Behavior of Positrons in the HfNbTaTiZr Complex Concentrated Alloy

J. Kuriplacha, J. Čížeka, T. Vlasáka, O. Melikhovaa, F. Lukáča, b, J. Zýkac, J. Málekc aDepartment of Low Temperature Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, CZ-18000 Prague 8, Czech Republic bDepartment of Materials Engineering, Institute of Plasma Physics of CAS, Za Slovankou 1782, CZ-18200 Prague 8, Czech Republic cUJP PRAHA a.s., Nad Kamínkou 1345, CZ-15610 Prague 5 - Zbraslav, Czech Republic

Full Text PDF

The properties of positrons delocalized in the HfNbTaTiZr complex concentrated alloy are investigated theoretically and related to available experimental data. Positron lifetimes calculated for random atomic arrangements appear to be short compared to the experiment carried out on a vacancy-free sample. Contrarily, a configuration exhibiting a local atomic order provides a lifetime that is very close to the experimental value. These observations indicate that the local atomic order is occurring in the studied alloy, in agreement with other measurements. The analysis of calculated results shows that the positron lifetime and affinity are affected to some extent by the alloy substitutional disorder, lattice relaxations, and charge transfer among atomic species, which should be taken into account in precise calculations.

DOI:10.12693/APhysPolA.137.260 PACS numbers: 61.66.Dk, 78.70.Bj, 65.40.gd, 71.60.+z