Electric-field gradients at the Zr sites in (formula presented)Measured using perturbed-angular-correlation spectroscopy and calculated using band theory

We have measured the electric-field-gradient (EFG) parameters (formula presented) and η and their temperature dependences at the two Zr sites in the intermetallic compound (formula presented) using perturbed-angular-correlation spectroscopy and the probe (formula presented) At temperatures below the peritectic transformation at ≈1158 K, at each Zr site, we observed well-defined EFG’s, characterized by sharp spectral lines. A high-frequency, very asymmetric nuclear electric-quadrupole interaction characterizes the first Zr site, which represents approximately one-third of the probes. A low-frequency, nearly axially symmetric nuclear electric-quadrupole interaction characterizes the second Zr site, which represents approximately two-thirds of the probes. Near and above the peritectic transformation, the results show the effects of the decomposition of (formula presented) into Zr and (formula presented) and subsequent melting. We have compared the values of (formula presented) and η measured at laboratory temperature to those calculated using the first-principles, self-consistent real-space linear muffin-tin atomic sphere approximation (RS-LMTO-ASA) band-theory method. Overall the magnitudes of (formula presented) and η calculated using the RS-LMTO-ASA method agree reasonably well with the experimental values.