ZnO-decorated SiC@C hybrids with strong electromagnetic absorption

• Liqun Duan,
• Zhiqian Yang,
• Yilu Xia,
• Xiaoqing Dai,
• Jian’an Wu and
• Minqian Sun

Beilstein J. Nanotechnol. 2023, 14, 565–573, doi:10.3762/bjnano.14.47

• account for this phenomenon. Actually, the dielectric relaxation process of electromagnetic waves in the SCZ samples can be well explained by the Debye theory [37]. According to this theory, the relationship between ε′ and ε″ can be expressed as: where εs and ε∞ are the static and relative the dielectric

• permittivity at the high-frequency limit, respectively. Thus, the plot of ε′ and ε″ is a single semicircle, generally denoted as the Cole–Cole semicircle. At least one dielectric relaxation process occurs when a semicircle arises. Figure 6 shows obvious semicircles under different conditions, especially at a

Plasmonic nanotechnology for photothermal applications – an evaluation

• A. R. Indhu,
• L. Keerthana and
• Gnanaprakash Dharmalingam

Beilstein J. Nanotechnol. 2023, 14, 380–419, doi:10.3762/bjnano.14.33

• since the dielectric strength of a grain is lower than a grain boundary, the dielectric permittivity decreases with decreasing grain size [48]. Moreover, the interaction between plasmonic nanoparticles and substrates on which they are deposited cannot be ignored. The polarization of charges in the

A distributed active patch antenna model of a Josephson oscillator

• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2023, 14, 151–164, doi:10.3762/bjnano.14.16

• is the relative dielectric permittivity of the insulation layer between the patch electrodes. The other size, b, is adjustable and strongly affects the patch antenna performance. For b ≪ λ0, the radiative conductance per slot is given by Equation 5. In the opposite limit, it becomes [36] One of the

Coherent amplification of radiation from two phase-locked Josephson junction arrays

• Mikhail A. Galin,
• Vladimir M. Krasnov,
• Ilya A. Shereshevsky,
• Nadezhda K. Vdovicheva and
• Vladislav V. Kurin

Beilstein J. Nanotechnol. 2022, 13, 1445–1457, doi:10.3762/bjnano.13.119

• dielectric permittivity of silicon). Under this condition, the fundamental resonant mode can be excited in the substrate between the arrays. This condition is beneficial for inter-array coupling. Numerical Calculations The experimental results presented above show that phase locking of two large JJ arrays is

• contains two identical JJ arrays arranged on a common substrate with a dielectric permittivity of ε = 12, close to that of silicon. The lateral dimensions of the substrate are 2 × 0.6 mm while the thickness is 0.3 mm. We chose such a narrow substrate to avoid excitation of transverse resonant modes inside

• containing 100 JJs. The dimensions of the substrate (x × y × z) are 2.0 × 0.6 × 0.3 mm, and its dielectric permittivity is ε = 12. The inductances have the value 100 pH while the internal resistance of the power supplies is 90 Ω. The junctions are described in the RSJ model [20] with parameters Ic = 2.5 mA

Ultrafast signatures of magnetic inhomogeneity in Pd_1−xFe_x (x ≤ 0.08) epitaxial thin films

• Andrey V. Petrov,
• Sergey I. Nikitin,
• Lenar R. Tagirov,
• Amir I. Gumarov,
• Igor V. Yanilkin and
• Roman V. Yusupov

Beilstein J. Nanotechnol. 2022, 13, 836–844, doi:10.3762/bjnano.13.74

• dielectric permittivity tensor of a medium proportional to its magnetization. Therefore, any of the real θK (rotation angle) or imaginary ηK (ellipticity) parts of the complex Kerr angle ΘK = θK + iηK provide a measure of the magnetization of a medium. An ability to track modifications of these quantities on

Design aspects of Bi₂Sr₂CaCu₂O_8+δ THz sources: optimization of thermal and radiative properties

• Mikhail M. Krasnov,
• Natalia D. Novikova,
• Roger Cattaneo,
• Alexey A. Kalenyuk and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 1392–1403, doi:10.3762/bjnano.12.103

• electrode and whisker is set to ≃6 × 105 (Ω·m)−1 and the relative dielectric permittivity of the substrate is εr = 10. First we consider the case without dielectric losses, tan(δ) = 0. The middle panels in Figure 6 show the local distributions of electric field amplitudes in the xz crosssection through the

High permittivity, breakdown strength, and energy storage density of polythiophene-encapsulated BaTiO₃ nanoparticles

• Adnanullah Khan,
• Amir Habib and
• Adeel Afzal

Beilstein J. Nanotechnol. 2020, 11, 1190–1197, doi:10.3762/bjnano.11.103

• the ac frequency at room temperature. The variation of the frequency-dependent complex dielectric permittivity is shown in Figure 6a. The real part of the complex dielectric permittivity of all three samples exhibits a relatively low frequency dependence in the 100–1000 kHz range. The rate of

• at maximum frequency are 30.2, 25.2, and 5.6, respectively. The frequency dependence of the dielectric loss tangent is shown in Figure 6b. The dielectric loss tangent represents the energy loss within the dielectric medium. Contrary to the dielectric permittivity, the loss tangent exhibits

Rapid thermal annealing for high-quality ITO thin films deposited by radio-frequency magnetron sputtering

• Petronela Prepelita,
• Ionel Stavarache,
• Doina Craciun,
• Florin Garoi,
• Catalin Negrila,
• Beatrice Gabriela Sbarcea and
• Valentin Craciun

Beilstein J. Nanotechnol. 2019, 10, 1511–1522, doi:10.3762/bjnano.10.149

• treated ITO films is essential in assessing the advantages of the RTA procedure. To obtain information on the bandgap width, absorption coefficient, refractive index, extinction coefficient, dielectric permittivity, position of the impurity levels in the bandgap and characteristics of the optical

• carriers, N, the real and imaginary parts of the complex dielectric permittivity characterizes the transparency of thin films to electromagnetic radiation (see Figure 9a,b). Thus, when the imaginary part, ε'', can be neglected, the layer is transparent to electromagnetic radiation. The dependence of the

• real and imaginary parts of the dielectric permittivity on the wavelength is illustrated in Figure 8. The increase in thickness of the ITO films influenced the optical constants (i.e., Drude damping coefficient, Drude frequency, complex permittivity, refractive indices, extinction coefficients

Electromagnetic analysis of the lasing thresholds of hybrid plasmon modes of a silver tube nanolaser with active core and active shell

• Denys M. Natarov,
• Trevor M. Benson and
• Alexander I. Nosich

Beilstein J. Nanotechnol. 2019, 10, 294–304, doi:10.3762/bjnano.10.28

• εmet(λ) = −εhost where εhost > 0 is the relative dielectric permittivity of the host medium – see [1][2] for details. If the host medium is air, then the corresponding wavelength is found in the ultraviolet range for silver and in the green range for gold where the bulk losses in metals are

• modes. Note also that there exist other LEP-like formulations aimed at the extraction of mode threshold [28][29][30][31][32]; some of them differ from LEP only by the choice of the material-gain parameter, which can be the imaginary part of the dielectric permittivity (because Im εa = 2αγ, where α is

• transcendental Equation 5 numerically, we use an iterative Newton-type algorithm that needs some initial guess values of the unknown wavelength λ and threshold gain γ. Because of the strong dispersion of the dielectric permittivity of silver, it is convenient to take these initial values after plotting the color

Electrostatic force microscopy for the accurate characterization of interphases in nanocomposites

• Diana El Khoury,
• Richard Arinero,
• Jean-Charles Laurentie,
• Mikhaël Bechelany,
• Michel Ramonda and
• Jérôme Castellon

Beilstein J. Nanotechnol. 2018, 9, 2999–3012, doi:10.3762/bjnano.9.279

• deduced by comparison of experimental data and numerical simulations, as well as the interface state of silicone dioxide layers. Keywords: atomic force microscopy; building-block materials; dielectric permittivity; electrostatic force microscopy; finite element simulation; interphases; nanocomposites

• gradients. A proper interpretation of EFM results allows for the determination of the dielectric permittivity and dimensions of the sample components. Importantly, EFM is particularly suitable for electrical insulators, as opposed to electron microscopy where the rough specimen preparation procedures and

• , the authors hypothesized that an interphase with lower permittivity than that of particles and fillers surrounds the particles. However, the authors did not compare this remarkable change in local dielectric permittivity with macroscopic dielectric spectroscopy measurements. Nevertheless, the

In situ characterization of nanoscale contaminations adsorbed in air using atomic force microscopy

• Jesús S. Lacasa,
• Lisa Almonte and
• Jaime Colchero

Beilstein J. Nanotechnol. 2018, 9, 2925–2935, doi:10.3762/bjnano.9.271

• , h is the total thickness of the dielectric films on tip and sample, ε0 is the dielectric permittivity of vacuum and ε is the relative dielectric constant [43][44][45][46]. For a purely metallic system in air or vacuum were no dielectric layer is present (h = 0), the expression simplifies to C″(d

Interaction-induced zero-energy pinning and quantum dot formation in Majorana nanowires

• Samuel D. Escribano,
• Alfredo Levy Yeyati and
• Elsa Prada

Beilstein J. Nanotechnol. 2018, 9, 2171–2180, doi:10.3762/bjnano.9.203

• and the unavoidable presence of disorder [38]. If this is the case, it is then characterized by a finite effective dielectric permittivity which depends on the SC shell width as well as its composition, as we show in Section 1 of Supporting Information File 1. Some experiments [39] have reported that

• show how the width of the pinning plateau evolves with VZ when we change the chemical potential, the dielectric permittivity or the width of the SC shell, and the aspect ratio of the nanowire section. We find that pinning remains for any chemical potential, while it vanishes when the attractive

Formation and development of nanometer-sized cybotactic clusters in bent-core nematic liquid crystalline compounds

• Yuri P. Panarin,
• Sithara P. Sreenilayam,
• Jagdish K. Vij,
• Anne Lehmann and
• Carsten Tschierske

Beilstein J. Nanotechnol. 2018, 9, 1288–1296, doi:10.3762/bjnano.9.121

• clusters (NcybC) of the SmC type as explained above. The second compound, BCN84, has two asymmetrical alkyl chains of different lengths and is of the same molar mass as BCN66. The dielectric permittivity measurements were carried out using a broadband alpha high-resolution dielectric analyzer (Novocontrol

• the high frequency dielectric permittivity that depends on the electronic and atomic polarizability of the material, ω = 2πf is the angular frequency of the probe field, ε0 is the permittivity of free space, σDC is DC conductivity, τj is the relaxation time of the jth process, Δεj is the dielectric

Nanoscale mapping of dielectric properties based on surface adhesion force measurements

• Ying Wang,
• Yue Shen,
• Xingya Wang,
• Zhiwei Shen,
• Bin Li,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 900–906, doi:10.3762/bjnano.9.84

• liquid interfacial tension, θ0 is the contact angle at zero external voltage, and d, εr and ε0 are the thickness, relative permittivity of the dielectric layer, and the absolute dielectric permittivity of vacuum, respectively. Hence, the adhesion force between the AFM tip and the sample is affected by

Effect of ferroelectric BaTiO₃ particles on the threshold voltage of a smectic A liquid crystal

• Abbas R. Imamaliyev,
• Mahammadali A. Ramazanov and
• Shirkhan A. Humbatov

Beilstein J. Nanotechnol. 2018, 9, 824–828, doi:10.3762/bjnano.9.76

• features observed in the C–V characteristics are given. Keywords: colloidal systems; dielectric permittivity; ferroelectric BaTiO3 particles; smectic A liquid crystals; threshold voltage; Introduction Interest in liquid crystals (LC) as a unique state of matter arises not only from a scientific point of

• electro-optical cell. The electro-optical effect changes the effective dielectric permittivity of LC, which is reflected a change of capacitance of the electro-optical cell. The electro-optical effect in the investigated LC is the planar–homeotropic transition due to the positive dielectric anisotropy of

• effective dielectric permittivity starts to increase. Note that the latter is determined as the ratio ε = C/C0, where C and C0 are the capacitances of the filled cell and an empty cell, respectively. Figure 3 presents the effective dielectric permittivity as a function of the voltage for pure smectic A LC

Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields

• Emil Petrescu,
• Cristina Cirtoaje and
• Octavian Danila

Beilstein J. Nanotechnol. 2018, 9, 399–406, doi:10.3762/bjnano.9.39

• threshold, the deviation angle is very small and the free energy caused by the elastic forces is: where K1 and K3 are the splay and bent elastic constants and θz = ∂θ/∂z. Due to the presence of the QDs, the electric properties of the mixture change. Hence, instead of perpendicular dielectric permittivity

Dynamic behavior of a nematic liquid crystal with added carbon nanotubes in an electric field

• Emil Petrescu and
• Cristina Cirtoaje

Beilstein J. Nanotechnol. 2018, 9, 233–241, doi:10.3762/bjnano.9.25

• crystal with the electric field (Figure 2) is: where Here is the transverse component of the dielectric permittivity and is the dielectric anisotropy of the liquid crystal. Since D, the electric displacement, is constant, the voltage between the electrodes can be written as: and Equation 7 becomes: If

Dielectric properties of a bisimidazolium salt with dodecyl sulfate anion doped with carbon nanotubes

• Doina Manaila Maximean,
• Viorel Cîrcu and
• Constantin Paul Ganea

Beilstein J. Nanotechnol. 2018, 9, 164–174, doi:10.3762/bjnano.9.19

• functions. As a result of doping the ILC with CNT, the electric conductivity increases significantly. Ionic conductivity is dominant and it was indirectly observed through the electrode polarization (EP) effect. The very high dielectric permittivity values and the decrease of the electric conductivity at

• dielectric permittivity of a medium. For a sinusoidal electric field Equation 3 becomes: The real and the imaginary parts are σ′(ω) = σ0 + ωε0ε″(ω) and σ″(ω) = ωε0ε′(ω), respectively. As shown in Figure 11, at medium frequencies (103–105 Hz), the ac conductivity and permittivity spectra are controlled by ion

• permittivity and electric conductivity spectra is complex, due to the superposition of ionic conductivity effect and dipolar relaxation specific to LC. Ionic conductivity is dominant and its effects are indirectly seen through the electrode polarization (EP) effect. (2) The very high dielectric permittivity

Electrical properties of a liquid crystal dispersed in an electrospun cellulose acetate network

• Doina Manaila Maximean,
• Octavian Danila,
• Pedro L. Almeida and
• Constantin Paul Ganea

Beilstein J. Nanotechnol. 2018, 9, 155–163, doi:10.3762/bjnano.9.18

• the frequency range from 10−1 to 107 Hz, in a temperature domain from 293 to 350 K. The DS results were obtained by plotting the real and imaginary components of the complex permittivity function ε*(ω) = ε′(ω) − iε″(ω). Here, ε*(ω) is the dielectric permittivity, the real part, ε′(ω), is the

• composite system has an important influence on the values of dielectric permittivity (Figure 5). Moreover, because of the interaction with the surface of the CA fibers, the dynamics of the E7 molecules is more or less attenuated, as compared to the pure LC. Thus, as in other composite systems, the phase

Nematic liquid crystal alignment on subwavelength metal gratings

• Irina V. Kasyanova,
• Artur R. Geivandov,
• Vladimir V. Artemov,
• Maxim V. Gorkunov and
• Serguei P. Palto

Beilstein J. Nanotechnol. 2018, 9, 42–47, doi:10.3762/bjnano.9.6

• to the principal refractive index corresponding to the dielectric permittivity tensor component along the LC director ( = 1.751 at 546 nm). Thus, we can conclude that for the given short-period grating we achieve a quite good planar alignment when the pretilt angle (in the cases where it exists) is

Impact of titanium dioxide nanoparticles on purification and contamination of nematic liquid crystals

• Dmitrii Pavlovich Shcherbinin and
• Elena A. Konshina

Beilstein J. Nanotechnol. 2017, 8, 2766–2770, doi:10.3762/bjnano.8.275

• the range from 20 Hz to 1 kHz. In this spectral range, the dispersion of dielectric permittivity is related to ionic conductivity. Figure 1a represents real and imaginary parts of the dielectric permittivity of initially low-contaminated liquid crystals (LC1) and their composites with TiO2

• (Figure 1b). Doping LC2 with TiO2 NPs resulted in a reduction of the real and imaginary parts of the dielectric permittivity. This indicates a decrease of the ionic conductivity of LC2. In this frequency range, the spectra of the dielectric permittivity can be approximated by following equations [24

• ]: where сi – ion density, q – elementary charge, D – average diffusion coefficient, ε0 – dielectric constant, d – thickness of the cell gap, kB – Boltzmann factor, T – temperature, f – frequency, and ε∞ – high-frequency dielectric permittivity. We have evaluated the ion density and the average diffusion

Alternating current magnetic susceptibility of a ferronematic

• Natália Tomašovičová,
• Jozef Kováč,
• Veronika Gdovinová,
• Nándor Éber,
• Tibor Tóth-Katona,
• Jan Jadżyn and
• Peter Kopčanský

Beilstein J. Nanotechnol. 2017, 8, 2515–2520, doi:10.3762/bjnano.8.251

• , the threshold voltage of the reorientational response is just a few volts, owing to the relatively large anisotropy of the dielectric permittivity. Analogous effects exist with magnetic fields. However, the threshold magnetic fields are high (B = μ0H ≈ 1 T) as a consequence of the small diamagnetic

Parylene C as a versatile dielectric material for organic field-effect transistors

• Tomasz Marszalek,
• Maciej Gazicki-Lipman and
• Jacek Ulanski

Beilstein J. Nanotechnol. 2017, 8, 1532–1545, doi:10.3762/bjnano.8.155

• insulating material. The capacitance is determined by the dielectric permittivity (ε) and the thickness of the insulating layer. Currently, two types of dielectric materials are commonly employed in transistor design and construction, either inorganic metal oxides (such as Ta2O5, Al2O3, SiO2) or organic

• polymers [13]. However, it was found that the application of an inorganic insulator with high ε significantly decreases the mobility of charge carriers by interaction with the induced polarization in the gate insulator [37]. The effect of dielectric permittivity of the gate insulating material on field

• the linear regime. To summarize, it should be pointed out that an increase of dielectric permittivity of gate insulating material results in a decrease of field effect mobility (Figure 7b). For all dielectric materials applied, the highest values of charge carrier mobility were obtained for xylylene

Near-field surface plasmon field enhancement induced by rippled surfaces

• Mario D’Acunto,
• Francesco Fuso,
• Ruggero Micheletto,
• Makoto Naruse,
• Francesco Tantussi and
• Maria Allegrini

Beilstein J. Nanotechnol. 2017, 8, 956–967, doi:10.3762/bjnano.8.97

• resonances on metallic nanometer-scale structures is an intrinsically nanoscale phenomenon, given that the two resonance conditions (i.e., negative dielectric permittivity and large free-space wavelength in comparison with system dimensions) are realized at the same time on the nanoscale. Resonances on

Localized surface plasmons in structures with linear Au nanoantennas on a SiO₂/Si surface

• Ilya A. Milekhin,
• Sergei A. Kuznetsov,
• Ekaterina E. Rodyakina,
• Alexander G. Milekhin,
• Alexander V. Latyshev and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2016, 7, 1519–1526, doi:10.3762/bjnano.7.145

• thickness less than or equal to 100 nm formed on a silicon substrate. The dielectric functions of SiO2 and Si used in the simulations were taken from [37]. Gold was modeled as a lossy dispersive medium with the dielectric permittivity εAu described by the classical Drude formula: where ν is the radiation