STRUCTURE AND MAGNETIC-PROPERTIES OF LA1-XCEXFE10.4SI2.6 COMPOUNDS

The stability, crystal structure and magnetic properties of La1-xCexFe 13-ySiy have been investigated by x-ray powder diffraction and magneti c measurements. With increasing Ce content x, the solubility y of the Si and the stability of the NaZn13-type structure decrease. The crysta l structure of La0.4Ce0.6Fe10.4Si2.6 was refined by the Rietveld metho d. The refined result indicates that Si atoms preferentially occupy th e 96(i) positions in the NaZn13-type structure. The substitution of Ce for La in LaFe10.4Si2.6 results in a compression of the lattice cell volume and a decrease of the Curie temperature and the saturation magn etization. Taking the free ion value for the moment of the Ce3+ (mu(Ce 3+) = 2.1 mu(B)), the moment of the Fe atom was derived according to t he antiparallel coupling model. The calculated results indicate that t he moment of the Fe atom is weakly dependent on the value of x.