Giant dielectric permittivity and electronic structure in (Al+Sb)co-doped TiO2 ceramics

Tuichai, Wattana; Srepusharawoot, Pornjuk; Swatsitang, Ekaphan; Danwittayakul, Supamas; Thongbai, Prasit

doi:10.1016/j.mee.2015.02.052

Cited by 55 publications

(35 citation statements)

References 37 publications

(46 reference statements)

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“…2. The grain size of all YNTO ceramics reaches the largest value when x = 0.02, which is consistent with Nb, In and Al, Sb co-doped TiO 2 ceramics 1, 22 . For 0.04 sample, the EDS results of the as pointed region confirm the elemental ratio of Y:Nb:Ti is close to 1:1:1 (Y: Nb: Ti = 6.2:7.73:7.09), which is in accordance with the XRD results for the YNbTiO 6 phase (the elemental ratio in another zone is also close to 1:1:1, as is shown in Fig.…”

Section: Resultssupporting

confidence: 81%

Dielectric properties of Y and Nb co-doped TiO2 ceramics

Wang

Zhang

et al. 2017

Sci Rep

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In this work, the (Y0.5Nb0.5)xTi1−xO2 (x = 0.001, 0.01, 0.02, 0.04, 0.06 and 0.1) ceramics (as called YNTO) were fabricated by synthesized through a standard solid-state reaction. As revealed by the X-ray diffraction (XRD) spectra, the YNTOs exhibit tetragonal rutile structure. Meanwhile, the grain size of YNTO ceramics increased and then decreased with the increase of x value, and the largest value reached when x = 0.02. All the YNTO samples display colossal permittivity (~102–105) over a wide temperature and frequency range. Moreover, the optimal ceramic, (Y0.5Nb0.5)0.02Ti0.98O2, exhibits high performance over a broad temperature range from 20 °C to 180 °C; specifically, at 1 kHz, the dielectric constant and dielectric loss are 6.55 × 104 and 0.22 at room temperature, and they are 1.03 × 105 and 0.11 at 180 °C, respectively.

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Section: Resultssupporting

confidence: 81%

Dielectric properties of Y and Nb co-doped TiO2 ceramics

Wang

Zhang

et al. 2017

Sci Rep

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“…The grain size decreased with the increase in Zr doping level, which may be related to the liquid phase sintering mechanism. Normally, the grain growth of a polycrystalline ceramics is caused by mass transport across the grain boundary by diffusion of ions or atoms . It would result in the movement of the grain boundary.…”

Section: Resultsmentioning

confidence: 99%

“…It would result in the movement of the grain boundary. On the heating process, if the liquid phase in the ceramic microstructure was formed, it can enhance the diffusion rate of ions . This leads to a large enhancement of the grain boundary mobility .…”

Section: Resultsmentioning

confidence: 99%

Colossal permittivity in TiO₂ co‐doped by donor Nb and isovalent Zr

2017

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Effect of isovalent Zr dopant on the colossal permittivity (CP) properties was investigated in (Zr + Nb) co‐doped rutile TiO2 ceramics, i.e., Nb0.5%ZrxTi1−xO2. Compared with those of single Nb‐doped TiO2, the CP properties of co‐doped samples showed better frequency‐stability with lower dielectric losses. Especially, a CP up to 6.4 × 104 and a relatively low dielectric loss (0.029) of x = 2% sample were obtained at 1 kHz and room temperature. Moreover, both dielectric permittivity and loss were nearly independent of direct current bias, and measuring temperature from room temperature to around 100°C. Based on X‐ray photoelectron spectroscopy, the formation of oxygen vacancies was suppressed due to the incorporation of Zrions. Furthermore, it induced the enhancement of the conduction activation energy according to the impedance spectroscopy. The results will provide a new routine to achieve a low dielectric loss in the CP materials.

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“…9,10 In the new colossal permittivity materials, simultaneous donor and acceptor substitutions into TiO 2 are considered to create the local combination of a partially delocalized electron, as a result of the formation of a defectdipole complex/cluster. [13][14][15] Therefore, it should be feasible that co-doping of monovalent or bivalent elements with Nb into TiO 2 may also lead to colossal permittivity effects on the conditions under which the charge balance is kept. Although the grain boundary capacitance effect is considered to contribute to the colossal dielectric properties, 11,12 the newly discovered co-doped TiO 2 materials would provide more choices to tune and optimize dielectric properties through the combination of substituted ions.…”

Section: Introductionmentioning

confidence: 99%

Colossal permittivity properties of Zn,Nb co-doped TiO₂with different phase structures

et al. 2015

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Colossal permittivity properties were studied in Zn,Nb co-doped TiO 2 with different phase structures. The (Zn 1/3 Nb 2/3 ) 0.05 Ti 0.95 O 2 rutile ceramics were prepared by the solid state sintering technique, while the amorphous and anatase films were respectively fabricated by a pulsed laser deposition method and a subsequent rapid thermal annealing. The ceramics showed a frequency (10 2 -10 6 Hz) independent dielectric response with a colossal dielectric permittivity (B30 000), and a relatively low dielectric loss (B0.05) at room temperature. The excellent colossal permittivity properties are comparable to those of the previously reported rutile TiO 2 ceramics by co-doping trivalent and pentavalent elements.For amorphous films, the dielectric permittivity decreased, and the dielectric loss increased slightly compared to those of the ceramics. Compared with the amorphous thin films, the annealed anatase ones exhibited a simultaneous increase in both dielectric permittivity and loss at low frequency while kept almost unchanged at high frequency. These results suggest that co-doping of bivalent elements with Nb into TiO 2 with various phase structures can yield colossal permittivity effects, including ultrahigh dielectric permittivity, relatively low dielectric loss. Furthermore, the colossal permittivity properties may be mainly attributed to the effect of the electron-pinned defect-dipoles in Zn,Nb co-doped TiO 2 with different phase structures rather than the grain boundary capacitance effect. Besides, the frequency and bias dependent dielectric properties were also investigated in thin film forms, which could be affected by the electrode-film interface and mobile ions. Our results are helpful for not only investigating the new class of colossal permittivity materials, but also developing dielectric thin film device applications.

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Giant dielectric permittivity and electronic structure in (Al+Sb)co-doped TiO2 ceramics

Cited by 55 publications

References 37 publications

Dielectric properties of Y and Nb co-doped TiO2 ceramics

Dielectric properties of Y and Nb co-doped TiO2 ceramics

Colossal permittivity in TiO₂ co‐doped by donor Nb and isovalent Zr

Colossal permittivity properties of Zn,Nb co-doped TiO₂with different phase structures

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Giant dielectric permittivity and electronic structure in (Al+Sb)co-doped TiO2 ceramics

Cited by 55 publications

References 37 publications

Dielectric properties of Y and Nb co-doped TiO2 ceramics

Dielectric properties of Y and Nb co-doped TiO2 ceramics

Colossal permittivity in TiO2 co‐doped by donor Nb and isovalent Zr

Colossal permittivity properties of Zn,Nb co-doped TiO2with different phase structures

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Colossal permittivity in TiO₂ co‐doped by donor Nb and isovalent Zr

Colossal permittivity properties of Zn,Nb co-doped TiO₂with different phase structures