Browsing by Author "Rykavets, Zlata"

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    Experimental and First-principle study of TmNiSb half-Heusler Alloy
    (Видавництво Львівської політехніки, 2017-12-23) Rykavets, Zlata; Ryzhak, Diana; Romaka, Lyubov; Shvachko, Sergiy; Romaka, Vitaliy; Lviv Polytechnic National University; Ivan Franko National University of Lviv
    The studied TmNiSb alloy crystallizes in the MgAgAs structure type (half-Heusler phases) and according to the results of DFT+U calculations revealed the presence of bandgap (Eg = 359 meV). Spin magnetic moment of Tm atoms equals 2.16 μB confirming its Tm3+ state. Calculated elastic properties as well as Vickers hardness of TmNiSb alloy was defined semi-empirically and equals 15.98 GPa. Experimentally determined microhardness is within the range of 2.90 – 4.06 GPa with the exception of TmNiSb phase.
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    Structural disorder in TiFeSb half-Heusler antimonide
    (Lviv Polytechnic Publishing House, 2016) Romaka, Vitaliy; Rykavets, Zlata; Krayovskyy, Volodymyr; Romaka, Lyubov; Lviv Polytechnic National University; Ivan Franko National University of Lviv
    The DFT modeling of the TiF1+xSb solid solution revealed that composition TiFe1.375Sb with MnCu2Al structure type is more preferable than equiatomic TiFeSb which crystallizes in MgAgAs-type. At T > 873 K the formation of the two phase region containing both half-Heusler and full-Heusler phases is predicted. The composition dependence of the lattice parameter shows deviation from linearity. The calculations explain the difficulties in solid solutions formation based on TiFeSb intermetallic.