Thermal conductivity of K1−xLixTaO3 and KTa1−xNbxO3

Tachibana, Makoto

doi:10.1016/j.ssc.2015.08.014

Cited by 5 publications

(7 citation statements)

References 29 publications

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“…The dependence of these thermal conductivity values on temperature is, however, quite different. The thermal conductivity of pristine BaSnO 3 increases as temperature decreases to 20 K, whereas the thermal conductivities of SrTiO 3 and KTaO 3 reach a maximum value at temperatures between 50 and 100 K. , For the cation-doped BaSnO 3 and vacancy-doped BaSnO 3 , the temperature dependence of thermal conductivity remains similar to that of the pristine BaSnO 3 in the studied range from 20 to 500 K, suggesting the minor role of defect scattering in the thermal transport in BaSnO 3 compared with the major role of inherent phonon–phonon scattering …”

Section: Results and Discussionmentioning

confidence: 71%

“…We compare the first-principles predictions of heat capacity and thermal conductivity with the experimental data available in the literature, , which show reasonable agreement. We further quantify different impacts of scattering due to point defects by comparing the thermal properties of BaSnO 3 with other perovskites. − This work will thus constitute a comprehensive study on the thermal conductivity of BaSnO 3 as well as the impact of impurities and oxygen vacancies, which is important for developing advanced TCO materials with desirable thermal properties.…”

Section: Introductionmentioning

confidence: 99%

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Roles of Point Defects in Thermal Transport in Perovskite Barium Stannate

et al. 2018

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Perovskite barium stannate (BaSnO3) is a promising candidate that can be used as transparent conducting oxide in optoelectronic devices and as the channel material in high-mobility oxide electronics. In this work, we calculate the lattice thermal conductivity and investigate the impact of point defects on thermal transport in BaSnO3 based on the phonon Boltzmann transport equations with interatomic force constants from first-principles calculations. In pristine BaSnO3, we find the contribution of acoustic phonons to thermal transport accounts for 54% at 300 K and the rest is attributed to the lower-frequency (27.5–50 THz) optical modes with relatively high group velocity. We show oxygen vacancies and impurities can cause noticeable reduction in thermal conductivity of BaSnO3, but the corresponding mechanisms differ in terms of scattering rates on different phonon modes. The thermal conductivity reduction due to oxygen vacancies at 300 K is mainly caused by the increased scattering of the acoustic phonons and the low-frequency optical phonons. Lanthanum and potassium impurities mainly increase the scattering of acoustic phonons, but antimony impurity lowers the thermal conductivity by increasing the scattering rate of dominant phonons, including both the acoustic modes and the low-frequency optical modes. The results and findings facilitate us to better understand the thermal transport mechanisms of perovskite oxides with an emphasis on the impact of oxygen vacancies and impurities on the thermal properties of BaSnO3.

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Section: Results and Discussionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Roles of Point Defects in Thermal Transport in Perovskite Barium Stannate

et al. 2018

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“…54 In fact, in the highest frequency range, all the curves merge and become independent of frequency, suggesting a possibility of space charge release. 53…”

Section: Resultsmentioning

confidence: 99%

“…This behavior could be explained by the presence of space charges and/or ionic conduction. [50][51][52][53] At high and medium frequencies, Z ′ is independent of temperature, which reduces the inuence of space charges. 54 In fact, in the highest frequency range, all the curves merge and become independent of frequency, suggesting a possibility of space charge release.…”

Section: Impedance Analysismentioning

confidence: 99%

AC conductivity and phase transition of the BST–BFO ceramic doped with Yb

et al. 2022

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“…The ferroelectric transition temperature T c of KTN is known to be tuned by Nb-doping to the Ta site [55]. Single crystals of KTN with nominal x = 0.02 were prepared by the flux methods [56]. To characterize our KTN samples, we measured the temperature dependence of capacitance at zero magnetic field using the Andeen-Hagerling (AH) 2500A automatic bridge with a measuring frequency of 1 kHz and GR 1615A with 50 kHz.…”

Section: B Temperature Measurement Of Capacitance Thermometer In Puls...mentioning

confidence: 99%

Capacitive detection of magnetostriction, dielectric constant, and magneto-caloric effects in pulsed magnetic fields

Miyake,

Mitamura,

Kawachi

et al. 2020

Preprint

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We report on the development of a capacitance measuring system which allows measurements of capacitance in pulsed magnetic fields up to 61 T. By using this system, magnetic-field responses of various physical quantities such magnetostriction, magnetic-field-induced change in complex dielectric constant, and magneto-caloric effect can be investigated in pulsed-magnetic-field conditions. Here, we examine the validity of our system for investigations of these magnetic-field-induced phenomena in pulse magnets. For the magnetostriction measurement, magnetostriction of a specimen can be measured through a change in the capacitance between two aligned electrodes glued on the specimen and a dilatometer. We demonstrate a precise detection of valley polarization in semimetallic bismuth through a magnetostriction signal with a resolution better than 10 −6 of the relative length change. For the magnetic-field-induced change in complex dielectric constant, we successfully observed clear dielectric anomalies accompanied by magnetic/magnetoelectric phase transitions in multiferroic Pb(TiO)Cu 4 (PO 4 ) 4 . For the measurement of magneto-caloric effect, a magnetic-field-induced change in sample temperature was verified for Gd 3 Ga 5 O 12 with a capacitance thermometer made of a non-magnetic ferroelectric compound KTa 1−x Nb x O 3 (x = 0.02) whose capacitance is nearly field-independent. These results show that our capacitance measuring system is a promising tool to study various magnetic-field-induced phenomena which have been difficult to detect in pulsed magnetic fields.

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Thermal conductivity of K1−xLixTaO3 and KTa1−xNbxO3

Cited by 5 publications

References 29 publications

Roles of Point Defects in Thermal Transport in Perovskite Barium Stannate

Roles of Point Defects in Thermal Transport in Perovskite Barium Stannate

AC conductivity and phase transition of the BST–BFO ceramic doped with Yb

Capacitive detection of magnetostriction, dielectric constant, and magneto-caloric effects in pulsed magnetic fields

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