Vmt. Thiede et al., PREPARATION, CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF THE INTERMETALLIC COMPOUNDS LN(7-DR, LU)(X)RE(12)AL(61+Y) (LN=Y, GD), Journal of alloys and compounds, 261(1-2), 1997, pp. 54-61
The compounds Ln(7+x)Re(12)Al(61+y) (Ln=Gd, Tb, Dy, Lu) have been prep
ared for the first time. They crystallize with the hexagonal Y7.28Re12
Al61.38 type structure (P6(3)/mcm, Z=1), which was refined for three r
epresentatives from single-crystal X-ray data to residuals of less tha
n 2%, yielding the compositions Gd7.23Re12Al61.70, Dy7.50Re12Al61.02 a
nd Lu7.61Re12Al61.02. The differences in the compositions result from
the variable occupancy of three crystallographic sites located on the
hexagonal axis at 0, 0, z. The compositions correlate with the atomic
size of the rare earth components. The magnetic properties of several
compounds have been determined with a SQUID magnetometer in the temper
ature range from 2 to 300 K with magnetic flux densities up to 5.5 T.Y
7.28Re12Al61.38 is Pauli paramagnetic, indicating that the rhenium ato
ms in these isotypic compounds do not carry magnetic moments. The beha
viour of the other compounds is dominated by the magnetic properties o
f the rare earth components. Gd7.23Re12Al61.70 is antiferromagnetic. T
he terbium compound is metamagnetic. Dy7.50Re12Al61.17 and the earlier
reported compounds Ho7.32Re12Al61.48 and Er7+xRe12Al61+y are ferromag
netic. The magnetic ordering temperatures are all lower than 15 K. (C)
1997 Elsevier Science S.A.