, the linearity in MR is increased.

Trioctylphosphine as self-assembly inducer.

Nickel nanoparticles (NPs) of different shapes and sizes in polydispersed as well as monodispersed forms were synthesized using trioctylphosphine (TOP), triphenylphosphine (TPP), oleylamine (OA) and their combinations as surfactants to study their self-assembly inducing capabilities. Randomly agglomerated polydispersed NPs were found for TPP and OA, and TPP or OA separately. However, in consolidation with the earlier report of Singh et al.

Enhanced thermoelectric properties of selenium-deficient layered TiSe(2-x): a charge-density-wave material.

In the present work, we report on the investigation of low-temperature (300-5 K) thermoelectric properties of hot-pressed TiSe2, a charge-density-wave (CDW) material. We demonstrate that, with increasing hot-pressing temperature, the density of TiSe2 increases and becomes nonstoichiometric owing to the loss of selenium. X-ray diffraction, scanning electron microscopy, and transimission electron microscopy results show that the material consists of a layered microstructure with several defects.

Luminescence properties of Eu3+ doped CaMoO4 nanoparticles.

When Eu(3+) ions occupy Ca(2+) sites of CaMoO(4), which has a body centered tetragonal structure with inversion symmetry, only the magnetic dipole transition ((5)D(0)→(7)F(1)) should be allowed according to Judd-Ofelt theory. Even if there are a few distortions in the Eu(3+) environment, its intensity should be more than that of the electric dipole transition ((5)D(0)→(7)F(2)). We report here the opposite effect experimentally and ascribe this to the polarizability effect of the MoO(4) tetrahedron, which is neighboring to EuO(8) (symmetric environment).

High coercive field and magnetization reversal in core-shell cum nanotwin driven Ni/NiO nanospheres.

We report here nanotwin-core-shell Ni(core)NiO(shell) spheres of average size 25 nm prepared through polyol method. They exhibit high coercive field at 2 K, sharp peak at approximately 20 K in magnetization curve and magnetization reversal. Interestingly, exchange bias due to antiferromagnetic NiO shell is absent.

Resistivity and thermopower measurement setups in the temperature range of 5-325 K.

Automated precision measurement setups for electrical resistivity of eight metallic samples simultaneously and thermoelectric power of different types of samples in the temperature range of 5-325 K have been developed. The details of the setups and their capabilities have been described. Usually each run takes nearly 5 h and typical error is within 3% and 4%, respectively.

Grain size effect on lattice of ni nanocrystals prepared through polyol method.

Nanocrystalline nickel powders were prepared with grain size 'd' in the range 40-100 nm diameters through polyol method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used for characterization. XRD of the prepared samples consistently matched with standard fcc structure of nickel without any impurity peak.

Thickness dependent structural, electronic, and optical properties of Ge nanostructures.

In the present paper, we have investigated structural, optical as well as electronic properties of electron beam evaporated Ge thin films having layer thicknesses ranging from ultra-thin (5 nm) to thick (200 nm). The Raman spectra show that all peaks are shifted towards lower wave number as compared to their bulk counterparts and are considered as a signature of nanostructure formation and quantum confinement effect. The Raman line exhibits transformation from nanocrystalline to microcrystalline phase with a reduction in blue shift of peak position with increase in Ge film thickness (>5 nm).

Anomalous electrical transport behavior in nanocrystalline nickel.

We have prepared nanocrystalline Ni (n-Ni) samples of grain sizes 40-100 nm using a polyol method and investigated the electrical transport on their compacted pellets in the temperature range 3-300 K. The resistivity, ρ, decreases nearly linearly with increase in compaction pressure but without a change in its slope, dρ/dT. ρ is anomalously large, and is strongly temperature and grain-size dependent.