On a possible mechanism for R-phase formation in TiNi
E V Savushkin; V B Lapin; V E Egorushkin; E V Savushkin; Dept. of Appl. Phys., Inst. for Metal Phys., Acad. of Sci., Sumy, Ukrainian SSR, USSR; V B Lapin; Dept. of Appl. Phys., Inst. for Metal Phys., Acad. of Sci., Sumy, Ukrainian SSR, USSR; V E Egorushkin; Dept. of Appl. Phys., Inst. for Metal Phys., Acad. of Sci., Sumy, Ukrainian SSR, USSR
Журнал:
Journal of Physics: Condensed Matter
Дата:
1991-11-18
Аннотация:
The multi-atom per unit cell average t-matrix approximation is used to study evolution of the Ti(Ni<sub>1-x</sub>Fe<sub>x</sub>) and Ti(Ni<sub>1-x</sub>Pd<sub>x</sub>) Fermi surfaces, as the concentration x is increased. The possible relation of the Fermi surface peculiarities with the B-R martensitic transformation in these alloys is discussed. It is theoretically shown that the appearance of the charge-density wave with wavevector Q<sub>1</sub>=2/3 pi (1, 1, 1) in the presence of a rhombic distortion can be caused by softening of the phonon mode with wavevector Q<sub>2</sub>=2/3 pi (1, 1, 0). On this basis a new microscopic mechanism for the R-phase formation in TiNi is proposed.
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