Crystal structures, unusual magnetic properties and electronic band structures of Cr{sub 5-x}Ti{sub x}Te{sub 8}
- Institute of Inorganic Chemistry, Christian-Albrechts-University Kiel, Olshausenstr. 40, D-24098 Kiel (Germany)
- Department of Chemistry, LMU-Munich, Butenandstr. 5-13, D-81377 Munich (Germany)
The effect of substitution of the cation Cr by Ti in Cr{sub 5}Te{sub 8} has been investigated with respect to its crystal structure, magnetic properties, and electronic structure. The compounds Cr{sub 5-x}Ti{sub x}Te{sub 8} (x=0, 0.5, 1, 1.5, 1.85, 2, 3, 4, 5) were synthesized at elevated temperatures followed by slow cooling the samples to room temperature. The crystal structures have been refined with X-ray powder diffraction data with the Rietveld method. Three structural modifications are identified: monoclinic with space group F2/m for Cr{sub 5-x}Ti{sub x}Te{sub 8} (x=0, 0.5, 1, 1.5, 1.85), trigonal supercell with space group P-3m1 for Cr{sub 5-x}Ti{sub x}Te{sub 8} (x=2, 3), and trigonal basic cell with space group P-3m1 for Cr{sub 5-x}Ti{sub x}Te{sub 8} (x=4, 5). The structures of all these phases are related to the NiAs structure with full and deficient metal layers stacking alternatively along the c-axis. The irreversibility in the field-cooled/zero-field-cooled magnetization with low field depends strongly on the Ti concentration x. Four types of magnetic states are distinguished: re-entrant ferromagnet for m-Cr{sub 5}Te{sub 8}, cluster-glass for m-Cr{sub 4.5}Ti{sub 0.5}Te{sub 8} and m-Cr{sub 4}TiTe{sub 8}, antiferromagnetic for m-Cr{sub 3.5}Ti{sub 1.5}Te{sub 8}, and spin-glass for tr-Cr{sub 3}Ti{sub 2}Te{sub 8}, tr-Cr{sub 2}Ti{sub 3}Te{sub 8}, and Cr{sub 0.25}TiTe{sub 2}. Accompanying spin polarized scalar-relativistic Korringa-Kohn-Rostoker band-structure calculations strongly support the observation that the crystallographic sites in the full metal layers are preferentially occupied and predict that Ti atoms have the preference to occupy the full metal layers. These compounds are predicted metallic. Results for the spin-resolved DOS and magnetic moments on each crystallographic sites are presented.
- OSTI ID:
- 20729085
- Journal Information:
- Journal of Solid State Chemistry, Vol. 178, Issue 9; Other Information: DOI: 10.1016/j.jssc.2005.06.004; PII: S0022-4596(05)00251-3; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANTIFERROMAGNETISM
CATIONS
CHROMIUM TELLURIDES
CRYSTALLOGRAPHY
ELECTRONIC STRUCTURE
GLASS
LAYERS
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MAGNETIZATION
MONOCLINIC LATTICES
SPACE GROUPS
SPIN GLASS STATE
SPIN ORIENTATION
TEMPERATURE RANGE 0273-0400 K
X-RAY DIFFRACTION