Magnetoresistance Due to Ce Impurities in Metals

Abstract

In order to calculate magnetoresistances due to the Ce impurities coupled with conduction electrons by the s-f exchange interaction, conditions for determining the number of local conduction electrons around Ce are given, which are valid for arbitrary spin-orbit and crystal-field splittings of Ce ion. General arguments for resistivity and magnetoresistance are given. In order to discuss the resistivities and magnetoresistances of the dense Kondo Ce compounds quantitatively, we adopt the Yosida theory and carry out the wave number integration numerically. It is shown that the resistivity along the crystal c-axis becomes small for crystalline fields with tetragonal or hexagonal symmetry and that a peak of magnetoresistance is expected due to the Kondo effect re-enhancement.