Observation of the Quadrupole Interaction at Ta in Zr by Time - Differential Perturbed Angular Correlation Technique

Abstract

The 482 keV excited state of the nucleus 181Ta is a useful probe of internal hyperfine fields in solids. The level has large magnetic dipole and electric quadrupole moments1 ) (μ= 3.2 nm, Q = 2.5b) and there is a large angular correlation coefficient1 ) (A22 ≈ − 0.28) for the strongly fed gamma — gamma cascade, l/2+ (133 keV, E2) 5/2+ (482 keV, Ml + E2) 7/2+, through the level. Also the life — time of the intermediate state1 ) (τ = 1.06 × 10−8 s) is in the range where a time — differential method, which yields maximum information regarding the interaction, may be employed. Knowledge of the electric field gradient (EFG) at impurity sites in non — cubic metals and its dependence on temperature can contribute to understanding the role of the conduction band in shielding the crystal field. To this end, we are investigating the hyperfine interaction at Ta in hcp Zr using the time — differential perturbed angular correlation technique.