Evolution of internal friction and dielectric relaxation peaks in La2Mo2O9-based oxide-ion conductors assessed by a nonlinear peak-fitting method

2005 ◽  
Vol 202 (6) ◽  
pp. 1041-1047 ◽  
Author(s):  
Q. F. Fang ◽  
X. P. Wang ◽  
G. G. Zhang ◽  
Z. J. Cheng
Keyword(s):  
Internal Friction ◽  
Dielectric Relaxation ◽  
Peak Fitting ◽  
Fitting Method ◽  
Oxide Ion Conductors ◽  
Oxide Ion ◽  
Ion Conductors

Internal Friction Study of the Rare Earth Ion Substituted Fast Oxide-Ion Conductors (La1-ΧreΧ)2Mo2O9 (Re=Nd, Gd)

2012 ◽  
Vol 184 ◽  
pp. 110-115
Author(s):  
X.P. Wang ◽  
J. Hu ◽  
Zhong Zhuang ◽  
Tao Zhang ◽  
Qian Feng Fang
Keyword(s):  
Phase Transition ◽  
Rare Earth ◽  
Internal Friction ◽  
Diffusion Processes ◽  
Rare Earth Ion ◽  
Disorder Transition ◽  
Oxide Ion Conductors ◽  
Oxide Ion ◽  
The Rare Earth ◽  
Ion Conductors

The relaxation and phase transition behaviors of rare-earth ion substituted fast oxide-ion conductors (La1-xRex)2Mo2O9 (Re=Nd, Gd) were investigated by internal friction (IF) measurement in the temperature range 300 K - 950 K. Three different IF peaks (labeled as PL, PH, and PG, respectively) were observed in the rare-earth ion doped La2Mo2O9 samples. Peak PL corresponds to short diffusion processes of oxygen ions among different oxygen vacancy sites. Peak PH is associated with the static/dynamic disorder transition in oxygen ion distribution. Peak PG is a newly discovered peak embodying phase transition-like characteristics and is suggested to be related to order-disorder transition associated with the rearrangement of La/ Re sub-lattice.

Dielectric Relaxation Measurements in La1.94Ba0.06Mo2-yWyO9-δ (y=0, 1.0) Oxide-Ion Conductors

2014 ◽  
Vol 662 ◽  
pp. 20-23
Author(s):  
Dan Li ◽  
Bo Wang ◽  
Pei Gong ◽  
Jie Li ◽  
Xiang Hu Li
Keyword(s):  
Phase Transition ◽  
Dielectric Relaxation ◽  
Transition Process ◽  
Ion Diffusion ◽  
Oxygen Ion ◽  
Phase Transition Process ◽  
Relaxation Measurements ◽  
Oxide Ion Conductors ◽  
Oxide Ion ◽  
Ion Conductors

The influence of barium doping on the oxygen-ion diffusion and phase transition in the La2Mo2-yWyO9-δ (y=0, 1.0) oxide-ion conductors has been systematically investigated via dielectric techniques. In the Ba-doped La2Mo2O9 samples there are only two dielectric relaxation peaks Pd1 and Pd2, which are associated with the short-distance diffusion of oxygen vacancies. But in the Ba-doped La2MoWO9 members, three peaks are detected, including peak Pd1, Pd2, and peak Ph. The last is associated with the phase transition process from the static disordered state to the dynamic disordered state of oxygen ion/vacancy distribution.

Relaxation Effects in La2Mo2O9-Based Oxide-Ion Conductors

2006 ◽  
Vol 115 ◽  
pp. 193-202 ◽  
Author(s):  
Qian Feng Fang ◽  
X.P. Wang ◽  
Z.G. Yi ◽  
Z.J. Cheng
Keyword(s):  
Oxygen Vacancy ◽  
Internal Friction ◽  
Dielectric Relaxation ◽  
Oxygen Vacancies ◽  
Vacancy Diffusion ◽  
Doping Content ◽  
Higher Temperature ◽  
Oxide Ion Conductors ◽  
Oxide Ion ◽  
Oxygen Vacancy Diffusion

The novel oxide-ion conductors (La1-xAx)2Mo2O9-δ (A = Ca, Bi, K, x = 0 ~ 0.075) are investigated in this paper by internal friction and dielectric relaxation techniques. Two relaxation peaks associated with the short-distance diffusion of oxygen vacancies were observed, indicating that there are at least two relaxation processes for diffusion of oxygen vacancies. Doping at La site with different elements shifts both relaxation peaks toward higher temperature and increases the activation energy of oxygen vacancy diffusion. In the case of internal friction, the height of the higher-temperature peak (dominant component) decreases with increasing doping content. In the case of dielectric relaxation, however, the variation of the peak heights as a function of doping content exhibits a maximum around 2.5 % K and 5 % Bi. After properly doping, the conductivity at low temperature of doped La2Mo2O9 increases by different degrees, and a peak of the conductivity at 500° C is observed in the doping content where the highest dielectric relaxation peak appears. Based on the experimental results and the crystalline structure, the mechanism of oxygen vacancy diffusion in (La1-xAx)2Mo2O9-δ samples is discussed.

Ionic Conductivities and Phase Transition of La2Mo2-xAlxO9-δ

2012 ◽  
Vol 160 ◽  
pp. 391-394
Author(s):  
Xiang Hu Li ◽  
Dan Li
Keyword(s):  
Phase Transition ◽  
Dielectric Relaxation ◽  
Ionic Conductivities ◽  
Aluminum Doping ◽  
Β Phase ◽  
Relaxation Measurements ◽  
Oxide Ion Conductors ◽  
Oxide Ion ◽  
Ion Conductors

The influence of aluminum doping on the ionic conductivities and phase transition in the La2Mo2–xAlxO9-δ(x = 0.1, 0.2, 0.3) oxide-ion conductors has been investigated by XRD, DSC and dielectric relaxation measurements. The results indicate that the solubility of Al3+ in La2Mo2O9 sample is about 10mol%, Al3+ can not suppress the α/β phase transition in the La2Mo2O9, and the aluminum substituted La2Mo2O9 has a higher conductivity in whole temperature than that of pure La2Mo2O9.

scholarly journals Ga-doped Ca12Al14O33 mayenite oxide ion conductors: synthesis, defects, and electrical properties

RSC Advances ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 3809-3815 ◽  
Author(s):  
Huaibo Yi ◽  
Yun Lv ◽  
Yanhui Wang ◽  
Xue Fang ◽  
Victoria Mattick ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Bulk Conductivity ◽  
Oxide Ion Conductors ◽  
Ga Doping ◽  
Oxide Ion ◽  
Ion Conductors

The bulk conductivity of Ca12Al14O33 can be apparently enhanced by Ga-doping on the Al sites.

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