Investigation of pressure dependence of electrical resistivity based on mean-field approximation in Gd-element

Abstract

Eigenvalue calculations were performed on the mechanism of electro-magnetic coupling in order to evaluate the effective exchange Jij in the induced negative exchange potential in Gd by which the emergence of the Kondo-like character around TC by low pressure is possible. Since the two subsystems, i.e. “local spin exchange” and “conduction band”, are competently separated in Gd, the response of both systems to the pressure is investigated in the range of θP/TC. First, the mechanism of mean field approximation through the conduction electron can be manifested by ρ(T) and second, the challenging effect could be characterized by local dynamic distortion that is appeared to change appreciably at the onset of magnetic phase transition. The calculations were based on the molecular field approximation in order to consider the effect of sign and strength of exchange interaction for different reciprocal lattice directions and for various correlation lengths RC=2KFRij. Validity of this model was evaluated by means of electrical resistivity measurement for this element, in which the mechanism of coupling between Gd and the conduction electron is more evident in the generation of a minimum character in the electrical resistivity, which shifts toward higher values by a low static pressure. The experimental and theoretical results were in good agreement with the available previous data.