Electrocaloric properties of lead-free ferroelectric ceramic near room temperature

2021 ◽  
Vol 127 (6) ◽  
Author(s):  
Hend Kacem ◽  
Ah. Dhahri ◽  
Mohamed Amara Gdaiem ◽  
Z. Sassi ◽  
L. Seveyrat ◽  
...  
Keyword(s):  
Room Temperature ◽  
Ferroelectric Ceramic ◽  
Lead Free

Evaluating the polymorphic phase transition in calcium-doped Ba(Zr0.05Ti0.95)O3: a lead-free piezoelectric ceramic

2013 ◽  
Vol 46 (2) ◽  
pp. 324-331 ◽  
Author(s):  
Gurvinderjit Singh ◽  
V. S. Tiwari ◽  
P. K. Gupta
Keyword(s):  
Room Temperature ◽  
Composition Range ◽  
Piezoelectric Properties ◽  
Ferroelectric Ceramic ◽  
Lead Free ◽  
Dielectric Measurements ◽  
Polymorphic Phase Transition ◽  
Tetragonal Crystal ◽  
Tetragonal Crystal Structure ◽  
Dielectric And Piezoelectric Properties

Structural and dielectric investigations were carried out on a perovskite lead-free (Ba1−xCax)(Zr0.05Ti0.95)O3ferroelectric ceramic forx= 0.03, 0.05, 0.08, 0.10, 0.12 and 0.15. The room-temperature structural analysis reveals a crossover from orthorhombic to tetragonal crystal structure nearx= 0.10. A coexistence of tetragonal (P4mm) and orthorhombic (Pmm2) structure is observed in the composition range 0.05 ≤x≤ 0.10. The fraction of tetragonal phase increases from 27% forx= 0.05 to 71% forx= 0.10. The dielectric measurements show that the tetragonal to orthorhombic and rhombohedral to orthorhombic transition temperatures decrease with an increase in Ca2+content, while the cubic to tetragonal transition temperature remains the same. It is also shown that for the tetragonal to orthorhombic transition a phase coexistence occurs over a temperature range of about 18 K. The coexistence range covers room temperature for intermediate compositions:x= 0.05, 0.08 and 0.10. Therefore, higher dielectric and piezoelectric properties are observed in these compositions.

Lead-free p-type Mn:Cs3Cu2I5 perovskite with tunable dual-color emission through room-temperature grinding method

2021 ◽  
Author(s):  
Junfeng Qu ◽  
Shuhong Xu ◽  
Fan Liu ◽  
Zhuyuan Wang ◽  
Haibao Shao ◽  
...  
Keyword(s):  
Room Temperature ◽  
Lead Free ◽  
Grinding Method ◽  
Dual Color ◽  
P Type ◽  
Color Emission

Enhanced electrocaloric strengths at room temperature in (SrxBa1−x)(Sn0.05Ti0.95)O3 lead-free ceramics

2021 ◽  
Vol 871 ◽  
pp. 159519
Author(s):  
Sheng-Guo Lu ◽  
Xiongwei Lin ◽  
Jiang Li ◽  
Dandan Li ◽  
Yingbang Yao ◽  
...  
Keyword(s):  
Room Temperature ◽  
Lead Free ◽  
Lead Free Ceramics

Lead-free CsCu2I3 Perovskite Nanostructured Networks Gas Sensor for Selective Detection of Trace Nitrogen Dioxide at Room Temperature

2021 ◽  
pp. 1-1
Author(s):  
Xia Sun ◽  
Jie Yang ◽  
Zhilin Wu ◽  
Gang Meng ◽  
Xuezheng Guo ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Gas Sensor ◽  
Room Temperature ◽  
Lead Free ◽  
Selective Detection

The Characteristic of the La3Ga5SiO14 Single Crystal Grown by Vertical Bridgman Method in Ar Atmosphere

2006 ◽  
Vol 510-511 ◽  
pp. 842-845 ◽  
Author(s):  
Noriko Bamba ◽  
Kentaro Kato ◽  
Toshinori Taishi ◽  
Takayuki Hayashi ◽  
Keigo Hoshikawa ◽  
...  
Keyword(s):  
Melting Point ◽  
Single Crystal ◽  
Single Crystals ◽  
Room Temperature ◽  
Color Change ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Piezoelectric Constant ◽  
Interstitial Oxygen ◽  
Vertical Bridgman

Langasite (La3Ga5SiO14: denoted by LGS) single crystal is one of the lead free piezoelectric materials with high piezoelectricity that is maintained up to its melting point (1470°C). Although LGS single crystals have usually been grown by Czochralski (CZ) method in oxygen contained atmosphere to prevent evaporation of Ga, they were grown by the vertical Bridgman (VB) method in Ar atmosphere without oxygen, and their properties were evaluated in this work. Transparent and colorless LGS single crystals were successfully obtained without Ga evaporation by the VB method in Ar atmosphere, and their resistivity at room temperature was much higher than that grown by conventional CZ method. Piezoelectric constant d11 of the crystal grown by the VB method was 6 x 10-12 C/N, which was close to that of the crystal grown by CZ method. The colorless transparent LGS single crystal turned to orange and its resistivity decreased by annealing in air. Since an orange-colored transparent LGS single crystal has been grown by conventional CZ method, this indicates that color change and the resistivity decrease of LGS crystal is caused by extra interstitial oxygen atoms in the crystal.

Large electrocaloric efficiency over a broad temperature span in lead-free BaTiO3-based ceramics near room temperature

2017 ◽  
Vol 111 (20) ◽  
pp. 202902 ◽  
Author(s):  
Tangyuan Li ◽  
Xinyu Liu ◽  
Sheng Shi ◽  
Yihao Yin ◽  
Hongfa Li ◽  
...  
Keyword(s):  
Room Temperature ◽  
Lead Free

Effect of Sintering Temperature on Structure and Dielectric Properties of Lead Free K0.5Na0.5NbO3 Prepared via Hot Isostatic Pressing

2017 ◽  
Vol 888 ◽  
pp. 42-46 ◽  
Author(s):  
Fatin Khairah Bahanurdin ◽  
Julie Juliewatty Mohamed ◽  
Zainal Arifin Ahmad
Keyword(s):  
Grain Size ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Hot Isostatic Pressing ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Tangent Loss ◽  
Isostatic Pressing ◽  
Tan Δ

In this research, alkaline niobate known as K0.5Na0.5NbO3 (KNN) lead-free piezoelectric ceramic was synthesis by solid state reaction method which pressing at different sintering temperatures (1000 °C and 1080 °C) prepared via hot isostatic pressing (HIP)). The effect of sintering temperature on structure and dielectric properties was studied. The optimum sintering temperature (at 1080 °C for 30 minutes) using hot isostatic pressing (HIP) was successfully increase the density, enlarge the particle grain size in the range of 0.3 µm – 2.5 µm and improves the dielectric properties of K0.5Na0.5NbO3 ceramics. The larger grain size and higher density ceramics body will contribute the good dielectric properties. At room temperature, the excellent relative permittivity and tangent loss recorded at 1 MHz (ɛr = 5517.35 and tan δ = 0.954), respectively for KNN1080HIP sample. The KNN1080HIP sample is also exhibits highest relative density which is 4.485 g/cm3. The ɛr depends upon density and in this work, the density increase as the sintering temperature increase, which resulting the corresponding ɛr value also increases.

Enhanced electrocaloric effect in lead-free organic and inorganic relaxor ferroelectric composites near room temperature

2018 ◽  
Vol 112 (19) ◽  
pp. 193902 ◽  
Author(s):  
Haibibu Aziguli ◽  
Xin Chen ◽  
Yang Liu ◽  
Guang Yang ◽  
Ping Yu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Relaxor Ferroelectric ◽  
Lead Free ◽  
Electrocaloric Effect

Lead-free hybrid ferroelectric material based on formamidine: [NH2CHNH2]3Bi2I9

2019 ◽  
Vol 7 (10) ◽  
pp. 3003-3014 ◽  
Author(s):  
Przemysław Szklarz ◽  
Anna Gągor ◽  
Ryszard Jakubas ◽  
Piotr Zieliński ◽  
Anna Piecha-Bisiorek ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Ferroelectric Material ◽  
Lead Free ◽  
Ferroelectric Crystals ◽  
Complex Sequences

Novel room-temperature ferroelectric crystals with complex sequences of phase transitions.

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