Al4(Cr,Fe): A Structure Survey
A single crystal of Al4(Cr,Fe) grown by the Czochralski method has been investigated using X-ray and also neutron diffraction. The average structure of this crystal with a composition of Al79.1Cr17.8Fe3.1 was found to be body-centered orthorhombic with the space group Immm. Using neutrons it was possible to distinguish the Fe and Cr positions within the structure. However, the diffraction patterns of both, X-ray as well as neutrons, showed additional reflections beyond the Bragg reflections violating the body-centering and reducing the space group symmetry to Pmm2. A renewed structure analysis taking also these additional reflections into account exhibits significant changes of about 30 % of the atomic positions. Features related to extra diffraction phenomena beyond the Bragg reflections are discussed in some detail.
KeywordsNeutron Diffraction Bragg Reflection Czochralski Method Superlattice Reflection Neutron Data
The authors would like to thank Dr. Sandra Altmannshofer for providing the X-ray data set.
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