Article
Chemistry, Multidisciplinary
Ruowei Yin, Junjie Li, Xiaopo Su, Shiqiang Qin, Chengye Yu, Yuxuan Hou, Chuanbao Liu, Yanjing Su, Lijie Qiao, Turab Lookman, Yang Bai
Summary: A multilayer ferroelectric structure with interlayer synergistic phase transitions is proposed to enhance the electrocaloric effect in ferroelectric materials, resulting in improved cooling performance for practical refrigeration applications.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Physics, Applied
A. P. Moina
Summary: Using a previously developed model, the study explores the electrocaloric effect (ECE) in antiferroelectric crystals of squaric acid, which undergoes a two-stage process with an intermediate ferrielectric phase during low-temperature polarization reorientation induced by an external electric field. The T-E landscape of the model entropy is analyzed. The ECE is found to be negative in the antiferroelectric phase, positive at low fields in the ferrielectric phase, and positive at all temperatures and fields in the ferroelectric phase. A negative EC temperature shift ΔT of approximately -2.7 K at 200 kV/cm is predicted. The supercritical behavior of the Gruneisen parameter in the crossover region between two bicritical end points is also studied.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Energy & Fuels
Junning Li, Alvar Torello, Youri Nouchokgwe, Torsten Granzow, Veronika Kovacova, Sakyo Hirose, Emmanuel Defay
Summary: Electrocaloric (EC) materials offer a promising alternative to traditional caloric heat pumps, as they can achieve significant temperature changes under the application of electric fields. Researchers have found EC effect in lead-free BaTiO3 multilayer capacitors, which exhibit strong first-order phase transition and improved electrical resistivity by adding a dopant. These findings suggest the potential for designing lead-free caloric cooling prototypes using optimized BaTiO3 capacitors.
JOURNAL OF PHYSICS-ENERGY
(2023)
Article
Chemistry, Physical
Magdalena Krupska-Klimczak, Irena Jankowska-Sumara, Przemyslaw Gwizd, Marceli Koralewski, Andrzej Soszynski
Summary: In this study, the ferroelectric properties of Pb5Ge3O11 single crystals modified by Ba ions were investigated. The measurements showed that Ba doping significantly affected all the measured parameters, resulting in the lowering of Curie temperature, gradual diffusion of phase transition, and decrease in polarization values and coercive field. The overall electrocaloric effect (ECE) decreased due to the reduction in polarization. However, the expanded range of phase transition occurrence (up to 30 K) could be beneficial for applications.
Article
Materials Science, Ceramics
Qihan Peng, Kumara Raja Kandula, Zhongqiu Xia, Chao Zhang, Yujing Zhang, Ying Yang, Qingfeng Zhang, Shenglin Jiang, Jiwen Xu, Guangzu Zhang
Summary: In this study, the Zr/Ti molar ratio was tailored to alter and optimize the structural properties and ECE response in polycrystalline ceramics. Multiple phase transition behaviors were observed, with significant improvements in ECE adiabatic temperature change and electrocaloric strength noted in certain compositions, making them promising candidates for next generation solid-state refrigeration technology.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
M. V. Gorev, V. S. Bondarev, I. N. Flerov, K. Bormanis, E. Birks
Summary: Using the Landay thermodynamic potential, the T-E phase diagrams and electrocaloric effect in solid solutions (1-x)Pb(Ni1/3Nb2/3)O-3-xPbTiO3 (PNN-PT) were studied. The composition, temperature range, and electric field parameters significantly influenced the phase transitions, stability of crystalline phases, and electrocaloric properties. The intensive electrocaloric effect of the 0.8PNN-0.2PT compound indicates its potential as a solid-state refrigerant.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Physics, Applied
Jyotirekha Mallick, Anant Shukla, Shantanu Kumar Panda, Murli Kumar Manglam, Sambit Kumar Biswal, Lagen Kumar Pradhan, Manoranjan Kar
Summary: The electrocaloric effect of lead-free Ba(0.8-x)Sr(0.2)SmxTiO(3) (x = 0.01-0.05) ceramics has been investigated, and it is found that adding Sm3+ can enhance the electrocaloric effect parameter and improve the temperature stability in a broad temperature window.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Ceramics
Nikola Novak, Florian Weyland, George A. Rossetti
Summary: The study found that the electrocaloric effect of Ba(ZrxTi1-x)O-3 (BZT) decreases significantly with increasing Zr concentration, but an enhanced electrocaloric responsivity occurs at the triple point composition.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Ceramics
Nikola Novak, Florian Weyland, Nasser Khakpash, George A. Rossetti Jr
Summary: The composition-temperature-electric field diagram and electrocaloric properties of BaTi1_xZrxO3 (BZT) were calculated. The adiabatic temperature change due to material polarization at critical end, tricritical, and phase convergence points was quantified. The largest temperature change occurred at the first-order paraelectric to ferroelectric transitions, while the greatest material polarization contribution was observed at the critical temperature. The maximum electrocaloric responsivity occurred at a field 1.25 times greater than the critical field. The enhanced temperature change near the convergence point was attributed to greater polarization change in the rhombohedral phase and a polar glasslike state that contributed to the dipolar configurational entropy.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Ceramics
Qiumei Wei, Lovro Fulanovic, Kodumudi Venkataraman Lalitha, Mupeng Zheng, Yudong Hou, Mankang Zhu, Linjing Liu, Yunfei Chang, Rui Xue
Summary: Innovative cooling technologies are crucial for system design in many industries. This study explores the use of lead-free (Na1/2Bi1/2)(0.80)Sr-0.20(Zn1/3Nb2/3)(x)Ti1-xO3 ceramics, which exhibit a large electrocaloric effect (ECE) and an extended working temperature range. The excellent ECE performance is attributed to the evolution of polar nanoregions. This material shows promise for solid-state refrigeration systems with a broad range of operating temperatures.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Engineering, Multidisciplinary
FeiHong Du, ZhiWu Song, YuTao Xu, DongLin Han, Qiang Li, ShanYu Zheng, JiaHe Shen, XiaoShi Qian
Summary: Multi-element B-site substituted BaTiO3 ceramics exhibit an enhanced electrocaloric effect and refrigeration capacity, with an operating temperature window covering room temperature for practical use. The multi-element substitution improves the overall electrocaloric effect performance, allowing for a high degree of polar reorientation and utilization of large polar entropy by the external electric field.
SCIENCE CHINA-TECHNOLOGICAL SCIENCES
(2023)
Article
Crystallography
Ojars Martins Eberlins, Eriks Birks, Maija Antonova, Maris Kundzins, Maris Livins, Andris Sternberg
Summary: Promising results were obtained in studies of the electrocaloric effect in thin films recently. Therefore, studying this effect in bulk ferroelectrics at high applied electric field values has become an important task in the search for suitable materials for cooling devices based on the electrocaloric effect. This study investigated the electrocaloric effect in (1-x)(0.8Na(1/2)Bi(1/2)TiO(3)-0.2BaTiO(3))-xCaTiO(3) solid solutions using the direct method, with electric fields ranging from 0 to 100 kV/cm and temperatures up to 150 degrees C. The choice of starting composition was motivated by the high spontaneous polarization within the studied electric field range, and the addition of CaTiO3 helped reduce the depolarization temperature. The study found that the highest electrocaloric effect with a temperature change of Delta T = 1.0 degrees C was achieved in the composition with x = 0.050 at 100 degrees C, with a significant contribution from the entropy jump during the first-order phase transition induced by an electric field. The achievable Delta T decreased with increasing CaTiO3 concentration. Simultaneous measurements of polarization current and Delta T allowed for a comparison between the direct and indirect methods of measuring temperature change.
Article
Materials Science, Multidisciplinary
Wenyue Zhao, Ze Li, Zhao Wang, Yazhou Peng, Lei Shi, Wenjing Hua, Jie Wang, Lidong Wang, Wei-Dong Fei, Yu Zhao
Summary: In this study, large and regulable electrocaloric effects at room temperature are achieved in PbZrO3/Ca3Mn2O7 bilayer films based on PbZrO3 phase transition, and the sign of adiabatic temperature change, ΔT, is determined by Ca3Mn2O7 thickness. The formed PbZrO3-Ca3Mn2O7 heterojunction reduces the carrier concentration of the film and establishes a built-in electric field, greatly enhancing the withstanding voltage of the bilayer films. A maximum positive ΔT of 66.5 K is obtained in the bilayer film with a thin Ca3Mn2O7 layer, while a negative ΔT of -9.9 K is obtained with a thick Ca3Mn2O7 layer, both near room temperature. This work presents a simple and effective approach to designing huge electrocaloric effects based on antiferroelectric-containing multilayers near room temperature.
Article
Polymer Science
Vadim Sultanov, Vadim V. Atrazhev, Dmitry Dmitriev, Nikolay S. Erikhman, David U. Furrer, Sergei F. Burlatsky
Summary: The molecular mechanism of the large electrocaloric effect in ferroelectric vinylidene difluoride-based polymers was proposed, involving a phase transition between the ferroelectric beta-phase and condis phase with higher entropy. Molecular dynamics simulations on different copolymers and terpolymers confirmed the mechanism by predicting similar temperature drops.
Article
Materials Science, Ceramics
E. Yu. Koroleva, Yu. N. Sotskova, A. Yu. Molokov, A. F. Vakulenko, Nan Zhang, Fei Li, S. B. Vakhrushev
Summary: The problem of field induced phase transition into the ferroelectric phase in relaxor ceramics, specifically PMN ceramics, has been a topic of study for many years with controversial results. The experiments showed transitions from the glass-like phase to the ferroelectric phase, and a shift in the loss maximum frequency under applied electric field. Unlike single crystals, no clear evidence of phase transition from the paraelectric to the ferroelectric state was found in polycrystalline ceramics.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Marija Dunce, Eriks Birks, Maija Antonova, Reinis Ignatans, Edgars Nitiss, Maris Kundzinsh, Jurgis Grube, Anatolijs Sarakovskis, Andris Sternberg
Article
Materials Science, Multidisciplinary
M. Dunce, A. Olsauskaite, E. Birks, S. Svirskas, A. Kezionis, L. Bikshe, A. Sternberg, J. Banys
Article
Physics, Applied
M. Dunce, G. Krieke, E. Birks, L. Bikse, M. Antonova, A. Sarakovskis
JOURNAL OF APPLIED PHYSICS
(2020)
Article
Chemistry, Physical
Marija Dunce, Eriks Birks, Maija Antonova, Liga Bikse, Sanija Dutkevica, Otto Freimanis, Maris Livins, Laura Eglite, Krisjanis Smits, Andris Sternberg
Summary: This study provides a comprehensive analysis of the microstructure and chemical composition of NBT ceramics at different sintering temperatures, revealing that with increasing sintering temperature, the grain size distribution becomes more diffuse and the average grain size increases, with two types of pores observed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Ceramics
Marija Dunce, Eriks Birks, Maija Antonova, Liga Bikse, Karlis Kundzins, Otto Freimanis, Maris Livins, Sanija Dutkevica, Andris Sternberg
Summary: This study investigates the effect of excess Bi on Na0.5Bi0.5TiO3 ceramics and finds that it reduces the grain size and alters the grain size distribution, with a stronger influence when added before calcination. Excess Bi helps prevent the formation of Bi-deficient inclusions, but high concentrations lead to the formation of Bi-rich inclusions. The study also suggests the presence of another Na-rich phase that is not detectable by X-ray diffraction or energy-dispersive X-ray analysis.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Nanoscience & Nanotechnology
M. Jurjans, L. Bikse, E. Birks, S. Svirskas, M. Antonova, M. Kundzins, A. Sternberg
Summary: This study investigates the structural, electromechanical, and dielectric properties of (1 - x)(0.8Na(0.5)Bi(0.5)TiO(3)-0.2BaTiO(3))-xCaTiO(3) [(1 - x) (0.8NBT-0.2BT)-xCT] ceramics as potential room temperature actuators with high field-induced strain. The choice of 0.8NBT-0.2BT as a starting composition allows for a high tetragonality even far from the morphotropic phase boundary. The addition of CaTiO3 as a third component decreases the depolarization temperature and enables a high field-induced strain at room temperature. The measured strains at the field-induced phase transition are lower than expected, suggesting an incomplete transition from the ferroelectric phase to the nonpolar phase. Among the manufactured samples, a composition with x = 0.100 shows a phase transition close to room temperature and achieves unipolar strains up to 0.23% at E = 65 kV/cm. Electrostrictive-like strain is observed not only above the depolarization temperature but also in the field-induced phase transition region.
Article
Physics, Applied
Marija Dunce, Eriks Birks, Liga Bikse, Reinis Ignatans, Armin Fuith, Heinz Kabelka, Edgars Nitiss, Maris Kundzins, Andris Sternberg
Summary: In this study, the structure and properties of Na0.5Bi0.5TiO3 and 0.95Na(0.5)Bi(0.5)TiO(3)-0.05CaTiO(3) solid solutions were investigated. Differences in thermal expansion and Young's modulus were observed between the two compositions, indicating variations in phase transitions. The temperature dependence of dielectric permittivity was also analyzed, leading to a reconsideration of the underlying mechanism.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Ceramics
M. Dunce, E. Birks, M. Antonova, L. Bikse, M. Livins, A. Sternberg
Summary: The objective of this research is to study how the concentration of A-site vacancies may be increased by forming solid solutions with Sr0.7Bi0.2TiO3. A thorough study of heterogeneity and chemical composition of (1-y)Na0.5Bi0.5TiO3-ySr0.7Bi0.2TiO3 ceramics on a local level is conducted and accompanied by impedance measurements. The chemical composition of the matrix grains remains stable, allowing the formation of A-site vacancies in a wide concentration range.
CERAMICS INTERNATIONAL
(2023)
