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Current issue   Ukr. J. Phys. 2017, Vol. 62, N 2, p.106-111
https://doi.org/10.15407/ujpe62.02.0106    Paper

Uvarov V.N.1, Uvarov N.V.1, Bespalov S.A.2, Nemoshkalenko M.V.1

1 G.V. Kurdyumov Institute for Metal Physics, Nat. Acad. of Sci. of Ukraine
(36 Vernadskyi Ave., Kyiv 03142, Ukraine; e-mail: uvarov@imp.kiev.ua)
2 Presidium of the NAS of Ukraine
(54 Volodymyrs’ka Str., Kyiv 01601, Ukraine)

Atomic Disordering and Electron Band Structure in the Heusler Alloy CoTiSb

Section: Atoms and Molecules
Original Author's Text: Ukrainian

Abstract:  With the help of the Linearized Augmented Plane Wave (LAPW) method, the role of some structural types of CoTiSb alloy in the formation of its energy, spatial, spectral, and spin characteristics has been clarifed. The ground state of CoTiSb alloy, which is characterized by the highest cohesive energy, is found to be realized in the case where atoms and vacancies are arranged like in the C1ba phase. Transitions to the L2ac and B2c phases with diferent arrangements of alloy components in their crystal lattices are accompanied by the emergence of high-energy metastable states. CoTiSb alloy in the ground state is a nonmagnetic insulator. The metastable phases transform into metals with spin-polarized electron states and magnetic moments mainly localized at cobalt atoms.

Key words: band structure calculations, X-ray electron spectra, spintronics.

References:

  1. R.I. Krypyakevich, V.Ya. Markiv. Crystal structures of ternary compound in the systems Ti(V)–Fe(Co, Ni)–Sn(Sb). Dopov. Akad. Nauk UkrRSR No. 12, 1606 (1963) (in Ukrainian).
  2. T. Graf, C. Felser, S.S.P. Parkin. Simple rules for the understanding of Heusler compounds. Prog. Solid State Chem. 39, 1 (2011).
     CrossRef
  3. G.E. Bacon, J.S. Plant. Chemical ordering in Heusler alloys with the general formula A2BC or ABC. J. Phys. F 1, 524 (1971).
     CrossRef
  4. S. Ishida, T. Masaki, S. Fujii, S. Asano. Theoretical predicts of half-metallic compounds with the C1 structure. Physica B 239, 163 (1997).
     CrossRef
  5. J. Tobola, L. Jodin, P. Pecheur, G. Venturini. Unusual electron structure and electron transport properties of some disordered half-Heusler phases. J. Alloy. Compd. 383, 328 (2004).
     CrossRef
  6. P. Larson, S.D. Mahanti, M.G. Kanatzidis. Structural stability of Ni-containing half-Heusler compounds. Phys. Rev. B 62, 12754 (2000).
     CrossRef
  7. T. Sekimoto, K. Kurosaki, H. Muta, S. Yamanaka. Annealing efect on thermoelectric properties of TiCoSb half-Heusler compound. J. Alloy. Compd. 394, 122 (2005).
     CrossRef
  8. Y. Xia, V. Ponnambalam, S. Bhattacharya, A.L. Pope, S.J. Poon, T.M. Tritt. Electrical transport properties of TiCoSb half-Heusler phases that exhibit high resistivity. J. Phys.: Condens. Matter 13, 77 (2001).
     CrossRef
  9. I. Skovsen, L. Bjerg, M. Christensen, E. Nishibori, B. Balke, C. Felser, B.B. Iversen. Multi-temperature synchrotron PXRD and physical properties study of half-Heusler TiCoSb. Dalton Trans. 39, 10154 (2010).
     CrossRef
  10. D. Singh. Plane Waves, Psedopotentials and LAPW Method (Kluwer Academic, 1994).
     CrossRef
  11. J.P. Perdew, S. Burke, M. Ernzerhof. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865 (1996).
     CrossRef
  12. P. Blaha, K. Schwarz, G.K.Madsen, D. Kvasnicka, J. Luitz. WIEN2k, An Augmented Plane Wave + Local Orbitals Program for Calculating Crystal Properties (Vienna Univ. of Technology, 2001) [ISBN 3-9501031-1-2].
  13. http://www.wien2k.at/reg_user/faq/.
  14. B.R.K. Nanda, I. Dasgupta. Electronic structure and magnetism in half-Heusler compounds. J. Phys.: Condens. Matter 15, 7307 (2003).
     CrossRef
  15. S. Ouardi. Ph.D. thesis Electronic Structure and Physical Properties of Heusler Compounds for Thermoelectric and Spintronic Applications (J. Gutenberg-Universit¨at Mainz, 2012).
  16. V.N. Uvarov, I.V. Urubkov, E.V. Urubkova, V.V. Klimov, O.Yu. Khizhun, V.V. Trachevskii. Electron structure of NaVP2O7 and NaFeP2O7 pyrophosphates: X-ray, photo-electron, NMR spectra and band structure calculations. Metallofz. Noveish. Tekhnol. 33, 145 (2011) (in Russian).
  17. V.M. Uvarov, M.P. Melnyk, M.V. Uvarov, V.S. Mykhalenkov, T.L. Syzova. Electron structure of GdMeO3 (Me = V, Ni) oxides: X-ray electron, X-ray spectra and band structure calculations. Metallofz. Noveish. Tekhnol. 35, 279 (2013) (in Ukrainian).
  18. J. Tobola, J. Pierre, S. Kaprzyk, R.V. Skolozdra, M.A. Kouacou. Crossover from semiconductor to magnetic metal in semi-Heusler phases as a function of valence electron concentration. J. Phys.: Condens. Matter 10, 1013 (1998).
     CrossRef