Hopping conduction and low-frequency dielectric relaxation in 5mol% Mn doped (Pb,Sr)TiO3 films

2008 ◽  
Vol 104 (10) ◽  
pp. 104113 ◽  
Author(s):  
J. Yang ◽  
X. J. Meng ◽  
M. R. Shen ◽  
L. Fang ◽  
J. L. Wang ◽  
...  
Keyword(s):  
Dielectric Relaxation ◽  
Low Frequency ◽  
Hopping Conduction ◽  
Mn Doped

scholarly journals Dielectric Relaxation, Local Structure and Lattice Dynamics in Mn-Doped Potassium Tantalate Ceramics

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4632
Author(s):  
Alexander Tkach ◽  
Abilio Almeida ◽  
Igor Levin ◽  
Joseph C. Woicik ◽  
Paula M. Vilarinho
Keyword(s):  
Dielectric Relaxation ◽  
Local Structure ◽  
Lattice Dynamics ◽  
Variable Temperature ◽  
Low Frequency ◽  
Characteristic Relaxation Time ◽  
Potassium Tantalate ◽  
Electric Dipoles ◽  
X Ray Absorption ◽  
Mn Doped

Alkaline niobate and tantalate perovskites have attracted attention as polar dielectrics for electronics and telecommunications. Here, we studied the polar behaviour, lattice dynamics, and local structure in conventionally processed K0.985Mn0.015TaO3±δ ceramics using a combination of variable-temperature dielectric and Raman spectroscopies, and X-ray absorption fine structure (XAFS) measurements, respectively. Mn doping induces a low-frequency dielectric relaxation in KTaO3 (KT), which follows the Arrhenius law with an activation energy U ≈ 105 meV and the characteristic relaxation time τ0 ≈ 4.6 × 10−14 s. Our XAFS results support preferential Mn occupancy of the cuboctahedral sites as Mn2+, with these cations strongly off-centred in the oversized oxygen cages. Such disordered Mn displacements generate electric dipoles, which are proposed as the source of the observed dielectric relaxation. We show that in Mn-doped ceramics, the low-frequency polar TO1 mode softens on cooling and, at low temperatures, exhibits a higher frequency than in undoped KT. This mode displays no detectable splitting, which contrasts with Li-doped KT that also contains off-centred Li+ species on the cuboctahedral sites. Therefore, we conclude that the coupling between the Mn displacements and the lattice is weaker than in the Li case, and Mn-doped KT therefore exhibits a dielectric relaxation but no ferroelectric transition.

Dielectric Relaxation Studies of Silver Nanoparticles dispersed Liquid Crystal

2015 ◽  
Vol 8 (3) ◽  
pp. 2176-2188 ◽  
Author(s):  
Keisham Nanao Singh
Keyword(s):  
Activation Energy ◽  
Silver Nanoparticles ◽  
Liquid Crystal ◽  
Dielectric Relaxation ◽  
Relaxation Process ◽  
Relaxation Times ◽  
Low Frequency ◽  
Bulk Liquid ◽  
Molecular Rearrangement ◽  
Relaxation Studies

This article reports on the Dielectric Relaxation Studies of two Liquid Crystalline compounds - 7O.4 and 7O.6 - doped with dodecanethiol capped Silver Nanoparticles. The liquid crystal molecules are aligned homeotropically using CTAB. The low frequency relaxation process occurring above 1 MHz is fitted to Cole-Cole formula using the software Dielectric Spectra fit. The effect of the Silver Nanoparticles on the molecular dipole dynamics are discussed in terms of the fitted relaxation times, Cole-Cole distribution parameter and activation energy. The study indicate a local molecular rearrangement of the liquid crystal molecules without affecting the order of the bulk liquid crystal molecules but these local molecules surrounding the Silver Nanoparticles do not contribute to the relaxation process in the studied frequency range. The observed effect on activation energy suggests a change in interaction between the nanoparticles/liquid crystal molecules.

Dielectric Relaxation at Ultra Low Frequency

2003 ◽  
Vol 294 (1) ◽  
pp. 3-11
Author(s):  
E. R. Neagu ◽  
J. N. Marat-Mendes ◽  
C. J. Dias
Keyword(s):  
Dielectric Relaxation ◽  
Low Frequency

Low-frequency dielectric relaxation of hematite and silica sols

Langmuir ◽  
1993 ◽  
Vol 9 (7) ◽  
pp. 1625-1633 ◽  
Author(s):  
Johan Kijlstra ◽  
Herman P. van Leeuwen ◽  
Johannes Lyklema
Keyword(s):  
Dielectric Relaxation ◽  
Low Frequency ◽  
Silica Sols

Microstructure and dielectric relaxation of dipolar defects in Mn-doped (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystals

2013 ◽  
Vol 69 (5) ◽  
pp. 377-380 ◽  
Author(s):  
Xiaobing Li ◽  
Xiangyong Zhao ◽  
Bo Ren ◽  
Haosu Luo ◽  
Wenwei Ge ◽  
...  
Keyword(s):  
Dielectric Relaxation ◽  
Single Crystals ◽  
Mn Doped

Hopping conduction in Mn-doped ZnO

2003 ◽  
Vol 82 (1) ◽  
pp. 67-69 ◽  
Author(s):  
Jiaping Han ◽  
Mingrong Shen ◽  
Wenwu Cao ◽  
A. M. R. Senos ◽  
P. Q. Mantas
Keyword(s):  
Hopping Conduction ◽  
Doped Zno ◽  
Mn Doped

Low-frequency dielectric relaxation in columnar hexagonal and micellar inverse cubic mesophases

1997 ◽  
Vol 23 (6) ◽  
pp. 891-896 ◽  
Author(s):  
H. KRESSE ◽  
H. SCHMALFUSS ◽  
B. GESTBLOM ◽  
K. BORISCH ◽  
C. TSCHIERSKE
Keyword(s):  
Dielectric Relaxation ◽  
Low Frequency
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