Local structure study of 181Hf dopants in Zr7Ni10 by perturbed angular correlation spectroscopy and first principles calculations

Abstract

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.