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In this paper, we have investigated the flicker noise (1/ $f$ ) in 45-nm RFSOI NFETs for quantum computing applications. 1/ $f$ noise characterization and analysis were performed in linear region at cryogenic temperatures down to 10K. A Lorentzian-like noise is also observed depending on bias conditions, possibly due to the floating body of PDSOI. The extracted frequency exponent $(\gamma)$ shows an inverted U-shape behavior with temperature mainly attributed to non-uniform energy distribution of traps in the gate dielectric. The dominant source of 1/ $f$ noise is carrier number fluctuation. Thermal-activation behavior of 1/ $f$ noise is studied, which shows the traps responsible for noise are not thermally activated. Volume trap densities are also extracted from 300K down to 10K. The volume trap density increases with a decrease in temperature, but no significant increase in normalized noise is observed at cryogenic temperatures in the measured NFETs. The non-uniform distribution along with the thermal inactive behavior of traps over the studied temperature range is expected to be a plausible reason for the temperature-independent behavior of normalized noise.

Multifrequency scintillation observations show that strong amplitude scintillations on very high frequency (VHF) signals are accompanied by weak L‐band scintillations near the dip equator and strong L‐band scintillations in equatorial ionization anomaly (EIA) region. For several decades this has been attributed to higher ambient plasma density in the EIA region. Recent work suggests that occurrence of stronger L‐band scintillations in the EIA region requires that the intermediate‐scale (~100 m to few km) ionospheric irregularity spectrum in this region be significantly shallower than that in the equatorial region. However, this has not been established so far. Signal frequency dependence of amplitude scintillations is characterized by the frequency exponent that determines the dependence on signal frequency of the S4 index: the standard deviation of normalized intensity fluctuations. In this paper, theoretical calculations of the frequency exponent for VHF and L‐band signals are carried out using different irregularity spectra and compared with observations in order to characterize power‐law irregularity spectra in different latitude zones. Intermediate‐scale irregularities in the equatorial and low‐latitude region, which are aligned with the geomagnetic field, are described by a two‐dimensional model. Model simulations show that the frequency exponent derived from S4 indices for VHF and L‐band signals is determined only by the characteristics of the irregularity spectrum and hence can be utilized to identify the nature of the power‐law irregularity spectrum. Frequency exponents computed using VHF and L‐band observations near the dip equator and EIA regions show distinct patterns, which clearly indicate steep and shallow irregularity spectra, respectively, in these regions. Key Points: Simulated scintillations show that signal frequency dependence of S4 is determined by irregularity spectrum, not ambient plasma densityFrequency exponent for VHF and L‐band indicates steeper power‐law irregularity spectrum near dip equator than at 10°N geomagnetic latitudeShallow irregularity spectrum found in equatorial ionization anomaly region is critical for strong L‐band scintillations recorded there [ABSTRACT FROM AUTHOR]

In the present work, structural, morphological, dielectrical, and electrochemical properties of LiNixMn(2-x)O4 (where x = 0, 0.1,0.3, 0.5 mol%) prepared by solution combustion method were reported. X-ray diffraction studies confirmed the formation of cubic spinel structure without any impurity phases. Scanning electron micrographs revealed grains of micrometer range with a spherical like morphology and narrow size distribution. Dielectric parameters such as dielectric constant, dielectric loss, impedance, and electrical modulus were found to depend on temperature, frequency, and dopant concentration. AC conductivity was found to increase with increase in temperature exhibiting negative temperature co-efficient of resistance (NTCR) property in the material. Complex impedance and electrical modulus studies revealed the existence of temperature-dependent electrical relaxation in the material. The Correlated Barrier Hopping (CBH) model of conduction mechanism was confirmed by the decrease in s parameter with increase in temperature. Charge-discharge studies revealed the stabilization of spinel lattice by Ni ions, contributing to better capacity retention. [ABSTRACT FROM AUTHOR]

Sr(1−x)(Bi,Li)xTiO3 compound was prepared via a solid-state reaction route with microwave heating of the starting materials. X-ray diffraction analysis revealed pure perovskite phase without formation of any secondary phases. The electrical conductivity was studied as a function of temperature and frequency. The experimental results indicate that the alternating-current (AC) conductivity increased with frequency, following the Jonscher power law. To interpret the possible mechanism for electrical conduction, the correlated barrier hopping model was applied. The effect of temperature and the Bi/Li concentration on the electrical resistivity was studied. The results showed that the electrical resistivity decreased with increasing temperature, which could be due to increased thermal energy of electrons. Also, the electrical resistivity decreased with increase in the amount of Bi and Li, which could be due to increased concentration of structural defects, which could increase the number of either electrons or holes available for conduction. A single semicircular arc corresponding to a single relaxation process was observed for all the investigated ceramics, suggesting a grain contribution to the total resistance in these materials. Arrhenius plots were used to obtain the activation energy for the samples. [ABSTRACT FROM AUTHOR]

In the present study, different mole percent of SiO (~10-20 nm) was dispersed into 85.32[NaNO]-14.68[Sr(NO)] mixed system. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) characterizations were carried out on present dispersed system. Alternate current (AC) and direct current (DC) conductivities, dielectric constant, loss, and impedance measurements have been studied in the frequency range from 1 Hz to 10 MHz and in the temperature range from 297 to 553 K. The XRD, FTIR, SEM, and DSC studies of SiO dispersed systems reveal the formation of amorphous phase. The frequency dependent ac conductivity follows Jonscher's universal power law. Dimensionless frequency exponent ( n) and dispersion parameter ( A) are determined. The enhancement in dc conductivity is observed with the m/o of SiO in these electrolyte systems and attains maximum at 20.55 m/o, where from the enhancement starts falling with further increase in m/o, and this enhancement in conductivity is explained using the formation of amorphous phase of ionic salt. [ABSTRACT FROM AUTHOR]

Effect of Ag addition on the a.c. conductivity as a function of frequency in Se80.5Bi1.5Te18 - yAgy (y 1.0, 1.5 and 2.0 at. %) glassy alloy has been investigated in the temperature range 300-355 K. The electrical conductivity is measured as a function of frequency (ω) of an alternating electric field in the frequency range 1 -500 kHz, using Wayne Kerr 6500 B Impedance Analyzer. A.C. conductivity σ(ω) is found to increases with an increase in frequency for the entire range of temperature in all compositions. The frequency exponent s is found to decrease with an increase in temperature which indicates that the correlated barrier hopping is the possible conduction mechanism in the investigated samples. [ABSTRACT FROM AUTHOR]

Existing experimental data for the temperature dependence of 1/f noise in both n- and p-channel MOS transistors are heuristically compared with either bulk or surface phonon spectra or with both of them. It is found that the noise structure mirrors different van Hove singularities in both bulk and surface phonon spectra. This is thought to be the signature of surface and bulk phonons in the 1/f noise of MOS transistor. For a Debye phonon spectrum, an intriguing 1/τ distribution is obtained. The famous connection between oxide states and 1/f noise can be understood in terms of phonon scattering if the tunneling is inelastic. Striking similarities were found in the temperature dependence of the frequency exponent in different MOS transistors and all of them feature similarities with those of the frequency exponent in silicon on sapphire. This indicates that a common structural factor is controlling the temperature variation in both systems. Starting from the observation that the noise intensity vs. temperature is the image of the phonon density of states, the temperature dependence of the frequency exponent was calculated. It is in a reasonable agreement with the experiments for both n-channel transistors and silicon on sapphire sample. [ABSTRACT FROM AUTHOR]