Temperature Dependence of Dielectric Constants of Cubic Ionic Compounds

Surface Plasmon Resonance Tunability in Au−VO2 Thermochromic Nano-composites

“…This host matrix consisting of Vanadium Dioxide VO 2 , undergoes a semiconducting-metallic transition when the temperature is raised above the critical value of T c Ϸ68°C, with a jump-like change of the electric conductivity by several orders of magnitude. This thermally driven first order phase transition of the host VO 2 concurs with a crystallographic phase transition from monoclinic to tetragonal and is accompanied by a strong variation in electric, magnetic and specific heat properties (38)(39)(40)(41)(42)(43). This semiconductormetal phase transition is followed naturally by a sharp optical transition and therefore a variation of the optical constants: the real and imaginary parts of the refractive index n*(T)= n(T) + j k(T).…”

“…The temperature and frequency dependence of the imaginary part of the index of refraction, k(T, ), (Index of extinction), is more involved and requires consideration of not only the dominant physical processes but also higher order processes, impurities and defects. The temperature dependence of the refractive index n*(T, ) = n(T, ) -j k(T, ) could be estimated using the LorentzLorenz formula (38):…”

Relationship between tolerance factor and temperature coefficient of permittivity of temperature-stable high permittivity BaTiO3–Bi(Me)O3 compounds

“…This finding suggests that both groups of materials share a common relationship between the TC" and the tolerance factor. The temperature dependence of the permittivity of (Ba/Sr)(Me 1=3 (Nb/Ta) 2=3 ÞO 3 microwave dielectrics and other cubic compounds was explained by Colla et al, 27 Bosman and Havinga, 28 Cockbain and Harrop, 29 and Harrop. 30 The analysis of the macroscopic Clausius-Mossotti formula with respect to temperature showed that three physical processes contribute to the temperature dependence of permittivity in cubic compounds.…”

Nonlinear dielectric microwave losses in MgO substrates

“…, with ε r ∼9.8 and ε ∞ ∼3 the permittivities for MgO at low and optical frequencies [18,25]. The relaxation time τ d increases for decreasing temperatures, leading to an increase of tanδ in the range ωτ d <1.…”