Simultaneous measurements of specific heat capacity and dielectric constant of ferroelectric Ba1-xSrxTiO3

Sawai, Shinya; Tanaka, Hirokazu; Morimoto, K.; Hisano, K.; Yamamoto, Takashi

doi:10.1080/00150190008228403

Cited by 6 publications

(4 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where c is heat capacity, which should vary with boundary conditions and polarization configurations [41], and depend on the temperature [42][43][44][45] (figure S2). What's more, the effective heat capacity relies on the volume fraction of two materials in the superlattice.…”

Section: The Emergence Of Negative Electrocaloric Effectmentioning

confidence: 99%

The emergence of tunable negative electrocaloric effect in ferroelectric/paraelectric superlattices

Ji¹,

Chen²,

Zheng³

2020

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

The electrocaloric effect in ferroelectrics provides a promising solid-state refrigeration technology to meet the urgent demand for heat management in the integrated circuits. Usually, ferroelectrics show a positive electrocaloric effect, i.e. the application of an electric field causes an increase in temperature. In contrast, the negative electrocaloric effect is also possible but much less explored. These two effects, if occur in the same system, could be combined to improve the cooling performance. Here we report the occurrence of both positive and negative electrocaloric effects in ferroelectric/paraelectric PbTiO3/SrTiO3 superlattice based on phase-field simulations. The superlattice is found to stabilize a variety of vortex dipole states (with the different number of vortex) when the PbTiO3 and SrTiO3 layers have suitable thicknesses. The unique response of these topological states to the external electric field gives rise to both positive and negative electrocaloric effect, and the latter is associated with the field-dependent vortex-to-polar state transformation. The multiplicity of the vortex dipole states brings tuning freedom for the optimization of electrocaloric properties. Moreover, the electrocaloric effect is also sensitive to the strength of the screening effect determined by the thickness of the SrTiO3 layer. We thus demonstrate a novel mechanism of negative electrocaloric effect in ferroelectrics with topological dipole states and indicates the screening effect as an effective way to engineer the electrocaloric performance.

show abstract

Section: The Emergence Of Negative Electrocaloric Effectmentioning

confidence: 99%

The emergence of tunable negative electrocaloric effect in ferroelectric/paraelectric superlattices

Ji¹,

Chen²,

Zheng³

2020

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…Ab initio calculations determined the interaction parameter of the cubic phase of the Sr x Ba 1‐ x TiO 3 solid solution to be 7.2 kJ/mol . Calorimetric measurements had been performed on several compositions in this system …”

Section: Introductionmentioning

confidence: 99%

“…47 Calorimetric measurements had been performed on several compositions in this system. 48 The (Ca,Ba)TiO 3 system shows a wide region of insolubility. [49][50][51] DeVries and Roy suggested a phase diagram with maximum miscibility of %30 wt% in each end member at 1868 K, which rapidly decreases at lower temperature.…”

Section: Introductionmentioning

confidence: 99%

Thermochemistry of (Ca_xSr_1‐x)TiO₃, (Ba_xSr_1‐x)TiO₃, and (Ba_xCa_1‐x)TiO₃ Perovskite Solid Solutions

et al. 2012

View full text Add to dashboard Cite

High‐temperature solution calorimetry in molten 3Na2O•4MoO3 solvent at 975 K is used to measure the enthalpy of mixing of (CaxSr1‐x)TiO3 and (BaxSr1‐x)TiO3 solid solutions. Both solid solutions show positive enthalpy of mixing, however, the (BaxSr1‐x)TiO3 shows less deviation from ideality, with interaction parameter λ = 8.5 ± 3.8 kJ/mol, than (CaxSr1‐x)TiO3 with interaction parameter λ = 25.3 ± 2.0 kJ/mol. The smaller interaction parameter of the (BaxSr1‐x)TiO3 system is attributed to the volume mismatch of the end‐members. The larger interaction parameter of (CaxSr1‐x)TiO3 may be related to larger ionic radius difference of Ca and Sr and may also reflect the additional energy needed to overcome the lattice distortion of the orthorhombic CaTiO3 to incorporate it into the cubic perovskite SrTiO3. (BaxCa1‐x)TiO3 has a large positive heat of mixing and limited solid solubility as derived from its phase diagram. This study indicates the tendency of SrTiO3 and BaTiO3 to separate from a CaTiO3 host matrix, which may be significant in perovskite‐bearing nuclear waste ceramics incorporating 90Sr and 137Ba.

show abstract

“…(∂P /∂T ) E was obtained from the sixth-order polynomial fits to the P vs. T data at a fixed electric field (E), which were extracted from the P -E hysteresis loops. The specific heat C E = 500 J/K·kg was assumed to remain almost constant in the measured temperature range [16] and the mass density ρ = 5.783 g/cm 3 was used in the calculation [17]. Figure 3 displays the electrocaloric temperature changes ΔT in the BSTO thin film as obtained by using Eq.…”

Section: Resultsmentioning

confidence: 99%

Increased saturation field as the origin of the giant electrocaloric effect in Ba0.8Sr0.2TiO3 thin films

Park

Sung

Jung

et al. 2015

Journal of the Korean Physical Society

View full text Add to dashboard Cite

We investigated the electrocaloric (EC) effects in epitaxial Ba0.8Sr0.2TiO3 (BSTO) thin films grown on LaAlO3 and MgO substrates and in BSTO sol-gel thin films grown on Si substrates. We compared the EC effects in two forms of BSTO to confirm whether the giant EC effect recently observed in the polycrystalline thin film is an intrinsic effect or an extrinsic effect exclusively occurring in polycrystalline thin films with nano-sized grains. The EC effect in our BSTO single crystals exhibited a moderate EC temperature change over a broad temperature range. On the other hand, the EC effect in the BSTO sol-gel film was observed over a narrow temperature range with a giant ΔT of about 14 • C. We claim that this giant EC effect is due to the increased saturation field related to the small grain size in the sol-gel thin film.

show abstract

Simultaneous measurements of specific heat capacity and dielectric constant of ferroelectric Ba_1-xSr_xTiO₃

Cited by 6 publications

References 6 publications

The emergence of tunable negative electrocaloric effect in ferroelectric/paraelectric superlattices

The emergence of tunable negative electrocaloric effect in ferroelectric/paraelectric superlattices

Thermochemistry of (Ca_xSr_1‐x)TiO₃, (Ba_xSr_1‐x)TiO₃, and (Ba_xCa_1‐x)TiO₃ Perovskite Solid Solutions

Increased saturation field as the origin of the giant electrocaloric effect in Ba0.8Sr0.2TiO3 thin films

Contact Info

Product

Resources

About

Simultaneous measurements of specific heat capacity and dielectric constant of ferroelectric Ba1-xSrxTiO3

Cited by 6 publications

References 6 publications

The emergence of tunable negative electrocaloric effect in ferroelectric/paraelectric superlattices

The emergence of tunable negative electrocaloric effect in ferroelectric/paraelectric superlattices

Thermochemistry of (CaxSr1‐x)TiO3, (BaxSr1‐x)TiO3, and (BaxCa1‐x)TiO3 Perovskite Solid Solutions

Increased saturation field as the origin of the giant electrocaloric effect in Ba0.8Sr0.2TiO3 thin films

Contact Info

Product

Resources

About

Simultaneous measurements of specific heat capacity and dielectric constant of ferroelectric Ba_1-xSr_xTiO₃

Thermochemistry of (Ca_xSr_1‐x)TiO₃, (Ba_xSr_1‐x)TiO₃, and (Ba_xCa_1‐x)TiO₃ Perovskite Solid Solutions