THE MAGNETIC-PROPERTIES OF R(2)(FE1-XSIX)(17) COMPOUNDS (R=DY, Y)

The structures and magnetic properties of R(2)(Fe1-xSix)(17) compounds (R=Dy, Y) were investigated by x-ray phase analysis and magnetic meas urements. It is shown that Si substitution for Fe leads to a phase tra nsition at x=0.2, and that the mean iron magnetic moment mu(Fe) of R(2 )(Fe1-xSix)(17) compounds (R=Dy, Y) decreases as Si concentration x in creases; moreover, there is a maximum of dependence T-c(x) at about x= 0.16. It is found that the exchange interaction constant A(FeFe) in R( 2)(Fe1-xSix)(17) compounds (R=Dy, Y) increases with x increasing by me ans of mean-molecular-field analysis of T-c. (C) 1994 American Institu te of Physics.