Effect of cavity geometry on the performance of a gyrotron

Substitutional Effect on Dielectric Losses in Polycrystalline CaxSr1-xTiO3 and PbxSr1-xTiO3 Ferro-Electric Mixed Crystals

“…The influence on the anharmonic coupling coefficients in the Hamiltonian, being small is neglected. The modified Hamiltonian of a mixed displasive perovskite, in para-electric phase which includes defects (substitutional impurity),third and fourth order anharmonicity and higher order electric moment term are used in present study and is exactly similar as used earlier 20 is given H' = H + H D .…… (1) Where H is Hamiltonian for pure crystal and H D is the contribution by the defect in Hamiltonian which involves the effect of mass change and harmonic force constant change between the impurity and host lattice atoms due to substitutional defects. Where…”

“…… (10c) The notations used here are in the same sense as used by Yadav et al 20 and Naithani et al 21 . Temperature dependence of ν 2 (ω) can be written as ν 2 (ω)=− ( ) 2 + T+γ 2 T 2 +Δ ( ) …(11) Where Δ (ω) (shift in phonon frequency corresponds to pure crystal, Δ( (ω)) is temperature independent part due to defect and γ 1 and γ 2 are temperature dependent parts in ν 2 (ω) and depend on anharmonic force-constant and electric dipole moment terms.…”