MAGNETIC AND MAGNETORESISTIVE PROPERTIES OF THE SERIES CE(NI1-XCOX)(2)B2C

Structural, magnetic, calorimetric and magnetoresistive studies on the solid solution Ce(Ni1-xCox)(2)B2C demonstrate that the Go-substitutio n decreases the unit-cell volume, the Sommerfeld constant gamma, and t he Pauli susceptibility chi(0). It increases the Debye temperature and the strength of the crystalline electric field. The structural modifi cation can be related to the variation of the tetrahedral angle subten ded by the B-(Ni,Co)-B bonds: a decrease in the tetrahedral angle cont racts the parameter a and elongates the length c and vice versa. The v ariation in the magnetic and electronic properties can be traced down to the shift of E-F (predominantly due to the less filling of the 3d-b and) away from the peak maximum of the density of state and the conseq uent reduction of N(E-F). The influence of the variation of the band f illing and the f-d hybridization on the magnetic behavior of CeT2B2C w ill be considered.