Xf. Han et al., SYNTHESIS AND MAGNETIC-PROPERTIES OF NOVEL COMPOUNDS R-3(FE,T)(29) (R=Y, CE, ND, SM, GD, TB, AND DY - T=V AND CR), Journal of applied physics, 81(11), 1997, pp. 7450-7457
A systematic investigation of structure and intrinsic magnetic propert
ies of the novel compounds R-3(Fe,T)(29) (R = Y, Ce, Nd, Sm, Gd, Tb, a
nd Dy; T = V and Cr) has been performed. The lattice constants and uni
t cell volume decrease with increasing the rare-earth atomic number fr
om R = Nd to Dy, except for Ce, reflecting the lanthanide contraction.
The Curie temperature increases from R = Ce to Gd and decreases from
Gd to Dy, respectively, with increasing atomic number and Gd3Fe29-xTx
has the highest Curie temperature for each series of R3Fe29-xTx (T = V
or Cr) compounds. The saturation magnetization of R3Fe29-xTx at 4.2 K
decreases gradually from R = Nd to Dy with increasing atomic number,
except for Ce, in each series of R3Fe29-xTx. It is suggested that the
Ce ion in Ce3Fe29-xTx valence fluctuated which leads to the unusual ma
gnetic properties. The spin reorientations of the easy magnetization d
irection of R3Fe29-xTx are observed at around 230, 230; and 160 K for
R = Nd, Sm, and Tb when T = V, and at around 230 and 180 K for R = Nd
and Tb when T = Cr, respectively. First order magnetization processes
are observed around 5.7 T for Sm3Fe26.7V2.3 and 4 T for Sm3Fe24.0Cr5.0
at 4.2 K, 2.0 T for Tb3Fe28.0V1.0, and 2.3 T for Tb3Fe28.0Cr1.0 at ro
om temperature. A phenomenological analysis shows that the saturation
magnetization of R3Fe29-xTx compounds with a low T concentration can b
e roughly calculated based on a combination of those of the 2:17R and
1:12 units in a ratio of 1:1. (C) 1997 American Institute of Physics.