TY  - JOUR
AU  - Tegel, M.
AU  - Hummel, F.
AU  - Su, Y.
AU  - Chatterji, T.
AU  - Brunelli, M.
AU  - Johrendt, D.
TI  - Non-stoichometry and the magnetic structure of Sr2CrO3FeAs
JO  - epl
VL  - 89
SN  - 0302-072X
CY  - Les Ulis
PB  - EDP Sciences
M1  - PreJuSER-8899
SP  - 37006
PY  - 2010
N1  - This work was financially supported by the German Research Foundation (DFG). MT would like to thank Dr K. ROMER for financial support.
AB  - The iron arsenide Sr2CrO3FeAs with the tetragonal Sr2GaO3CuS-type structure was synthesized and its crystal structure re-determined by neutron powder diffraction. In contrast to previous X-ray crystallographic studies, a mixed occupancy of chromium and iron was found within the FeAs4/4 layer (93 +/- 1%Fe : 7 +/- 1%Cr). We suggest that the partial Cr-doping at the Fe site is the reason for the absence of a spin-density-wave anomaly and superconductivity in this compound. Additional experiments via neutron polarization analysis revealed short-range spin correlations below similar to 100 K and long-range antiferromagnetic ordering below T-N = 36 K with a magnetic propagation vector of q = (1/2, 1/2, 0). The Cr3+ -ions form a collinear magnetic structure of the C-type in the magnetic space group C(P)mma' (a' = a-b, b' = a+b, c' = c), where Cr3+-ions occupy the 4g (0, 1/4, z) Wyckoff position. The magnetic moments are aligned along the orthorhombic a'-axis. At 3.5 K, an ordered magnetic moment of 2.75 +/- 0.05 mu B for the Cr3+ -sublattice was refined.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000274848600020
DO  - DOI:10.1209/0295-5075/89/37006
UR  - https://juser.fz-juelich.de/record/8899
ER  -