Terahertz-wave detection using an organic DAST crystal covering ultra-wide frequency-range at room temperature

2009 ◽  
Author(s):  
H. Minamide ◽  
J. Zhang ◽  
R. Guo ◽  
S. Ohno ◽  
K. Miyamoto ◽  
...  
Keyword(s):  
Room Temperature ◽  
Terahertz Wave ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Wave Detection

Investigation of Room Temperature Mössbauer Spectroscopy and Initial Permeability Properties of Al3+ Substituted Cobalt Ferrites

SPIN ◽  
2018 ◽  
Vol 08 (01) ◽  
pp. 1840005
Author(s):  
Rabia Pandit ◽  
Pawanpreet Kaur ◽  
K. K. Sharma ◽  
Mohd. Hashim ◽  
Ravi Kumar
Keyword(s):  
Loss Factor ◽  
Room Temperature ◽  
Magnetic Hyperfine Field ◽  
Initial Permeability ◽  
Wide Frequency Range ◽  
Ion Concentration ◽  
Frequency Range ◽  
High Frequencies ◽  
Relative Loss ◽  
Cobalt Ferrites

In the present work, Al[Formula: see text] substituted cobalt ferrites (CoFe[Formula: see text]AlxO4, [Formula: see text], 0.4, 0.6, 0.8) have been synthesized via standard solid-state reaction technique. The incorporation of Al[Formula: see text] ions in cobalt ferrite has been shown to play an important role in modifying the magnetic properties. The room temperature (300[Formula: see text]K) [Formula: see text]Fe Mössbauer spectra reveals that the studied samples show two characteristic ferromagnetic zeeman sextets at A and B-sites at lower Al[Formula: see text] ion concentration (i.e., up to [Formula: see text]). However, a paramagnetic relaxation has been noted for higher Al[Formula: see text] substitution (for [Formula: see text] and 0.8) samples. The dependence of the Mössbauer parameters such as isomer shift, quadrupole splitting, line width and magnetic hyperfine field on Al[Formula: see text] ion concentration has also been noted. The variations in initial permeability over a wide frequency range (125[Formula: see text]kHz to 30[Formula: see text]MHz) at 300[Formula: see text]K have been recorded. The fairly constant values of initial permeability and the low values of the relative loss factor of the order of 10[Formula: see text] to 10[Formula: see text] over the wide frequency range are the important findings of the present work. The observed low values of relative loss factor at high frequencies suggest that the studied ferrites are promising materials to be used in microwave applications.

scholarly journals Injection pulse-seeded terahertz-wave parametric generator with gain enhancement in wide frequency range

2019 ◽  
Vol 27 (16) ◽  
pp. 22808 ◽  
Author(s):  
Longhuang Tang ◽  
Degang Xu ◽  
Yuye Wang ◽  
Chao Yan ◽  
Yixin He ◽  
...  
Keyword(s):  
Terahertz Wave ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Gain Enhancement ◽  
Parametric Generator ◽  
Injection Pulse

Magnetic Resonance in CuCr2S4 Nanoclusters and Nanocrystals

2015 ◽  
Vol 233-234 ◽  
pp. 542-545
Author(s):  
Anatolii Pankrats ◽  
Alexander Vorotynov ◽  
Vasilii Tugarinov ◽  
Sergey Zharkov ◽  
Galina Abramova ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Room Temperature ◽  
Magnetic Moments ◽  
Resonance Field ◽  
Wide Frequency Range ◽  
Blocking Temperature ◽  
Frequency Range ◽  
Low Field ◽  
Nanocrystalline Particles ◽  
X Band

Nanoclusters and nanocrystals of the room temperature magnetic spinel CuCr2S4 synthesized using a facile solution-based method were examined by magnetic resonance in a wide frequency range 9.6÷80 GHz and at temperatures down to 4.2 K. Decreasing of the resonance field and broadening of the resonance lines are found below ∼ 50 K for both the nanocluster and nanocube samples due to the freezing of magnetic moments of nanocubes and nanocrystalline particles constituting nanoclusters. Additional blocking temperature Tb≅300 K appears in nanoclusters due to the freezing of the magnetic moment of the entire cluster as a whole. Below this temperature, an additional low-field resonance line is found in the resonance spectra of nanoclusters at X-band.

Cu(OH)2: a New Ferroelectric

1995 ◽  
Vol 28 (5) ◽  
pp. 594-598 ◽  
Author(s):  
S. C. Abrahams ◽  
J. Ravez ◽  
A. Simon ◽  
A. Reller ◽  
H. R. Oswald
Keyword(s):  
Crystal Structure ◽  
Heat Capacity ◽  
Ionic Conductivity ◽  
Curie Temperature ◽  
Room Temperature ◽  
Structural Transition ◽  
Wide Frequency Range ◽  
Dielectric Anomaly ◽  
Frequency Range ◽  
Acta Cryst

The crystal structure of Cu(OH)2, recently redetermined at room temperature by Oswald, Reller, Schmalle & Dubler [Acta Cryst. (1990), C46, 2279–2284], is shown to satisfy the structural criteria for ferroelectricity. The Cu2+ ion at 295 K is displaced 0.131 Å from the most likely paraelectric atomic arrangement, allowing the prediction to be made that the ferroelectric Curie temperature is Tc = 343 K. This prediction is in excellent agreement with an earlier report of a reversible structural transition at 325–335 K in Cu(OH)2. The presence of a λ-shaped anomaly in the heat capacity at about 335 K has been confirmed, and a dielectric anomaly is also observed at similar temperatures over a wide frequency range; the frequency dependence is dispersive, owing at least partly to ionic conductivity. The prediction is hence verified, and Cu(OH)2 is demonstrated experimentally to be a new ferroelectric.

scholarly journals Lattice strain driven dielectric insulation response of Sr1−xCaxBi2Nb2O9 ceramics

2016 ◽  
Vol 06 (03) ◽  
pp. 1650021
Author(s):  
Vaibhav Shrivastava
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Frequency ◽  
Room Temperature ◽  
Lattice Strain ◽  
Calcium Content ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Dielectric Insulation ◽  
Room Temperature Dielectric Constant

In this paper, effects of lattice strain on dielectric properties of Sr[Formula: see text]CaxBi2Nb2O9 ([Formula: see text]–0.5 in steps of 0.1) ceramics are reported. High frequency dipolar polarization is observed to increase for 10% calcium addition and suppresses thereafter on higher calcium concentrations. The dielectric loss values for all doped samples were lower compared to undoped one at frequencies beyond 1[Formula: see text]kHz. The sample with [Formula: see text] shows room temperature dielectric constant in the range (130[Formula: see text][Formula: see text][Formula: see text]12) over a wide frequency range from 50[Formula: see text]Hz to 1[Formula: see text]MHz also minimum dielectric loss among all other sample for the same frequency range. Remarkable increase in Curie temperature ([Formula: see text]) by 50[Formula: see text]C is recorded in the present work by increasing 10% calcium content in SBN compostion. All higher doped samples indicate increase in [Formula: see text] by further higher amount. In addition, dc conductivity of all samples is measured for all samples and increase in calcium content is observed to generate more insulating compositions compared to undoped SBN with higher intrinsic activation energies.

Structural and dielectric studies of lead-free ceramics: Na1/2Y1/2TiO3

Open Physics ◽  
2008 ◽  
Vol 6 (4) ◽  
Author(s):  
Subrat Barik ◽  
Ram Choudhary ◽  
Prasanta Mahapatra
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Microstructural Analysis ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Polaron Hopping ◽  
X Ray ◽  
Lead Free Ceramics ◽  
Phase Compound ◽  
Different Temperatures

AbstractThe polycrystalline samples of Na1/2Y1/2TiO3 were prepared by the mixed-oxide method. A preliminary X-ray structural analysis was shown to exhibit the formation of a single-phase compound with an orthorhombic structure. Microstructural analysis by scanning electron microscopy (SEM) exhibits well defined grains distributed uniformly through out the sample suggesting the compactness and homogeneity of the sample. Detailed studies of dielectric properties of Na1/2Y1/2TiO3 in a wide frequency range (102–106 Hz) at different temperatures (31–500°C) show a dielectric anomaly at 105°C, which may be related to a ferroelectricparaelectric phase transition as suggested by hysteresis loop at room temperature. An ac conductivity (σ ac) of the material is mainly governed by the polaron hopping mechanism, which is also influenced by both frequency and temperature. The activation energy was obtained from the plot of temperature with a.c. conductivity.

scholarly journals Photothermal, Photoelectric, and Photothermoelectric Effects in Bi-Sb Thin Films in the Terahertz Frequency Range at Room Temperature

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 76
Author(s):  
Mikhail K. Khodzitsky ◽  
Petr S. Demchenko ◽  
Dmitry V. Zykov ◽  
Anton D. Zaitsev ◽  
Elena S. Makarova ◽  
...  
Keyword(s):  
Thin Films ◽  
Terahertz Radiation ◽  
Room Temperature ◽  
Voltage Drop ◽  
Radiation Detection ◽  
Radiation Detectors ◽  
Thz Radiation ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range

The terahertz frequency range is promising for solving various practically important problems. However, for the terahertz technology development, there is still a problem with the lack of affordable and effective terahertz devices. One of the main tasks is to search for new materials with high sensitivity to terahertz radiation at room temperature. Bi1−xSbx thin films with various Sb concentrations seem to be suitable for such conditions. In this paper, the terahertz radiation influence onto the properties of thermoelectric Bi1−xSbx 200 nm films was investigated for the first time. The films were obtained by means of thermal evaporation in vacuum. They were affected by terahertz radiation at the frequency of 0.14 terahertz (THz) in the presence of thermal gradient, electric field or without these influences. The temporal dependencies of photoconductivity, temperature difference and voltage drop were measured. The obtained data demonstrate the possibility for practical use of Bi1−xSbx thin films for THz radiation detection. The results of our work promote the usage of these thermoelectric materials, as well as THz radiation detectors based on them, in various areas of modern THz photonics.

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