scholarly journals Concurrent La and A-Site Vacancy Doping Modulates the Thermoelectric Response of SrTiO3: Experimental and Computational Evidence

2017 ◽  
Vol 9 (48) ◽  
pp. 41988-42000 ◽  
Author(s):  
Feridoon Azough ◽  
Samuel S. Jackson ◽  
Dursun Ekren ◽  
Robert Freer ◽  
Marco Molinari ◽  
...  
Keyword(s):  
A Site ◽  
Vacancy Doping ◽  
Site Vacancy

The Effect of (Li,Ce) Doping in Aurivillius Phase Material Na0. 5Bi4.5Ti4O15

2010 ◽  
Vol 146-147 ◽  
pp. 89-92
Author(s):  
Zhi Gang Gai ◽  
Yuan Yuan Feng ◽  
Jin Feng Wang ◽  
Hong Wu
Keyword(s):  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Aurivillius Phase ◽  
Promising Candidate ◽  
High Tc ◽  
Ce Modification ◽  
A Site ◽  
Site Vacancy ◽  
Dielectric And Piezoelectric Properties ◽  
State Processing

Na0.5Bi4.5Ti4O15-based materials with A-site vacancy were synthesized using conventional solid state processing. The (Li,Ce) modification of Na0.5Bi4.5Ti4O15-based materials resulted in the obvious improvement of the piezoelectric activity and dielectric permittivity. The dielectric and piezoelectric properties of Na0.5Bi4.5Ti4O15-based ceramics exhibiting a very stable temperature behavior, together with its high TC ~641oC, excellent piezoelectric coefficient ~28pC/N and very low temperature coefficient of resonant frequency, making the (Li,Ce) modified Na0.5Bi4.5Ti4O15-based ceramics a promising candidate for high temperature applications.

Structural investigation of the A-site vacancy in scheelites and the luminescence behavior of two continuous solid solutions A1–1.5xEux□0.5xWO4 and A0.64–0.5yEu0.24Liy□0.12–0.5yWO4 (A = Ca, Sr; □ = vacancy)

2015 ◽  
Vol 44 (13) ◽  
pp. 6175-6183 ◽  
Author(s):  
Pengfei Jiang ◽  
Wenliang Gao ◽  
Rihong Cong ◽  
Tao Yang
Keyword(s):  
Solid Solutions ◽  
Structural Characterization ◽  
Structural Investigation ◽  
Vacancy Mechanism ◽  
Charge Balance ◽  
A Site ◽  
Site Vacancy ◽  
Luminescence Behavior

A detailed structural characterization on A1–1.5xEux□0.5xWO4 and A0.64–0.5yEu0.24Liy□0.12–0.5yWO4 (A = Ca, Sr; □ = vacancy) prove the A-site vacancy mechanism for charge balance.

The role of ordered A1-site vacancies in belt nano-domains of Pb1−xBaxNb2O6 (PBN) solid solution

1996 ◽  
Vol 11 (3) ◽  
pp. 650-656 ◽  
Author(s):  
Xiaoyue Xiao ◽  
Yan Xu ◽  
Zhigang Zeng ◽  
Zhilun Gui ◽  
Longtu Li ◽  
...  
Keyword(s):  
Solid Solution ◽  
Phase Boundary ◽  
High Resolution Electron Microscopy ◽  
Quasi Equilibrium ◽  
Slow Cooling ◽  
Domain Structures ◽  
Resolution Electron ◽  
A Site ◽  
Anti Phase Boundary ◽  
Site Vacancy

The order-disorder states of the A-site vacancy of PBN solid solution affected by different thermal treatments were studied with the aid of High Resolution Electron Microscopy (HREM). PBN ceramics around the morphotropic phase boundary were prepared through two routes to control ordering degree of the A-site vacancy: (1) samples through quenching processes resulted in chaotic states of the A-site vacancies and misfit anti-phase boundary; (2) samples through slow cooling led to an ordered structure of the vacancies in the A1-site. The ordered A1-site vacancies were modulated by interchanges of the sublattices of the ordered vacancies and the Pb2+ cations in the A1-sites along both and orientations, forming a narrow discommensurate wall between two anti-phase domains. The anti-phase domains were observed as a regular belt structure with dimensions of about 45 nm × (≥120) nm. The belt nano-domain structures were a result of quasi-equilibrium thermodynamic processes.

scholarly journals Thermoelectric properties of p-type perovskite La0.95-xSrx□0.05CoO3 systems containing the A-site vacancy

2010 ◽  
Vol 35 (3) ◽  
pp. 503-506 ◽  
Author(s):  
Mayuka Anzai ◽  
Hiroshi Kawakami ◽  
Toshio Takayama ◽  
Hiroshi Yamamura
Keyword(s):  
Thermoelectric Properties ◽  
A Site ◽  
P Type ◽  
Site Vacancy

Thermoelectric properties of p-type perovskite compounds LaCoO3systems containing the A-site vacancy

2011 ◽  
Vol 18 (14) ◽  
pp. 142005 ◽  
Author(s):  
Mayuka Anzai ◽  
Hiroshi Kawakami ◽  
Miwa Saito ◽  
Hiroshi Yamamura
Keyword(s):  
Thermoelectric Properties ◽  
A Site ◽  
P Type ◽  
Site Vacancy

Effect of A-site vacancy order-disorder states on diffuse phase transition of the morphotropic phase boundary Pb1−xBaxNb2O6 ferroelectrics

1996 ◽  
Vol 11 (9) ◽  
pp. 2302-2308 ◽  
Author(s):  
Xiaoyue Xiao ◽  
Yan Xu ◽  
Zhigang Zeng ◽  
Zhilun Gui ◽  
Longtu Li ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Diffuse Phase Transition ◽  
Frequency Dispersion ◽  
Dielectric Constants ◽  
A Site ◽  
Curie Temperatures ◽  
Site Vacancy ◽  
Diffuse Phase

The effect of A-site vacancy order-disorder states on diffuse phase transition (DPT) of tungsten bronze Pb1−xBaxNb2O6 (PBN) ferroelectrics has been investigated. The A-site vacancy disordered PBN ceramics exhibit notable variations of the Curie temperatures (i.e., the temperatures at the dielectric maximum permittivities) up to 12 °C in response to frequency changed from 0.1 KHz to 100 KHz. The largest frequency dispersion occurred at the morphotropic phase boundary of 1 − X = 0.63, along with the lowest Curie point. In contrast, the A-site vacancy ordered PBN ceramics present little frequency dispersion in the range of 2 °C from 0.1 KHz to 100 KHz. Dielectric constants of the disordered PBN ceramics were generally higher than those of the ordered ones. In comparison with the ordered PBN ceramics, the Curie points of the disordered ceramics were shifted from lower to higher temperature as the Pb2+ cation percentage was decreased; i.e., the Curie temperatures of the disordered PBN ceramics were lower than those of the ordered ones when 1 − X ≥ 0.70, but higher when 1 − X ≤ 0.65. These differences are suggested to inherently result from the A-site vacancy order-disorder states. The relationship between the A-site vacancy order-disorder states and the dielectric properties has also been confirmed with studies of thermal hysteresis.

scholarly journals Controlling Multiple Orderings in Metal Thiocyanate Molecular Perovskites Ax{Ni[Bi(SCN)6]}

2020 ◽  
Author(s):  
Jie Yie Lee ◽  
Sanliang Ling ◽  
Stephen Argent ◽  
Mark Senn ◽  
Laura Cañadillas-Delgado ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Double Perovskites ◽  
Functional Theory ◽  
X Ray ◽  
Vacancy Ordering ◽  
A Site ◽  
Symmetry Mode ◽  
Site Vacancy

<p>We report four new A-site vacancy ordered thiocyanate double double perovskites,</p><p>A1􀀀xfNi[Bi(SCN)6]1􀀀x3 }, A = K<sup>+</sup>, NH4<sup>+</sup>, CH3(NH3)<sup>+</sup> (MeNH<sub>3</sub><sup>+</sup>) and C(NH<sub>2</sub>)<sub>3</sub><sup>+</sup> (Gua<sup>+</sup>), including the first examples of thiocyanate perovskites containing organic A-site cations. We show, using a combination of X-ray and neutron diffraction, that the structure of these frameworks depends on the A-site cation, and that these frameworks possess complex vacancy-ordering patterns and cooperative octahedral tilts distinctly different from atomic perovskites. Density functional theory calculations uncover the energetic origin of these complex orders and allow us to propose a simple rule to predict favoured A-site cation orderings for a given tilt sequence. We use these insights, in combination with symmetry mode analyses, to show that these complex orders offer a new route to non-centrosymmetric perovskites which render them as excellent candidates for</p><p>piezo- and ferroelectric applications.</p>

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