Reduced Magneto-Resistivity of a Rare-Earth Crystalline and the Degeneracy Removals of Its Crystal-Field Levels

A theoretical approach is generalized and employed to calculate the magneto-resistivity of a rare-earth crystalline (CeAl₂) with degenerate ground crystal-field (CF) level in the presence of external fields. The calculated results show that when a magnetic field is applied in the c-direction, the magneto-resistivity may be reduced by more than 90% in certain cases in comparison with the pure CF contribution at the same temperature, demonstrating the strong effects of the degeneracy removals of the CF levels on the magnetic resistivity.