Measurements were made of the temperature-dependence of electric and magnetic hyperfine interactions at 181Ta nuclei which were substituted at Zr sites in this Laves-phase compound. The measurements were performed by using the perturbed angular correlation of γ-rays which were emitted after the ß- decay of 181Hf probe nuclei. Although the overall crystal structure was cubic, a weak and strongly-damped electric quadrupole interaction was observed. This exhibited no significant temperature dependence at temperatures ranging from 290 to 1300K. Combined magnetic-dipole and electric-quadrupole hyperfine interactions were observed below the magnetic ordering temperature of 631K. Two separate magnetic components characterized the magnetic-dipole interactions. For interactions at the primary site, which was occupied by 70 to 80% of the probes, the Larmor frequency was 407Mrad/s. The secondary site was populated by the remaining 20 to 30% of the probes, for which the corresponding Larmor frequency at room temperature was 579Mrad/s. The primary interaction was attributed to the so-called perfect-crystal probe environment at the Zr site. The secondary interaction was attributed to an enhancement, of the transferred hyperfine field, due to the presence of Fe antisite defects near to the Zr site.

Defects and Magnetic Hyperfine Fields in ZrFe2 Investigated using Perturbed Angular Correlation Spectroscopy. A.T.Motta, G.L.Catchen, S.E.Cumblidge, R.L.Rasera, A.Paesano, L.Amaral: Physical Review B, 1999, 60[2], 1188-96