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Representing the heavy fermion systems by the Periodic Anderson Model (PAM), we have used Zubarev technique to study the temperature dependence of resistivity. The resistivity calculated shows the general features experimentally observed in these materials. Further, we have shown how the strength of hybridization as well as the position of the f-level affects the electrical resistivity and Kondo temperature of these systems. [ABSTRACT FROM AUTHOR]

Here, we have studied theoretically the temperature dependence of magnetic susceptibility of some heavy fermion (HF) superconductors through Fulde model. It is observed that, the calculated magnetic susceptibility show correct behaviour as a function of temperature with existing experimental results for some U-based and Ce-based HF superconductors. The extrapolated Kondo temperature for UPt3 found to give nearly the same value as observed experimentally by Frings et al (1983). [ABSTRACT FROM AUTHOR]

Here, we have analyzed the electron-phonon interaction in the Periodic Anderson Model (PAM) to describe the temperature dependence of resistivity in some heavy fermion (HF) systems for finite wave vector (q ) and for finite temperature (T). Since the resistivity is related to the imaginary part of the electron self energy, the expression for the same is evaluated through double time temperature dependant Green function technique of the Zubarev type. The effect of different system parameters namely the position of 4f level, E0 and the electron - phonon coupling strengths on resistivity have been studied. The results obtained give satisfactory explanations to the experimental observations. [ABSTRACT FROM AUTHOR]

A theoretical explanation is provided to understand the effect of impurity on the electron-phonon interaction in some alloyed Heavy Fermion (HF) systems in the normal state on the basis of Periodic Anderson Model (PAM). Two different mechanisms of the electron-phonon interaction, namely, the usual interaction between the Phonons with both the f-electrons as well as with the hybridization of conduction and f-electrons are considered. It is assumed that the impurities perturb the host crystal because of the difference in mass, the change in nearest neighbor force constant and the local modification of the electron-phonon interaction. The phonon self-energy due to these perturbations is calculated to the lowest order of the impurity concentration. The phonon response functions are evaluated for all wave vector q and temperature T in the mean field approximation. To avoid complications numerical evaluations are made for long wave length in the static limit. The influence of impurity mass parameter on other system parameters like position of f-level, the effective coupling strength on calculated phonon frequency is studied. [ABSTRACT FROM AUTHOR]