Effect of Pressure on the Static Dielectric Constant of KTa<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Abel, W. R.

doi:10.1103/physrevb.4.2696

Cited by 57 publications

(12 citation statements)

References 12 publications

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“…The KTaO 3 insert was assumed to have a relative dielectric constant r = 261 and loss tangent tan ␦ = 7.5ϫ 10 −4 at room temperature. 3,16,17 The dielectric length was varied over the range 1 mmϽ l d Ͻ 3 mm, giving an isolated natural resonance frequency of 9.4947 GHz at 1.75 mm. At this diameter, the isolated dielectric resonator efficiency parameter ⌳ d = 41.01 G / W 1/2 .…”

Section: Resultsmentioning

confidence: 99%

Dielectric microwave resonators in TE011 cavities for electron paramagnetic resonance spectroscopy

Mett

Sidabras

Головина

et al. 2008

Review of Scientific Instruments

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The coupled system of the microwave cylindrical TE 011 cavity and the TE 01␦ dielectric modes has been analyzed in order to determine the maximum achievable resonator efficiency parameter of a dielectric inserted into a cavity, and whether this value can exceed that of a dedicated TE 01␦ mode dielectric resonator. The frequency, Q value, and resonator efficiency parameter ⌳ for each mode of the coupled system were calculated as the size of the dielectric was varied. Other output parameters include the relative field magnitudes and phases. Two modes are found: one with fields in the dielectric parallel to the fields in the cavity center and the other with antiparallel fields. Results closely match those from a computer program that solves Maxwell's equations by finite element methods. Depending on the relative natural resonance frequencies of the cavity and dielectric, one mode has a higher Q value and correspondingly lower ⌳ than the other. The mode with the higher Q value is preferentially excited by a coupling iris or loop in or near the cavity wall. However, depending on the frequency separation between modes, either can be excited in this way. A relatively narrow optimum is found for the size of the insert that produces maximum signal for both modes simultaneously. It occurs when the self-resonance frequencies of the two resonators are nearly equal. The maximum signal is almost the same as that of the dedicated TE 01␦ mode dielectric resonator alone, ⌳ Х 40 G / W 1/2 at X-band for a KTaO 3 crystal. The cavity is analogous to the second stage of a two-stage coupler. In general, there is no electron paramagnetic resonance ͑EPR͒ signal benefit by use of a second stage. However, there is a benefit of convenience. A properly designed sample-mounted resonator inserted into a cavity can give EPR signals as large as what one would expect from the dielectric resonator alone.

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Section: Resultsmentioning

confidence: 99%

Dielectric microwave resonators in TE011 cavities for electron paramagnetic resonance spectroscopy

Mett

Sidabras

Головина

et al. 2008

Review of Scientific Instruments

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“…Although several frequency-dependent peaks are seen in the dielectric loss ( Fig.24(b)), it can be reasonably attributed to polarization relaxations due to defects (Soon et al, 2010). Interestingly, within the low-temperature region, the dielectric behavior follows the Barrett's relation (Barrett, 1952) that is characteristic for the quantum paraelectric system (Abel, 1971;Höchli & Boatner,1979;Itoh et al, 1999), suggesting that AgTaO 3 may be a quantum paraelectric. On the other hand, two step-like dielectric anomalies corresponding to the phase transitions from monoclinic to tetragonal and tetragonal to cubic were observed at 694 and 780 K, respectively, upon heating the samples (Fig.26).…”

Section: Phase Formation and Dielectric Behaviorsmentioning

confidence: 92%

Ferroelectricity in Silver Perovskite Oxides

Fu¹,

Itoh²

2011

Ferroelectrics - Material Aspects

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“…Many studies have been reported on the quantum paraelectricity of the perovskite substances [2][3][4][5][6][7][8]. However, the study on the dynamics of the quantum fluctuation has been very few because of the difficulty of the experiment to detect the dynamical properties in the low temperature.…”

Section: Soft-mode In Quantum Paraelectric Srtio 3 [393]/169mentioning

confidence: 99%

“…In the case of STO the quantum fluctuation overcomes with the ordering force instead of the reduced thermal fluctuation in the low temperature. The ferroelectric order is suppressed and the crystal keeps the paraelectric state down to 0 K. Thus STO and other related substances are the incipient ferroelectrics [2][3][4][5].…”

Section: Introductionmentioning

confidence: 98%

Soft-mode Dynamics in the Ferroelectric Phase Transition of Quantum Paraelectric SrTiO₃

et al. 2009

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The light scattering spectra of the lowest frequency polar mode in the oxygen-isotope induced ferroelectric SrTi 18 O 3 were observed in both paraelectric and ferroelectric phases. A perfect softening of the E u mode at the phase transition is observed by the highresolution spectroscopy in terms of the Fabry-Perot interferometry. The Raman-inactive polar modes are activated by the local symmetry breaking in the centrosymmetric tetragonal-paraelectric phase. The phase transition mechanism is a perfect displacive type in agreement with the theoretical studies. Both of the perfect softening and the dynamic inhomogeneity enhanced near the critical concentration play an essential role in the oxygen-isotope induced phase transition of SrTi 18 O 3 .

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Effect of Pressure on the Static Dielectric Constant of KTaO3

Cited by 57 publications

References 12 publications

Dielectric microwave resonators in TE011 cavities for electron paramagnetic resonance spectroscopy

Dielectric microwave resonators in TE011 cavities for electron paramagnetic resonance spectroscopy

Ferroelectricity in Silver Perovskite Oxides

Soft-mode Dynamics in the Ferroelectric Phase Transition of Quantum Paraelectric SrTiO₃

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Effect of Pressure on the Static Dielectric Constant of KTaO3

Cited by 57 publications

References 12 publications

Dielectric microwave resonators in TE011 cavities for electron paramagnetic resonance spectroscopy

Dielectric microwave resonators in TE011 cavities for electron paramagnetic resonance spectroscopy

Ferroelectricity in Silver Perovskite Oxides

Soft-mode Dynamics in the Ferroelectric Phase Transition of Quantum Paraelectric SrTiO3

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Soft-mode Dynamics in the Ferroelectric Phase Transition of Quantum Paraelectric SrTiO₃