Dielectric Relaxations of Y-Doped ZrO2 Single Crystal

Yamamura, Hiroshi; Yagi, Yuhji; Kakinuma, Katsuyoshi

doi:10.2109/jcersj2.115.546

Cited by 18 publications

(18 citation statements)

References 13 publications

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“…It is suggested that dispersion of σ ac occurs due to the dipole polarization and that impedance spectra indicates movement of dipole. In addition, we have been reported similar behavior in single crystal of 9mol% Y 2 O 3 stabilized ZrO 2 without grain boundary [10]. Therefore, the dispersion of σ ac in the oxide-ion conductors is not necessarily contribution by grain boundary resistivity.…”

Section: Transaction Of the Materials Research Society Of Japansupporting

confidence: 54%

“…The detail explanations concerning the theoretical treatment of dielectric properties for oxide-ion conductors are given elsewhere [5][6][7][8][9][10]. Therefore, the apparent dielectric constant (ε r ′) can be given by the following equation (1), assuming the presence of various Debye-type dipoles with multiple relaxation times: (1) where ω, ε r0i , and τ i represent the angular frequency (=2πf), the dielectric constant at the low frequency limit due to the i-th Debye-type polarization and the i-th dipole relaxation time (=1/2πf i ), respectively.…”

Section: Transaction Of the Materials Research Society Of Japanmentioning

confidence: 99%

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Oxide-ion conduction and dielectric relaxations in Ca-stabilized ZrO2

Yagi

Takayama

Yamamura

2009

Trans. Mat. Res. Soc. Japan

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The dielectric properties of Ca-stabilized ZrO 2 (Zr 0.9 Ca 0.1 O 2-δ , 10CSZ) which is an oxide ion conductor were investigated. Numerical analyses for the frequency dependence of dielectric constant (ε r ′) and dielectric loss factors (ε r ″) revealed that the dielectric properties were made up of Debye-type polarization due to dopant-vacancy associates [Ca zr ″-V o¨] and interfacial polarization at electrolyte-electrode. Two Debye-type relaxations were observed. This result implies the existence of two dopant-vacancy associates with different distances. Moreover, by using the dielectric constants obtained from the numerical analysis, the frequency dependences of ac conductivity (σ ac ) and dielectric loss tangent (tanδ) were also explained. KEYWORDS: oxide-ion conductor, fluorite-type structure, dielectric relaxation, Debye-type polarization, dopant-vacancy associate IntroductionThe oxide-ion conductors are used in various applications, such as oxygen sensors, oxygen pumps, solid oxide fuel cells (SOFCs), etc. However, since their operation temperatures are very high, the decrease in the operating temperature is required to achieve efficient operation and high performance. For oxide-ion conduction, many researchers have extensively investigated the electrical properties for fluorite-based oxides, ZrO 2 and CeO 2, and perovskite-based oxides, LaGaO 3, and Ba 2 In 2 O 5 [1-4]. Oxide-ion conductivity was estimated by using both ac impedance method and/or dc four-probe method and the relationships between activation energy and crystal chemical factors have been discussed. It has been clarified that the material with high conductivity has a highly symmetrical structure, relatively large unit cell free volume, disordered oxygen vacancies and other crystal properties that may be the dominant parameters of oxide-ion conductivity.On the other hand, experimental dates concerning the conduction mechanism are limited. Then, we paid attention to the dielectric properties of oxide-ion conductor, in order to reveal the polarization mechanism of the oxide-ions and the vacancy-dopant pairs. Recently, the group of present authors have clarified that the frequency dependence of dielectric constant (ε r ′) and dielectric loss factors (ε r ″) in the Ca, Nd, Sm, or Yb-doped CeO 2 systems, which are typical oxide ion conductor [5][6][7][8]. It was revealed that the dielectric properties can be made up of Debye-type polarization due to dopant-vacancy associates [Ca zr ″-V o¨] and interfacial polarization of electrolyte-electrode. In addition, when the dielectric measurement was carried out for the sample with oxide electrode La 0.6 Ca 0.4 MnO 3 (LCM), the observed dielectric properties are remarkably different from those of platinum electrode [9]. For this phenomenon, it was speculated that in the case of oxide electrode, oxide-ion of electrode can occupy directly the oxygen-vacancy site of the electrolyte, resulting in the decrease in the dopant-vacancy associate.In the present study, we tried to apply the numerical analysis of c...

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Section: Transaction Of the Materials Research Society Of Japansupporting

confidence: 54%

Section: Transaction Of the Materials Research Society Of Japanmentioning

confidence: 99%

Oxide-ion conduction and dielectric relaxations in Ca-stabilized ZrO2

Yagi

Takayama

Yamamura

2009

Trans. Mat. Res. Soc. Japan

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“…The dispersion in electrical properties was assigned to charge carrier relaxation and fitted to an approximately Gaussian distribution of relaxation times (17) . Single crystals of YSZ9 showed dispersions in permittivity, from which tan peaks were extracted and attributed to defect associates involving substitutional Y and oxygen vacancies (18) .…”

Section: Introductionmentioning

confidence: 99%

Dipolar relaxation and impedance of an yttria-stabilised zirconia ceramic electrolyte

Hernández

West

2016

J. Mater. Chem. A

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“…Our research group reported that the relationship between oxide ion conduction and dielectric relaxation from the viewpoints of dielectric constant, dielectric loss factor and loss tangent (tanδ) in the Sm, Nd, or Yb doped CeO 2 [4][5][6] and Y or Ca stabilized ZrO 2 [7,8] systems. According to those studies, the dielectric properties of oxide ion conductors can be explained by the superposition of Debye-type polarization due to the dopant-vacancy associates [Ln Ce ′-V O¨] ‧ (Ln: dopant cation) and charge current on electrolyte-electrode interface.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the dielectric relaxation measurement of 9 mol% Y 2 O 3 doped ZrO 2 single crystal was carried out to explain the grain boundary effect [7].…”

Section: Introductionmentioning

confidence: 99%

Oxide ion conduction and dielectric relaxations for Ce1-xYxO2-x/2 system.

Satake

Takayama

Yamamura

2010

Trans. Mat. Res. Soc. Japan

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Relationship between oxide ion conduction and dielectric relaxation in the Ce 1-x Y x O 2-x/2 system (0 x 0.5) was investigated in order to clarify the dynamic properties of oxide ion conduction. The frequency dependence of dielectric constant was explained by the superposition of Debye-type polarization due to dopant-vacancy associates and charge current on electrolyteelectrode interface. The frequency dependence of ac conductivity was also explained by use of the dielectric parameters obtained from the numerical analysis of dielectric constant. Additionally, the polarization hysteresis curves of the oxide ion conductor were also measured to investigate the Debye-type dipoles in detail. As a result, it was found that the observed remanent polarizations have a close relation with the polarization of dopant-vacancy associates.Key words: CeO 2 , dielectric relaxation, fluorite type structure, oxide ion conduction IntroductionOxide ion conductors play an important role in such applications as oxygen sensors, oxygen pumps and solid oxide fuel cells (SOFCs) etc. Since SOFCs are required to decrease the operation temperature, high ionic conductivity is desired. Therefore, various materials having fluorite, perovskite and their related structures have been investigated. So far, the oxide ion conduction has been investigated by the dc four-probe and/or the ac impedance methods, and then the relationship between the crystal structure and activation energy for oxide ion conduction was discussed. As the result, many researchers suggest many factors for oxide ion conduction, for example, unit cell free volume, saddle point, ordering of oxygen vacancy and dopant-vacancy association etc. [1][2][3] However, the dominant factors for oxide ion conduction have not been clear.The oxide ion conduction has a close relation with the electric dipole polarizations of oxygen vacancy. Our research group reported that the relationship between oxide ion conduction and dielectric relaxation from the viewpoints of dielectric constant, dielectric loss factor and loss tangent (tanδ)

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Dielectric Relaxations of Y-Doped ZrO2 Single Crystal

Cited by 18 publications

References 13 publications

Oxide-ion conduction and dielectric relaxations in Ca-stabilized ZrO<sub>2</sub>

Oxide-ion conduction and dielectric relaxations in Ca-stabilized ZrO<sub>2</sub>

Dipolar relaxation and impedance of an yttria-stabilised zirconia ceramic electrolyte

Oxide ion conduction and dielectric relaxations for Ce<sub>1-<i>x</i></sub>Y<sub><i>x</i></sub>O<sub>2-<i>x</i>/2</sub> system.

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