Suppression of p-f mixing and formation of a superzone gap in CeSbNix

We report electrical resistivity, Hall coefficient, magnetic susceptibility , magnetization, and magnetoresistance measurements on CeSbNix (0 less than or equal tox less than or equal to0.4), where the Ni atoms are incorporate d interstitially into the cubic cell of CeSb. The Neel temperature T-N drop s from 16 K for x=0 to 9 K for x=0.05 and then gradually increases to 12.5 K for x=0.4. The initial depression of both T-N and saturation moment is as cribed to the collapse of p-f mixing by the decrease of the 5p-hofe concent ration in the semimetallic CeSb. The resistivity for x greater than or equa l to0.08 shows a sharp rise just below T-N, which is quenched by the applic ation of magnetic fields higher than the metamagnetic transition field. Thi s finding indicates that a superzone gap is formed in the 5d-electron band of CeSbNix for x greater than or equal to0.08 as a result of the type-I ant iferromagnetic order.