scholarly journals Polaronic behavior of La0.8Te0.2MnO3

2013 ◽  
Vol 03 (04) ◽  
pp. 1320002
Author(s):  
Cene Filipič ◽  
Adrijan Levstik
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Theoretical Model ◽  
Charge Transport ◽  
Detailed Analysis ◽  
Dielectric Response ◽  
Charge Carriers ◽  
Published Data ◽  
Ac Electrical Conductivity ◽  
Small Polarons

We have analyzed recently published data of the ac electrical conductivity and dielectric constant in La 0.8 Te 0.2 MnO 3 (LTMO), and at temperatures below 500 K both quantities follow the universal dielectric response (UDR) typical of hopping or tunneling of localized charge carriers. A detailed analysis of the temperature dependence of the UDR parameter s in terms of the theoretical model for tunneling of small polarons revealed that below 500 K, this mechanism governs the charge transport in LTMO system.

scholarly journals Femtosecond tunneling of polarons in Pb5Cr3F19

2014 ◽  
Vol 04 (03) ◽  
pp. 1450020
Author(s):  
A. Levstik ◽  
C. Filipič ◽  
G. Tavčar ◽  
B. Žemva
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
Low Temperatures ◽  
Dielectric Response ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Charge Carriers ◽  
Complex Dielectric Constant ◽  
Ac Electrical Conductivity ◽  
Small Polarons

The complex dielectric constant/ac electrical conductivity was investigated as a function of frequency and temperature in Pb 5 Cr 3 F 19. The system undergoes a ferroelectric phase transition at higher temperatures. At lower temperatures the real part of the complex ac electric conductivity was found to follow the universal dielectric response (UDR) σ′ ∝ νs, typical for hopping or tunneling of localized charge carriers. A detailed analysis of the temperature dependence of the UDR parameter s in terms of the theoretical model for tunneling of small polarons revealed that, at low temperatures, this mechanism governs the charge transport in Pb 5 Cr 3 F 19. The value of the inverse attempt frequency τ0 indicates the femtosecond tunneling of polarons in the system similar to the Büttiker–Landauer transversal time.

scholarly journals Dependence of Electrical Properties on Frequency and Temperature for Novel Cyclopentenone Derivatives

2020 ◽  
Vol 1 (1) ◽  
pp. 13-25
Author(s):  
Salama A. H.
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Electrical Properties ◽  
Arrhenius Equation ◽  
Charge Carriers ◽  
Frequency Range ◽  
Ac Electrical Conductivity ◽  
Dc Electrical Conductivity ◽  
Arrhenius Relation

Electrical properties of some new cyclopentenone derivatives have been studied. The structures of prepared samples were characterized by (UV), (XRD) and (SEM). The dependence of electrical properties such as σdc , σac , ɛ' and ɛ'' on frequency and temperature were studied at frequency range from 50 Hz to 5 MHz and the temperature range from 25oC to 140oC. It was found that, ɛ' decreased with increasing frequency while it increases with increasing temperatures within the used ranges. Moreover, dielectric constant is structural dependent which is obvious from the variation of dielectric constant for each sample. Ac-electrical conductivity increased with increasing frequency which was attributed to the polarization of the charge carriers. The temperature dependence of dc-electrical conductivity show typical Arrhenius relation for the three prepared samples. The activation energy calculated from Arrhenius equation and the results are discussed in detailed.

scholarly journals Analysis of X-ray structure, dielectric properties and AC conductivity of (4E)-2-amino-3-cyanobenzo[b]oxocin-6-one

2016 ◽  
Vol 34 (2) ◽  
pp. 386-392 ◽  
Author(s):  
H.A.M. Ali ◽  
Magdy A. Ibrahim
Keyword(s):  
Crystal Structure ◽  
Activation Energy ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Relaxation Time ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Ac Electrical Conductivity ◽  
X Ray ◽  
Different Temperatures

AbstractThe crystal structure of (4E)-2-amino-3-cyanobenzo[b]oxocin-6-one, denoted as 4(E)-ACBO, was analyzed using X-ray diffraction technique. The dielectric and AC electrical conductivity measurements of the bulk 4(E)-ACBO in the form of pellet were studied in the range of frequency 42 Hz to 5 MHz and the temperature range of 303 K to 373 K. The temperature and frequency dependence of dielectric constant (∊1), dielectric loss (∊2) and AC electrical conductivity (σAC) were investigated. The relaxation time (τ) for electrons to hop over a barrier of height WH was calculated at different temperatures. The AC activation energy was determined from the temperature dependence of σAC at different frequencies.

Dielectric Response of Structured Multilayered Polyvinylidene Fluoride Films

2013 ◽  
Vol 721 ◽  
pp. 121-124
Author(s):  
Long Jiang ◽  
Qiong Fu ◽  
Wei Ping Li
Keyword(s):  
Dielectric Constant ◽  
Theoretical Model ◽  
Dielectric Property ◽  
Spin Coating ◽  
Dielectric Response ◽  
Polyvinylidene Fluoride ◽  
High Energy ◽  
Multilayer Films ◽  
Material Structure ◽  
Number Of Layers

To make clear the effect of thickness and layer number on the dielectric property of poly (vinylidenedi fluoride) (PVDF), the different multilayer films were prepared by spin coating. The relation between them has been explained by both experimental results and theoretical model. It is found the dielectric constant of multilayer increase linearly with the number of layers but decrease with the thickness. It is helpful to optimize the material structure and size parameters of polymer films for high energy capacitors.

scholarly journals Dielectric behavior and AC electrical conductivity analysis of PMMA films

2019 ◽  
Vol 11 (20) ◽  
pp. 47-57
Author(s):  
Bushra A. Hasan
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Casting Process ◽  
Intermolecular Forces ◽  
Dielectric Behavior ◽  
Ac Electrical Conductivity ◽  
Dielectric Constant And Loss ◽  
Conduction Behavior ◽  
Calculated Activation Energy

PMMA films of different thickness (0.006, 0.0105, 0.0206, 0.0385 and 0.056cm) were synthesized by casting process. The temperature and frequency dependence of dielectric constant and AC electrical conductivity measurements at various frequencies (10kHz-10MHz) and temperatures (293-373K) were carried out. Few anomalies in dielectric studies were observed near 313 and 373 K respectively. These points were related to glass transitions temperature. The variation of activation energy and conduction behavior was studied .From the AC conduction studies, it is confirmed that the mechanism responsible for the conduction process is hopping of carriers. The variations of the dielectric constant and loss as function of frequency at different temperature was observed and the results were discussed. The calculated activation energy varied with the thickness, temperature, and applied frequency. Conductivity plots against frequency suggested that the response obeying the universal power law concerning the AC conductivity and dielectric behavior of polymer. The polarizability a increases with temperature but decreases with thickness indicating weekends and rising of intermolecular forces respectively.

scholarly journals Structural and Dielectric Properties of (1-x) (Al0.2La0.8TiO3) + (x) (BiZnFeO3) (x = 0.2 - 0.8) Nanocomposites

2021 ◽  
Author(s):  
A. Mallikarjuna ◽  
N. Suresh Kumar ◽  
T. Anil Babu ◽  
S. Ramesh ◽  
Chandra Babu Naidu K
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Phase Transformation ◽  
Dielectric Properties ◽  
Dielectric Behavior ◽  
Perfect Absorber ◽  
X Ray Diffraction ◽  
Ac Electrical Conductivity ◽  
X Ray ◽  
Diffraction Patterns

Abstract (1-x) (Al0.2La0.8TiO3) + (x) (BiZnFeO3) (x = 0.2 - 0.8) [ALTBZFO] nanocomposites were synthesized via hydrothermal method. The X-ray diffraction patterns indicated the phase transformation from tetragonal to cubic for x = 0.2 to 0.4 - 0.8 samples, respectively. The surface morphology showed the existence of nanospheres like structures. At 1 MHz frequency also, the dielectric constant was increased from 230 to 710 for x = 0.2 – 0.6 samples, respectively. But, interestingly, x = 0.6 nanocomposite exhibited the negative dielectric behavior having the dielectric constant (ε') ~ -58.5 and dielectric loss (ε") ~ -417 at 8 MHz. Likewise, x = 0.6 sample showed ac-electrical conductivity (σac) -0.159 S/cm at 6 MHz. Hence, these kinds of materials can provide high charge stored capacitor, and perfect absorber applications.

Percolation properties of cellular composite systems

2001 ◽  
Vol 699 ◽  
Author(s):  
C. Chiteme ◽  
D.S. McLachlan
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Cellular Structure ◽  
Flicker Noise ◽  
Power Laws ◽  
Phenomenological Equation ◽  
Ac Electrical Conductivity ◽  
Composite Systems ◽  
Cellular Composite ◽  
Percolation Phenomena

Percolation phenomena were studied in a series of six composites with a cellular structure. Measurements made on the composites include dc and ac electrical conductivity, dielectric constant, 1/for flicker noise and magnetoresistance. Results arising from these extensive measurements were fitted to the percolation power laws and a phenomenological equation to give various exponents, which are presented, discussed and compared.

Defect Chemistry of “BaCuO2” II. Transport Properties and Nature of Defects

1995 ◽  
Vol 50 (11) ◽  
pp. 1059-1066 ◽  
Author(s):  
G. Chiodelli ◽  
U. Anselmi-Tamburini ◽  
M. Arimondi ◽  
G. Spinolo ◽  
G. Flor
Keyword(s):  
Electrical Conductivity ◽  
Charge Transport ◽  
Transport Properties ◽  
Carrier Mobility ◽  
Transport Number ◽  
Ionic Transport ◽  
Ionic Transport Number ◽  
Wide Range ◽  
Small Polarons ◽  
Cation Ratio

Abstract The charge transport properties of "BaCuO2" with 88:90 (Ba :Cu) cation ratio were characterized by thermopower, electrical conductivity and ionic transport number measurements in a wide range of temperature and oxygen partial pressure conditions. The nature of carriers is always represented by small polarons due to self-trapping of the electronic holes generated by the oxygen non-stoichiometry equilibrium. Some anomalies in carrier mobility as a function of temperature are shown not to be related to incomplete ionization of oxygen atoms on interstitial sites

scholarly journals Investigation of dielectric properties of heterostructures based on ZnO structures

2018 ◽  
Vol 35 (4) ◽  
pp. 885-892
Author(s):  
A.H. Selçuk ◽  
E. Orhan ◽  
S. Bilge Ocak ◽  
A.B. Selçuk ◽  
U. Gökmen
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Frequency Dependence ◽  
Loss Tangent ◽  
Electrical Modulus ◽  
Ac Electrical Conductivity

Abstract The voltage and frequency dependence of dielectric constant є′, dielectric loss є″, electrical modulus M″, M′, loss tangent tanδ and AC electrical conductivity σAC of p-Si/ZnO/PMMA/Al, p-Si/ZnO/Al and p-Si/PMMA/Al structures have been investigated by means of experimental G-V and C-V measurements at 30 kHz, 100kHz, 500 kHz and 1 MHz in this work. While the values of є′, є″, tanδ and σAC decreased, the values of M′ and M″ increased for these structures when frequency was increased and those of p-Si/ZnO/Al and p-Si/PMMA/Al were comparable with those of p-Si/ZnO/PMMA/Al. The obtained results showed that the values of p-Si/ZnO/PMMA/Al structure were lower than the values of p-Si/ZnO/Al and p-Si/PMMA/Al.

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