Cryst. Res. Technol. 36 2001 8-10 1119–1122
© WILEY- VCH Verlag Berlin GmbH, 13086 Berlin, 2001 0232-1300/01/8-1010-1119 $ 17.50+.50/0
Single crystals of the ScFe
4
Al
8
intermetallic compound were obtained by the Czochralski method from
a levitated melt. The X–ray powder diffraction, Laue and Berg–Barrett reflection topographies exhibit
that the obtained single crystals were a good quality. The lattice parameters a = 8.652 ± 0.004 Å, c =
5.020 ± 0.003 Å were calculated from powder diffraction patterns.
Keywords: intermetallic compound, single crystal growth, X-ray topography
(Received April 25, 2001; Accepted July 26, 2001)
1. Introduction
There is a large family of the tetragonal RT
x
M
12-x
compounds, where R is rare earth or
actinide element, with ThMn
12
type structure. These materials are formed in principle as
ternaries and they can be divided into two distinct subgroups: the first one with high
concentration of transition element T and the second one with lower concentration of T
ranging from x = 4 to 6. The representatives of the first group are potential interesting
magnetic materials, whereas the members of the second group, ScFe
4
Al
8
among them, exhibit
puzzling physical properties. For determination of physical properties one needs single
crystalline material.
The ThMn
12
-type tetragonal compounds existing mostly as ternaries or pseudoternaries
have caused recently a considerable interest both from the fundamental point of view (heavy
fermion-like compounds) and as potential hard magnetic materials (alloys with a high
concentration of Fe or Co) (for review, see SUSKI et al.). In the ThMn
12
-type of structure (the
space group I4/mmm) there are four inequivalent crystallographic positions: the 2(a) which
are occupied by the rare earth (Sc) or actinide atoms, whereas in the 8(f), 8(i) and 8(j) sites
other atoms are distributed. In the RFe
4
Al
8
-type compounds the iron atoms are located in
principle in the 8(f) position. These atoms form antiferromagnetic sublattice but the detailed
magnetic ordering exhibits various modifications even for nonmagnetic rare earths
(SCHOBINGER-PAPAMANTELLOS et al.). Sc like Y can be used as nonmagnetic component in
reference compounds to determine the contribution of the f-electron element to the
magnetism of intermetallics. ScFe
4
Al
8
is antiferromagnetic below about 120 K, following a
Curie-Weiss law at higher temperatures; however, at low temperature in magnetic field
above ~10 T it exhibits apparent saturation (KOTUR et al.). The temperature dependence of
the electrical resistivity shows a clear metallic character (KOTUR et al.). Therefore, to
elucidate the physical properties of this material a single crystal sample is indispensable. The
polycrystalline sample of ScFe
4
Al
8
has been obtained as described by KOTUR et al.
E. TALIK, A. WINIARSKI, B. KOTUR*, W. SUSKI**
Institute of Physics, University of Silesia, Katowice, Poland
*Ivan Franko National University of Lviv, Ukraine
**W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of
Sciences Wroclaw, Poland
Growth and X –Ray Characterization of ScFe
4
Al
8
Single
Crystals