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Experiments were carried out on highly ordered GdAl samples containing extremely dilute mole fractions ofIn/Cd probe-atom solutes (about 10), intrinsic antisite atoms Al having mole fractions of order 0-10, and doped with Ag solutes at mole fractions of order 10. Three types of defect interactions were investigated. (1) Quadrupole interactions caused by Ag-solute atoms neighboringIn/Cd solute probe atoms were detected using the method of perturbed angular correlation of gamma rays (PAC). Three complexes of pairs of In-probes and Ag-solutes occupying neighboring positions on Gd- and Al-sublattices were identified by comparing site fractions in Gd-poor and Gd-rich GdAl(Ag) samples and from the symmetry of the quadrupole interactions. Interaction enthalpies between solute-atom pairs were determined from temperature dependences of observed site fractions. Repulsive interactions were observed for close-neighbor complexes In+Ag and In+Ag pairs, whereas a slightly attractive interaction was observed for In+Ag. Interaction enthalpies were all small, in the range ±0.15 eV. (2) Quadrupole interactions caused by intrinsic antisite atoms Al neighboring In probes were also detected and site fractions measured as a function of temperature, as in previous work on samples not doped with Ag-solutes [Temperature- and composition-driven changes in site occupation of solutes in GdAl, Zacate and Collins (Phys. Rev. B69, 174202 (1))]. However, the effective binding enthalpy between In probe and Al antisite was found to change sign from -0.12 eV (attractive interaction) in undoped samples to + 0.24 eV (repulsive) in Ag-doped samples. This may be attributed to an attractive interaction between Al antisite atoms and Ag-dopants that competes with the attractive interaction between In and Al defects observed in undoped samples. Alternatively, it may be attributed to competing flows of Ag and Al atoms that, in effect, change the numbers of available sites on the two sublattices (termed degeneracies). (3) The site preference of In-probes to occupy Gd- and Al-sublattices, without nearby defects, in Ag-doped samples was measured. Effective transfer enthalpies between the two sublattices were found in doped samples that were much smaller than the value 0.343(3) eV found in the previous study in undoped GdAl. Two approaches to understanding why the measured enthalpies in doped and undoped samples differ are discussed. [ABSTRACT FROM AUTHOR]

Due to technical constraints this correction was published in volume 240:1 with erroneous article citation ID number 9 whereas this should have been 79 which is corrected as such. Springer Nature sincerely apologizes towards the author(s) for the inconvenience caused. [ABSTRACT FROM AUTHOR]

This article has been corrected because one of the authors given names was incorrect. [ABSTRACT FROM AUTHOR]

Intermetallic compound Zr7Ni10 has been studied by perturbed angular correlation (PAC) spectroscopy to determine the electric field gradient and site occupation of Hf dopant in the compound. A mixture of phase components were found in this sample. The component with Vzz = 6.6(1)× 1021 V/m2 and η = 0.71(1) at room temperature has been assigned to Zr7Ni10 phase. In this sample, Zr2Ni7 and Zr8Ni21 phases were also found to be present along with Zr7Ni10. No phase transition is observed in the temperature range 77-1073 K in this sample. The electric field gradient (Vzz) for Zr7Ni10 phase was found to decrease linearly with temperature. The phase components in Zr7Ni10 have been determined also from X-ray powder diffraction (XRD) measurement. Theoretical calculations of EFG have been performed in Ta-doped Zr7Ni10 using all electron full potential (linearized) augmented plane wave [FP-(L)APW] method, within the framework of the density functional theory (DFT) to compare the results with the values obtained from PAC measurements and to know the site preference of 181Ta probe in the host matrix. [ABSTRACT FROM AUTHOR]