Dielectric relaxation studies of Ba-doping effects on the oxygen-ion diffusion and phase transition in La2Mo2−yWyO9 ceramics

2009 ◽  
Vol 404 (12-13) ◽  
pp. 1757-1760 ◽  
Author(s):  
D. Li ◽  
X.P. Wang ◽  
Z. Zhuang ◽  
Q.F. Fang
Keyword(s):  
Phase Transition ◽  
Dielectric Relaxation ◽  
Ion Diffusion ◽  
Oxygen Ion ◽  
Doping Effects ◽  
Relaxation Studies ◽  
Oxygen Ion Diffusion

Influence of Tungsten Doping in La2Mo2O9 Oxide-Ion Conductors by Dielectric Relaxation Measurements

2011 ◽  
Vol 130-134 ◽  
pp. 3302-3305
Author(s):  
Dan Li ◽  
Xiang Hu Li
Keyword(s):  
Phase Transition ◽  
Dielectric Relaxation ◽  
Ion Diffusion ◽  
Ion Distribution ◽  
Β Phase ◽  
Oxygen Ion ◽  
Relaxation Measurements ◽  
Temperature Relaxation ◽  
Oxygen Ion Diffusion ◽  
Tungsten Doping

The effects of tungsten doping in La2Mo2–yWyO9 (y =0, 0.25, 0.5, 1.0, 1.4) samples were studied using dielectric relaxation measurements. The results indicate that the solubility of W6+ in La2Mo2O9 sample is about 25mol%, W6+ can suppress the α/β phase transition in the La2Mo2O9. Additional to the low-temperature relaxation peak Pd associated with oxygen ion diffusion, a new dielectric loss peak Ph associated with a phase transition from the static disordered state to the dynamic disordered state of oxygen ion distribution was observed around 740 K. The conductivity of La2Mo1.9W0.1O9 sample is higher than that of the pure La2Mo2O9, and then decrease with the increasing of the tungsten doping in La2Mo2–yWyO9 (y = 0.5, 1.0) samples in the whole measurement temperature.

The Oxygen-Ion Diffusion and Phase Transition in the La2Mo2-xWxO9 Samples Measured by Internal Friction Method

2012 ◽  
Vol 160 ◽  
pp. 8-11 ◽  
Author(s):  
Dan Li ◽  
Xiang Hu Li
Keyword(s):  
Phase Transition ◽  
Internal Friction ◽  
Ion Diffusion ◽  
Oxygen Ion ◽  
Temperature Spectra ◽  
Friction Temperature ◽  
Temperature Relaxation ◽  
Friction Method ◽  
Two Peaks ◽  
Oxygen Ion Diffusion

The effects of tungsten doping on the oxygen-ion diffusion and the phase transition in La2Mo2–xWxO9 samples (x = 0.5, 0.75, 1.0, 1.2) were studied using internal friction method. The results show that two peaks were detected in the internal friction-temperature spectra in the La2Mo2-xWxO9 samples, the low-temperature relaxation peak is associated with oxygen ion diffusion, and the high-temperature peak is associated with a phase transition from the static disordered state to the dynamic disordered state of oxygen ion/vacancy distribution.

Dielectric Relaxation Measurements in La2Mo1.5W0.5O9 Oxide-Ion Conductor

2014 ◽  
Vol 952 ◽  
pp. 51-54
Author(s):  
Dan Li ◽  
Jun Li ◽  
Chong Chen ◽  
Lin Qi ◽  
Xiang Hu Li
Keyword(s):  
Phase Transition ◽  
Dielectric Relaxation ◽  
Ion Diffusion ◽  
Ion Distribution ◽  
Ion Conductor ◽  
Oxide Ion Conductor ◽  
Β Phase ◽  
Oxygen Ion ◽  
Relaxation Measurements ◽  
Temperature Relaxation

The effects of tungsten doping in La2Mo1.5W0.5O9 sample were studied using dielectric relaxation measurements. The results indicate that W6+ can suppress the α/β phase transition in the La2Mo2O9. Additional to the low-temperature relaxation peak Pd associated with oxygen ion diffusion, a new dielectric loss peak Ph associated with a phase transition from the static disordered state to the dynamic disordered state of oxygen ion distribution was observed around 740 K.

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.

Influence of Fe Doping on the Oxygen-Ion Diffusion and Electrical Conduction of La1.95K0.05Mo2-XFexO9-δ

2010 ◽  
Vol 663-665 ◽  
pp. 506-510
Author(s):  
Chun Li ◽  
Da Li ◽  
Qian Feng Fang
Keyword(s):  
Phase Transition ◽  
Fe Doping ◽  
Conductivity Measurements ◽  
Ion Diffusion ◽  
Solid Reaction ◽  
Ion Conductor ◽  
Reaction Method ◽  
Oxygen Ion ◽  
Oxygen Ion Conductor ◽  
Oxygen Ion Diffusion

Based on the oxygen ion conductor La1.95K0.05Mo2O8.95, a series of Fe-doped samples La1.95K0.05Mo2-xFexO9- (x=0, 0.025, 0.05, 0.1) were prepared with conventional solid reaction method. The effects of Fe doping on the structure, oxygen ion diffusion and electrical conductivity were studied. Based on the results of conductivity measurements, it can be concluded that Fe doping can improve the conductivity obviously, and doping of both Fe and K samples have better conductivity, which successfully suppresses the phase transition.

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