Study of constitutional and thermally created lattice defects in the β′-PdIn phase

Abstract

The TDPAC method with ¹¹¹In atoms as atomic probes has been used to study constitutional and thermal lattice defects of the β′-PdIn phase in the range 49 to 53 at.% Pd. It was found that no constitutional defects are present in the stoichiometric composition. On the In-rich side, the constitutional defects are exclusively single vacancies, which are randomly distributed over the Pd sublattice. On the Pd-rich aide, the constitutional defects are randomly distributed Pd anti-structure atoms. For the 53 at.% Pd composition clustering of defects was observed. The formation of thermal defects was studied by quenching various PdIn compositions from temperatures between 1130 and 1320 K. On either side of stoichiometry, as well as for the stoichiometric compound, an increasing concentration of randomly distributed single vacancies was observed in the Pd sublattice with increasing temperature.

Vacancies in the In sublattice mm to be 'invisible' to the TDPAC method with ¹¹¹In probes. On the In-rich side the formation of thermal Pd-site vacancies decreases with increasing deviation from the stoichiometric composition. On the Pd-rich side the concentration of Pd antistructure atoms decreases with increasing temperature. It is concluded that constitutional Pd antistructure atoms recombine with thermally created Pd-site vacancies. The thermal formation of localized or dissociated triple defects is excluded.