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Multiferroic nanomaterials bear draw attention plenty consideration on account of the mixture of two or more determinants, in the way that ferroelectricity, ferromagnetism, and ferroelasticity, giving an expansive range of professional, depressed capacity, environmentally intimate request. Nano-bismuth ferrite (BiFeO3, BFO) exhibits two together (anti) ferromagnetic and ferroelectric real estate at room temperature. Therefore, it bears risk a very influential part fashionable the multiferroic foundation. This review focuses ahead of the progress of nano-BFO objects, containing unification, facial characteristics, structures, and potential uses of multiferroic order accompanying novel functions. Hopes and danger happen all investigated and made clear. We hope that this review will be a part of a review and encourage more research workers to win accompanying nano-BFO results.

Bi1-xSmxFeO3 (x = 0.00, 0.05, 0.15) nanoparticles have been prepared through tartaric acid assisted sol–gel method. The X-ray diffractogram was used to confirm the phase formation and it revealed the single-phase formation with R3c space group. SEM analysis revealed that the particle size decreased with increasing Sm concentration. The crystallite size was observed to be in the range of 30 nm. M-H study depicted an increase in magnetization with increasing samarium concentration. Electron paramagnetic resonance (EPR) of magnetization studies was found to be in agreement with results of the vibrating sample magnetometer (VSM) magnetization studies.

Multiferroics are the materials having ferroelectric and magnetic properties simultaneously and can be tuned by controlling electric and magnetic field for the desired applications. Pure and samarium-doped bismuth ferrite nanoparticles Bi1−xSmxFeO3 (BSFO x = 0, 0.05, 0.10, 0.15, 0.20) with varied doping concentrations have been synthesized using sol–gel technique. The effect of doping on structural, morphological, elemental composition and optical properties were analyzed using various characterization techniques. X-ray diffraction (XRD) analysis of Bi1−xSmxFeO3 samples show the compressive lattice distortion and structural phase transformation from rhombohedral to orthorhombic phase. The Rietveld refinement shows that the crystalline structure of pristine BiFeO3 (BFO) is typical rhombohedral structure with R3c space group. Scanning electron micrograph (SEM) reveals that with increasing Sm concentration the grain size decreases up to ~ 30 nm. XRD and SEM analysis confirmed the synthesized samples having pure phase formation and nanocrystalline nature. Ultraviolet–Visible (UV–Vis) spectra of the samples show that the enhanced visible light absorption would be a promising material for photocatalytic application. The findings of X-ray photoelectron spectroscopy (XPS) verify the effective Sm doping in BFO samples.

Tunnelling is a quantum mechanical effect which becomes significant in plasmonic systems with nanogap regions. In a system of closely spaced metal nanoparticles plasmon tunnelling plays an important role in the transfer of energy and hence governs the optical properties of the system. Plasmon assisted tunnelling through a system depends on the skin depth of the material in consideration, which in turn is controlled by the wavelength of incident light. Here, we present, ‘gradient potential dependent skin-depth theory (GPST)’ explaining resonant plasmons assisted tunnelling through metal nanoparticles for the operating wavelength of 1.1 μm. For a system of silver nanodisk dimer with sub-nanometer interparticle distance, the nanogap region between adjacent nanodisks give rise to gradient potential forming the tunnelling zone and is verified by finite difference time domain computational method. The energy eigenvalues and corresponding eigen frequencies are obtained for the dimer system. The proposed GPST can predict the behaviour of plasmon tunnel diode, plasmonic Josephson junction assisted superconductivity, plasmon tunnelled field-effect transistors etc. significantly improving the performance of integrated circuits.

The influence of novel Cd-Ni co-substituted BiFeO3 (BFO) on structural, magnetic, optical and photocatalytic properties of nanoparticles were studied. Samples were prepared using tartaric acid modified sol-gel technique. Doping-induced structural distortion from rhombohedral to orthorhombic phase was confirmed by XRD and Raman results. The crystallite size decreases from 16.49 to 11.23 nm with increasing the dopant concentration. Morphological studies using HR-SEM revealed that the average particle size decreased significantly from 91.90 to 53.52 nm. EDX studies were used to validate the sample elemental analysis. Furthermore, the effective co-substitution of Cd-Ni into the bismuth ferrite lattice improved the saturation magnetization from 0.096 emu/g to 2.420 emu/g. The XPS confirmed the dominance of the Fe3+ oxidation state. The optical bandgap of BFO nanoparticles could be tuned by Cd-Ni co-doping from 2.06 eV to 1.75 eV. Also, Bi1-xCdxFe1-xNixO3 (BCFNO-6) sample demonstrated the best Methylene blue (MB) and Rhodamine B (RhB) degradation activity under UV-visible irradiation.

Bi1-xSmxFeO3 (BSFO, x = 0, 0.05, 0.10, 0.15, 0.20) nanoparticles were prepared through tartaric acid-modified sol-gel technique. X-ray diffraction and scanning electron microscopy provide phase purity and nanocrystalline behavior (29–92) nm of pristine and doped BFO nanoparticles. The crystallite sizes of the studied samples ranged from 19.64 nm to 12.26 nm. The Rietveld refinement of XRD data demonstrated a good configuration of change in the crystalline structure. Structural phase analysis by XRD suggested that structural transformation from rhombohedral structure (R3c space group) to orthorhombic structure (Pnma space group) is observed in Sm substituted BFO nanoparticles. The ferromagnetic properties increase up to x = 15 % in the samples with enhancing magnetization. A large component of the orthorhombic phase for x = 20 % sample results from a drastic decrease in the ferromagnetic property due to collinear antiferromagnetic ordering correlated with VSM and EPR studies.

In this paper, we propose a design for surface plasmon polariton band gap (SPPBG)-enabled plasmonic Mach–Zehnder interferometer (PMZI) comprising of array of silver nanorods embedded upright into silicon on insulator (SOI) substrate and analyze its potential in sensing, intended for cancer therapy. Periodic arrangement of nanorods embedded into SOI substrate grants strong spatial confinement and assist waveguidance to the propagating plasmon mode due to the SPPBG effect. This arrayed system triggers local field enhancement promoting sensing proficiency of the device and is assessed in terms of wavelength and phase shift. Proposed design of SPPBG-enabled PMZI sensor is successfully employed for detection and classification of various cancerous cells. The structural parameters of PMZI are optimized in compliance with the plasmonic band gap in the range of 400–800 nm yielding exceptionally high sensitivity at input wavelength of 633 nm. Volumetric analysis of the analyte reveals that very small analyte volume of the order of 10−15 cc is sufficient to yield significant phase shift. Phase shift obtained for the breast adenocarcinoma and blood cancer cell lines are 1.2357radian and 0.3351radian, respectively, which read very high value of phase shifts to identify extremely small changes in refractive index of the analyte. Figure of merit calculated thereby expose impressive device performance outdoing preceding plasmonic sensors leading to validation of proposed ultra-compact-sensitive PMZI design.

We propose ultra-compact waveguides for plasmonic circuitry based on silver nanorods array embedded vertically into silicon on insulator (SOI) substrate for nanoscale guidance of optical frequencies. Silver nanorods array palisade silicon to form core of SOI waveguide and is theoretically modeled for the first time. Propagation characteristics of the structure are obtained using finite difference time domain (FDTD) computations, exposing bandgap in the visible regime for transverse magnetic modes and are verified by the plane wave expansion (PWE) method. Narrow transmission bandwidth of ∼10 nm with quality factor and confinement factor of 97.5% and 92% is achieved respectively, confirming strong confinement of the propagating mode at 633 nm and the losses calculated in decible per micrometer (dB/μm) for the waveguide is found to be .75 dB/μm for straight waveguide. Further, Y-splitter designed from the basis equally bifurcate power and the outputs received at the two ends are in phase yielding a viable 50–50 power splitter. Bend design routing light in nano-dimensions is also implemented successfully, offering components for high density plasmonic circuitry.

In this work we propose and study a highly sensitive quantum dot (QD)-metal film plasmonic composite. The system comprises of indium arsenide (InAs) QDs on silver film. The intensity is traced by scanning the absorption spectra for the system. We found that the behaviour of the plasmonic composite changes by varying the thickness of metal film. It is observed that the sensitivity of the composite varies with the thickness of metallic film and the quantum size effects dominate at sub-nanometer gap. The proposed system shows promising applications in lasing, sensing and spectroscopy.

Photonic crystal based nano -displacement se nsor for horizontal as well as vertical displacement has been proposed. The design is highly sensitive in the displacement region 40nm–120nm with sensitivity 0.00461nm -1 for horizontal displacement of the moving PhC waveguide. For vertical displacement of the moving PhC waveguide the design is highly sensitive in the region 150nm-200nm with sensitivity 0.00684nm -1 for zero horizontal displacement, 130nm-200nm with sensitivity 0.00523 nm -1 for 10nm horizontal displacement, 130 nm-200nm with sens itivity 0.00418 nm -1 for 20nm horizontal displacement, 130nm-200nm with sens itivity 0.00461 nm -1 for 30nm horizontal displacement,100nm-130nm with sensitivity 0.00466 nm -1 for 40nm horizontal displacem ent. It has been concluded that the proposed design behaves as a Nano-displacement sensor fo r horizontal displacement of the movi ng PhC waveguide up to the region of displacement of magnitude of 40 0nm and for vertical displacement of the m oving PhC waveguide up to the region of displacement of magnitude of 3 00nm.The proposed design can behave as a na no-Displacement sensor for both horizontal as well as vertical displacement. Keywords: Photonic crystal; nano-disp lacement sensor; Sensitivity

We propose plexcitonic system formed by multi-layered silver-gallium arsenide-silver (Ag-GaAs-Ag) quantum nano-lenses and study optical properties using finite difference time domain method. Plane wave expansion method reveals hybrid band-structure. Cavity defect support strongly confined mode.

In this paper we investigate potential of plasmonic nano switch as a result of Fano-resonance observed in periodically arrayed silver (Ag) nanoparticles embedded over silicon (Si) on insulator (SOI) substrate, by using 3D finite difference time domain (FDTD) method. Structural parameters of the embedded silver nanoparticles were optimized giving rise to plasmon modes in the device. We find that as the device is scanned for a range of wavelength varying from visible to near infra-red, the transmission spectra exhibits Fano-line shape asymmetry for input wavelength regime near 1.3 - 1.55micron, whereas normal resonating peak is observed in the visible region. The optical properties of the switch reveal, enhancement in transmission due to strong plasmonic Fano resonance between the background and resonant processes. Sharp Fano-resonance, specific to interacting quantum systems, is exhibited by the proposed embedded hybrid design of metal nanorods into Si, which meets the condition required for high contrast switches and hence can be exploited as per anticipated results. Fano resonance in this nanorod-substrate system can also be used for designing nanoantennae, lasers, sensors, SERS etc.

Fano-resonance in elliptical silver-nanorods is tuned for yielding high transmission in proposed plasmonic-nanocavity. Spectral distribution for the cavity over a range of wavelength reveals extraordinary transmission for telecom region, promising applications in switching and sensing.

We theoretically investigate compact plasmonic coupler based on metal nanopillar over silicon on insulator substrate demonstrating routing of light at nanoscale. Proposed geometry demonstrates strong mode confinement, allows sharp bends with low loss and easy integration on chip circuitry. The coupler is optimized for visible regime and can be tuned for specific wavelengths. Plasmonic transverse magnetic (TM) modes are observed and examined using finite difference time domain (FDTD) computations. Coupling length (Lc) and gap width (Wc) for the nanopillar assisted four-port plasmonic coupling structure is optimized to give enhanced efficiency. The structure renders subwavelength light manipulation overcoming conventional photonics with applications in plasmonic circuitry for nanoscale guidance of light in data transmission, integrated chip design etc.

A hybrid metal photonic crystal based nanostructured cavity and waveguide for the sub-wavelength confinement of light is proposed and it is shown that a bottom reflector is vital for the vertical emission from a silicon (Si) photonic crystal (PC) nanocavity. A photonic crystal slab of Si (ed=11.56 or nd=3.4) with air holes and metal as an underlying substrate is chosen and three dimensional (3D) photonic bandgap for structure is calculated with plane wave expansion (PWE) method. Using finite difference time domain (FDTD) method, the transmission of a cavity mode as a function of Photonic crystal slab thickness is calculated and it is observed that the transmission increases with the increase in slab thickness at wavelength, m 55 . 1 μ = λ . Also, transverse electric field profiles (Ey) of the cavity mode has been shown and quality factor are calculated for the cavity and possible application in the area of PC light based emitters such as plasmonic lasers and single photon source is assessed.

A plasmonic cavity incorporating surface plasmon polariton(SPP) mode is proposed to be used as infiltrated sensor employing sub-wavelength confinement of light. Truly Plasmonic TM mode is obtained and the mode profile of the Plasmonic Photonic Crystal Cavity (PPCC) structure is shown using three dimensional Finite Difference Time Domain Method (3D-FDTD) method. The cavity length of the structure is optimized to obtain single mode localization of resonating wavelength and the change in the cut-off wavelength is observed by varying refractive indices of the content of air holes. A transverse magnetic (TM) Plasmonic bandgap of the structure is shown and hence, the transmission spectra, Quality factor are calculated.

We examine the propagation of plasmonic TM (Transverse Modes) modes generated in the designed periodic array of silver (Ag) embedded on silicon (Si) substrate. The properties of surface plasmons are tailored by altering the size of Ag nanorods and its periodicity. Conventional waveguides cannot guide electromagnetic energy below the diffraction limit of light, which can be overcome by texturing the metal or dielectric surface. In this hybrid design we have textured the interface by placing metallic, Ag nanorods on Si substrate placed over bilayer system of glasses. This provides the missing momentum required, since SPP modes always lay beyond the light line and has shown strong confinement of light. Ag nanorods are structured at nano dimensions to control and manipulate surface plasmon polariton (SPP) propagation and thus open new possibilities in light matter interaction.

Plasmon like excitation is observed at the interface between one-dimensional periodic array of air holes in silicon (Si) with ferroelectric polyvinylidene fluoride (PVDF) as a substrate to obtain subwavelength confinement of surface Plasmon modes at terahertz (THz) frequencies. A truly Plasmonic TM mode is obtained confined at the interface of PVDF layer and the 1D perforated dielectric slab and the mode field distribution of the structure is demonstrated using three dimensional (3D) Finite Difference Time domain Method (FDTD) method. It is shown that PVDF are promising materials for strongly confined THz wave propagation in Surface Plasmon photonic crystal. The transmission, confinement and hence the propagation length of the plasmonpolariton like terahertz surface modes sustained by the structure are studied using Finite difference time domain (FDTD) method. Further, the propagation characteristics of surface Plasmon polariton (SPP) which can be controlled by the structure geometry is discussed.

One-dimensional (1D) surface plasmonic (SP) nanostructured cavity for the sub-wavelength confinement of light is proposed. Since, the significant spatial confinement of the plasmonic structure is needed for the miniaturization of the device, thin silver metal sheet is used to get plasmonic mode of the cavity. 1D plasmonic photonic crystal structure is designed by placing a silver substrate film(em) below the photonic crystal waveguide of one dimensional array of air holes in Si (e d =11.56 or n d =3.4) slab of finite thickness. TM mode with vertical electric field is investigated and it is observed that the mode remains dominant in the structure. Further, surface plasmonic nano cavity defect mode is studied by changing the cavity length which can be tuned for different wavelengths by changing the geometry of the structure.

Enhancement in the asymmetric line shape of Fano resonance is observed and extensively examined for cavities in plasmonic crystals of ellipsoidal silver nanoparticles with hexagonal arrangement. Scattering models for ellipsoidal and cylindrical nanoparticles are compared and it is found that the spectral interference between the cavity mode and the background scattering mode results in a sharp asymmetric peak, which is the defining characteristic of Fano resonance. It is found that the cavity in ellipsoidal nanoparticles yields high transmission at a wavelength of 1600 nm compared with its cylindrical counterpart. Higher harmonic generation is also observed, which confirms the ultrahigh cavity response in ellipsoidal nanoparticles. The effect of power variation on the Fano resonance profile is described, and its application in the field of switching is explored. In addition, the influence of mutual interparticle coupling on Fano line shapes for transverse electric and transverse magnetic polarization is reported. The extraordinary rise in asymmetric line shapes of the Fano resonance promises profound applications in the field of sensing, switching, and lasing devices.