Permeability Dispersion in Ni-Zn-Cu Ferrite and its Composite Materials

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• 作者：Dosoudil ; Rastislav ; U?¨¢kov¨¢ ; Marianna ; Sl¨¢ma ; Jozef ; Gruskov¨¢ ; Anna
• 刊名：Czechoslovak Journal of Physics
• 出版年：2004
• 出版时间：2004
• 年：2004
• 卷：54
• 期：4
• 页码：675-678
• 全文大小：356 KB

文摘

A model pseudopotential depending on an effective core radius but otherwise parameter free is used to study the interatomic interactions, phonon dispersion curves (in q and r-space analysis), phonon density of states, mode Grüneisen parameters, dynamical elastic constants (C₁₁, C₁₂ and C ₄₄), bulk modulus (B), shear modulus (C'), deviation from Cauchy relation (C₁₂−C₄₄), Poisson's ratio (σ), Young's modulus (Y), behavior of phonon frequencies in the elastic limit independent of the direction (Y₁), limiting value in the [110] direction (Y₂), degree of elastic anisotropy (A), maximum frequency &ohgr;_max, mean frequency ⟨&ohgr; ⟩, ⟨&ohgr;²⟩^1/2=(⟨&ohgr; ⟩/⟨&ohgr;^-1⟩)^1/2, fundamental frequency ⟨&ohgr;²⟩, and propagation velocities of the elastic constants in Cu, Ag, Au, Ni, Pd, and Pt. The contribution of s-like electrons is calculated in the second-order perturbation theory for the model potential while that of d-like electrons is taken into account by introducing repulsive short-range Born-Mayer like term. Very recently proposed screening function due to Sarkar et al. has been used to obtain the screened form factor. The theoretical results are compared with experimental findings wherever possible. A good agreement between theoretical investigations and experimental findings has proved the ability of our model potential for predicting a large number of physical properties of transition metals.