Abrupt symmetry decrease in the ThT2Al20 alloys (T=3d transition metal)

作者：Uziel A; Bram A I; Venkert A; Kiv A E; Fuks D; Meshi L^*

来源：Journal of Alloys and Compounds, 2015, 648: 353-359.

DOI：10.1016/j.jallcom.2015.06.216

• Aluminide
• Ternary alloys
• Crystal structure
• DFT

Th-T-Al system, where T-3d transition metals, was studied at ThT2Al20 stoichiometry to establish the influence of T on the structural stability of ternary aluminide formed. Different alloys were prepared, varying T in the row from Ti to Fe. Using electron microscopy and X-ray diffraction methods it was found that ThT2Al20 phase adopts CeCr2Al20 structure type when T = Ti, V, and Cr. Starting from Mn, the symmetry of the stable Al-rich phase, which forms in the alloys with the same composition, decreases from cubic to orthorhombic. The results of Density Functional Theory (DFT) calculations coincide with experiments. Concepts of the Theory of Coordination Compounds and Jahne-Teller effect were used to explain the observed abrupt change of the symmetry. These considerations were supported by DFT calculations.

• 出版日期2015-11-5