MAGNETIC AND STRUCTURAL CHARACTERISTICS OF RCO9-SI4 ALLOYS (R=PR OR GD, DELTA=0-4)(DELTA)

Studies of the magnetic and structural characteristics of RCo9+deltaSi 4 (delta=0-4), nonstoichiometric alloys, have been extended from R=La in our earlier work to R=Pr and Gd. In the present work, as the extra Co content increases, the magnetic properties M, T-c, and H-c are sign ificantly enhanced compared to that of the stoichiometric alloys (delt a=0). Using x-ray diffraction measurements, the sublattice occupancies are calculated. The extra Co atoms are found to occupy the 4a and 16L (2) sites in the Ce2Ni17Si9 unit cell. They partially replace R and Si in these sites. (C) 1997 American Institute of Physics.