We have studied the impact of excitation laser power density on Raman spectrum small-diameter (5−15 nm) silicon nanowires. At low densities, a Lorentzian line is observed at 520 cm-1, same value as that zone center LO (TO) phonon in bulk silicon. With increasing illumination, band downshifts and asymmetrically broadens low-frequency side. Our results contradict traditionally accepted notion downshifted broadened Si nanowires due to quantum confinement effects. Rather, we suggest downshifting...

Multiferroism implies simultaneous presence of more than one ferroic characteristics such as coexistence ferroelectric and magnetic ordering. This phenomenon has led to the development various kinds materials conceptions many novel applications a memory device utilizing multifunctionality multiferroic leading multistate with electrical writing nondestructive reading operations. Though, interdependence electrical- magnetic-order parameters makes it difficult accomplish above thus rendering...

We demonstrate room temperature ferroelectricity in the epitaxial thin films of magnetoelectric gallium ferrite. Piezoforce measurements show a 180\ifmmode^\circ\else\textdegree\fi{} phase shift piezoresponse upon switching electric field indicating nanoscale films. Further, temperature-dependent impedance analysis with and without presence an external magnetic clearly reveals pronounced magnetodielectric effect across transition temperature. In addition, our first principles calculations...

Distinct types of materials are being explored for usage in thermoelectric (TE) and photovoltaic (PV) systems order to alleviate the energy problem. In create nontoxic, more stable, best-performance convergence devices, state-of-the-art hybrid halide double perovskites (HHDPs) compound has been identified as a potential TE material replacement hazardous lead. We have proposed new HHDP (CH 3 NH[Formula: see text]AgInCl 6 performed its theoretical investigation via full linear augmented plane...

Material scientists have stepped up their search for efficient materials in low-cost, high-stability, nontoxic energy conversion devices. In this paper, emerging inspire us to study one of the perovskite chalcogens made from alkaline-earth metals (Barelium). Therefore, we determined some fundamental properties with application-based properties, which explained applicability device fabrication by first-principles calculation within WIEN2K Code. Structure stability has been verified...

Raman scattering studies of crystalline GaP nanowires reveal a strong additional peak in the first order spectrum that can be clearly assigned to surface optical (SO) phonons. The frequency this SO is found sensitive dielectric constant surrounding medium which nanowire embedded. A theory for phonons cylindrical wires presented, mode dispersion ω(q) and experimental are then used predict wavelength dominant Fourier component potential responsible activating mode. Interestingly, phonon agree...

We report here our Raman studies on ${\mathrm{Fe}}_{3\ensuremath{-}x}{\mathrm{Zn}}_{x}{\mathrm{O}}_{4}(x=0,0.015,0.03)$ across the Verwey transition in temperature range 20--300 K. The changes spectra as a function of doping show that are gradual for samples with higher Zn doping. Allen's formula has been used to estimate strength electron-phonon interaction from observed lineshape parameters. These estimates there is strong coupling this system and highest ${T}_{2g}^{3}$ mode comparison...

Double-wall carbon nanotubes (DWNT's) have been studied by Raman scattering using different excitation wavelengths and their spectra compared to those of single wall (SWNT's) ${\mathrm{C}}_{60}$-SWNT peapods. from the radial tangential vibrational modes very small diameter $d\ensuremath{\sim}0.6--0.9 \mathrm{nm}$ secondary (interior) semiconducting tubes within DWNT can be unambiguously identified with 647.1 1064 nm excitations. The frequency displacement these is found downshifted...

Raman scattering experiments on metallic ${\mathrm{La}}_{0.7}$${\mathrm{Sr}}_{0.3}$Mn${\mathrm{O}}_{3}$ have been carried out using different excitation wavelengths as a function of temperature from 15 K to 300 K. Our data suggest mode attributed electronic excitations centered at 2100 ${\mathrm{cm}}^{\ensuremath{-}1}$ whose intensity decreases with increasing temperature. If the is single-particle associated fluctuations mass tensor, decreased would then imply reduction in density states...

Orthorhombic GaFeO3 (o-GFO) with the polar Pna21 space group is a prominent ferrite owing to its piezoelectricity and ferrimagnetism, coupled magnetoelectric effects. Herein, we demonstrate large ferroelectric remanent polarization in undoped o-GFO thin films by adopting either hexagonal strontium titanate (STO) or cubic yttrium-stabilized zirconia (YSZ) substrate. The polarization-electric-field hysteresis curves of c-axis-grown film on SrRuO3/STO substrate show net switching ~35 μC cm−2 an...

Conventional ceramic based piezoelectric materials are brittle, which restricts their use in energy harvesting where flexibility is required. Polymer counterparts flexible but exhibit comparatively reduced electrical output. Here, we provide a method that overcomes these challenges through design of composites comprised polymer matrix (PVDF-TrFE) and filler nanoparticles (niobium-doped Pb(Zr,Ti)O3). Nanoparticles were functionalized with trimethoxysilylpropyl methacrylate (TMSPM) promotes...

A double-walled carbon nanotube is used to study the radial charge distribution on positive inner electrode of a cylindrical molecular capacitor. The outer shell bromine anions. Resonant Raman scattering from phonons each reveals distribution. self-consistent tight-binding model confirms observed Faraday cage effect, i.e., most resides wall, even when this wall was originally semiconducting and metallic.

We have prepared thin films of BiFe1−xZrxO3 (x=0.0–0.15) by chemical solution deposition on Pt/Si substrates. Structural characterization the using x-ray diffraction and Raman spectroscopy suggests lattice distortion upon doping for x<0.15. This also appears to be limit pure phase formation. Ferroelectric measurements reveal that Zr leads reduction in remnant polarization an increase coercive field, attributed distortion. Dielectric indicate doped compositions exhibit absence low...

Here, we report the temperature dependent Raman spectroscopic studies on orthorhombically distorted perovskite YCrO3 over a range of 20–300 K. Temperature dependence DC-magnetization measurements under field cooled and zero protocols confirmed Néel transition at TN ∼ 142 Magnetization isotherms recorded 125 K show clear loop opening without any magnetization saturation up to 20 kOe, indicating coexistence antiferromagnetic (AFM) weak ferromagnetic (WFM) phases. Estimation exchange constants...

Here we report a comprehensive study on the synthesis and characterization of dimethylarsinate-functionalized phosphomolybdates(V), [RPMoV6O15(OH)3{AsO2(CH3)2}3]2- (R = H, HO, CH3, HO2CCH2, HO2CC2H4, C6H5, 4-FC6H4, 4-F3COC6H4) monoanionic mixed-valent heptamolybdate...

We report electron paramagnetic resonance measurements on single crystalline and powder samples of ${\mathrm{Nd}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3}$ across the charge-ordering transition at ${T}_{\mathrm{co}}=240\mathrm{K}$ down to antiferromagnetic ordering ${T}_{N}=140\mathrm{K}.$ The changes in linewidth, g-factor intensity as functions temperature are studied understand nature spin-dynamics system. explain observed large decrease linewidth from ${T}_{N}$ ${T}_{\mathrm{co}}$...

We show that the long-range dipolar interactions in a crystalline cubic polar semiconducting nanowire give rise to an important splitting of Raman-active transverse optic (TO) and longitudinal (LO) phonons at center Brillouin zone. The dipole sums determine two LO TO phonon frequencies are sensitive aspect ratio (L/D), where L D length diameter, respectively. In limit L/D \ensuremath{\rightarrow}\ensuremath{\infty}, we predict for several nanowires. Our calculated results also compared with...

Temperature dependent X-ray diffraction and Raman spectroscopic studies were carried out on the flux grown single crystals of gallium ferrite with Ga:Fe ratio 0.9:1.1. Site occupancy calculations from Rietveld refinement data led to estimated magnetic moment ~0.60 \muB /f.u. which was in good agreement experimental data. Combination these two measurements indicates that there is no structural phase transition material between 18 K 700 K. A detailed line shape analysis mode at ~375 cm^-1...