Dielectric Loss of Adsorbed Polar Molecules

1973 ◽  
Vol 51 (24) ◽  
pp. 4038-4047 ◽  
Author(s):  
T. McMullen
Keyword(s):  
Exact Solution ◽  
Dielectric Loss ◽  
Oscillator Model ◽  
Dielectric Susceptibility ◽  
Lattice Vibrations ◽  
Linear Coupling ◽  
Classical Oscillator ◽  
Ionic Solids ◽  
Density Of Phonon States ◽  
Diagrammatic Perturbation Theory

A theory of the dielectric susceptibility of polar gases adsorbed on ionic solids is presented. The rotational oscillator model of an adsorbed polar molecule is used, and dielectric loss is assumed to occur by phonon emission and absorption. For linear coupling of the rotational oscillator to the lattice vibrations, an exact solution is found using diagrammatic perturbation theory at finite temperature. In this model, appreciable loss is only found if the density of phonon states near the classical oscillator frequency is reasonably large, and it is suggested that this is to be expected in situations where the rotational oscillator model is valid. The method can be extended to more complex adsorbate–lattice interactions.

AC Loss Modeling in Ba0.5Sr0.5TiO3 Using Dielectric Relaxation

2004 ◽  
Vol 833 ◽  
Author(s):  
Nadia K. Pervez ◽  
Jiwei Lu ◽  
Susanne Stemmer ◽  
Robert A. York
Keyword(s):  
Dielectric Loss ◽  
Dielectric Relaxation ◽  
Power Law ◽  
Fractional Power ◽  
Ac Loss ◽  
Dielectric Susceptibility ◽  
Network Analyzer ◽  
Q Factor ◽  
Relaxation Model ◽  
Q Factors

ABSTRACTIn universal relaxation, a material's complex dielectric susceptibility follows a fractional power law f1-n where 0 < n < 1 over multiple decades of frequency. In a variety of materials, including Ba0.5Sr0.5Ti03, dielectric relaxation has been observed to follow this universal relaxation model with values of n close to 1. In this work we have shown that the universal relaxation model can be used to calculate dielectric loss even when n is very close to 1. Our calculated Q-factors agree with measured values at 1 MHz; this agreement suggests that this technique may be used for higher frequencies where network analyzer measurements and electrode parasitics complicate Q-factor determination.

On the thermal ionization of trapped electrons in ionic solids

1955 ◽  
Vol 231 (1186) ◽  
pp. 308-320 ◽  
Keyword(s):  
Ground State ◽  
High Frequency ◽  
Ionic Crystal ◽  
Dielectric Constants ◽  
Variation Method ◽  
Lattice Vibrations ◽  
Appreciable Difference ◽  
Ionic Solids ◽  
Self Consistent ◽  
Consistent Method

The ground state of an electron trapped at a defect of the interstitial ion type in an ionic crystal is determined by a variation method in which the interaction between electron and lattice vibrations is treated on a dynamic basis. The results are com pared with static calculations using a self-consistent method, and it is shown that for certain ranges of the low- and high-frequency dielectric constants an appreciable difference in energy may occur.

Polarization Dynamics in La5/3Sr1/3NiO4

1999 ◽  
Vol 602 ◽  
Author(s):  
N. Hakim ◽  
Z. Zhai ◽  
C. Kusko ◽  
P.V. Parimi ◽  
S-W. Cheong ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Dielectric Response ◽  
Charge Ordering ◽  
Dielectric Susceptibility ◽  
Dynamic Susceptibility ◽  
Loss Peak ◽  
Relaxation Rates ◽  
Relaxation Mode ◽  
Microwave Frequencies ◽  
Charge Stripe

AbstractDynamic susceptibility measurements at microwave frequencies (2 – 10GHz) are a sensitive probe of charge dynamcis in La5/3Sr1/3NiO4. Below the charge ordering temperature of 240K, a dielectric loss peak due to a relaxation mode with a large dielectric susceptibility is observed, and is associated with charge stripe formation. The dielectric response for Hω∥b (Eω ⊥ b) is well represented by ε(T) = εo/(1 – iωτ(T)), with εo, ∼ 50, and τ(T) = 2 × 10−9(sec) exp(−T/37K). Parallel conductivity σ(T) contributions dominate at higher temperatures and for Hω∥c (Eω ⊥ c). The dielectric loss peak observed indicates that the charge relaxation rates lie in the GHz frequency ranges.

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