Mq. Huang et We. Wallace, STRUCTURE AND MAGNETIC-PROPERTIES OF RFE13-XSIX (R = PR, ND OR GD, X = 2.5-5), Journal of magnetism and magnetic materials, 173(3), 1997, pp. 225-229
RFe13-xSix (R = Pr, Nd and Gd) alloys with x = 2.5-5 have been synthes
ized and characterized in a magnetic held up to 17 kOe and in a temper
ature range 10-1173 K to ascertain whether they might be useful as hig
h temperature, high-energy permanent magnet materials. It was found th
at a body-centered tetragonal (BCT) Ce2Ni17Si9-type structure forms in
PrFe13-xSix alloys when x greater than or equal to 4. The Curie tempe
ratures T-c of this BCT phase are in a range 50-90 K, higher than that
of the corresponding PrCo13-xSix BCT phase (similar to 20 K). The PrF
e13-xSix alloys with x greater than or equal to 4 show spin reorientat
ion at cryogenic temperatures (15-47 K) and exhibit significant coerci
vity in loose powder samples below their spin-reorientation temperatur
e. Using the information about the magnetization of LaFe13-xSix BCT al
loys, one can estimate the moment of Pr ion in PrFe13-xSix alloys, It
is found to be very close to that in PrCo13-xSix BCT alloys, around 2
mu(B)/atom. For R = Nd or Gd, the RFe13-xSix alloys occur only as mixt
ures of RFe2Si2, R(Fe,Si)(11) and Fe-Si. The Ce2Ni17Si9-type structure
cannot be formed in these alloys even when x = 5. The low T-c for the
PrFe13-xSix alloys precludes their use as a permanent magnet material
, except perhaps at low temperature.