Influence of tetragonality and secondary phase on the Curie temperature for barium titanate ceramics

Using titanium nitrate solution stabilized by chelation, amorphous fine particles of the Ba-Ti-O system were prepared by the mist decomposition method in air. After calcination of these particles, barium titanate ceramics were prepared using the hot uniaxial pressing method, and various properties were investigated. As a result, the grain sizes could be controlled over the range from 58 nm to 187 nm by the sintering temperatures and/or the calcination temperatures, keeping the density almost constant. Moreover, the dielectric properties of the samples showed that the relative permittivity decreased with decreasing grain size, and Curie temperature also shifted to lower temperatures in the same way. In this study, we first found that Curie temperature existed in the barium titanate ceramics with grain sizes from 58 to 147 nm.

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Dielectric Properties of Barium Titanate Ceramics Modified by CuO in Different Methods

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.463-464.276 ◽

2012 ◽

Vol 463-464 ◽

pp. 276-280 ◽

Cited By ~ 1

Author(s):

Dan Su ◽

Yu Wang ◽

Wan Ping Chen ◽

Helen Lai Wah Chan ◽

Li Na Bing

Keyword(s):

Barium Titanate ◽

Curie Temperature ◽

Perovskite Phase ◽

Hexagonal Phase ◽

Boundary Phase ◽

X Ray Diffraction ◽

X Ray ◽

Pure Perovskite Phase ◽

The Difference ◽

Titanate Ceramics

CuO has been doped solely and together with BaO and SiO2 into barium titanate by mixing and calcination. X-ray diffraction showed that the sample doped by CuO-BaO has stable second hexagonal phase while the samples doped by CuO, CuO-SiO2 were of a pure perovskite phase. For CuO-BaO doping, the Curie temperature was decreased accompanied with higher εmax; while for CuO doping and CuO-SiO2 codoping, the Curie temperature was increased with εmax decreased. The difference can be explained considering that Cu2+ ion could not only incorporate into the BaTiO3 lattice, but also assemble in the boundary phase when CuO was doped solely. Besides, the mechanisms of CuO doping and SiO2 doping could happen at one time.

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Preparation of barium titanate–bismuth magnesium titanate ceramics with high Curie temperature and their piezoelectric properties

Journal of the Ceramic Society of Japan ◽

10.2109/jcersj2.118.683 ◽

2010 ◽

Vol 118 (1380) ◽

pp. 683-687 ◽

Cited By ~ 22

Author(s):

Satoshi WADA ◽

Keisuke YAMATO ◽

Petr PULPAN ◽

Nobuhiro KUMADA ◽

Bong-Yeon LEE ◽

...

Keyword(s):

Barium Titanate ◽

Curie Temperature ◽

Piezoelectric Properties ◽

High Curie Temperature ◽

Magnesium Titanate ◽

Titanate Ceramics

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Investigation on the Correlation between Structural and Electrical Properties of Lanthanum Doped Barium Titanate Ceramics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.860.99 ◽

2016 ◽

Vol 860 ◽

pp. 99-104

Author(s):

Masum Billah ◽

Md Miftaur Rahman

Keyword(s):

Grain Size ◽

Electrical Properties ◽

Barium Titanate ◽

Curie Temperature ◽

Raw Materials ◽

Structure Property ◽

Structural And Electrical Properties ◽

Doped Barium Titanate ◽

Titanate Ceramics ◽

Relationship Of

The structure-property relationship of 0.3, 0.5 and 0.7mole% lanthanum (La2O3) doped Barium titanate (BaTiO3) ceramics prepared by solid state sintering under different sintering conditions were investigated in this research. The raw materials were La2O3 (grain size=~80nm) and BaTiO3 (grain size=100nm) powders. Field Emission Scanning Electron Microscope (FE-SEM) was used to examine grain size and surface morphology of sintered pellets & X-Ray Diffraction analysis was conducted to identify crystal structure. The results showed significantly improved grain size and electrical properties of BaTiO3 for 0.5 mole% La2O3 with desired grain size (0.8-1.3μm), high densification (>90% theoretical density) and stable dielectric constant (12700) at room temperature (f=100Hz) by lowering curie temperature around 30oC by sintering at 1300oC for 8 hrs. A gradual deterioration follows with increased doping concentration. So the research revealed that proper La3+ concentration can inhibit grain size and lower Curie temperature hence significantly improving the electrical properties of BaTiO3 ceramics.

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