Study of the electric quadrupole interaction at Ta impurities in rare earth metal hosts

Temperature and Pressure Dependence of the Impurity Electric Quadrupole Interaction: Cadmium and Tantalum in Terbium

“…ing. This agrees with the results of Forker et al [7,22] and suggests, that the preparation of dilute Hf-rare earth alloys suffers from fundamental problems. Only a fraction of about 40% of the Hf atoms are substitutional with an unperturbed environment.…”

“…The quadrupole frequencies at room temperature, the relative changes with tkmperature, (d In q/dT),, K , and with pressure, (d In q/dP)300K, for '"Ta and "'Cd in Tb are compiled in Table I. The agreement in vQ with the result of Forker et al [7] at 3 0 0 K is excellent. However, we did not find any need t o allow for a sizeable frequency distribution nor for a violation of axial symmetry.…”

“…It is worth mentioning, however. that the quadrupole frequency at 300K, vQ = e2qQ/h = 286(23) MHz, is considerably lower than Forker's result [7]. This discrepancy is not understood at present and cannot be attributed t o the rather poor quality of the spectra alone.…”

“…The electric quadrupole interaction at "'Cd and ls'Ta impurities in different rare earth metals has been studied previously by Forker et al [7,22], Rasera et al [21] and by Lis et al [23]. The angular correlation spectra for Ta in all the rare earths studied showed a too small anisotropy andin earlier workalso a broad frequency distribution, indicating that imperfect samples have been used.…”