¹⁸¹Ta perturbed-angular-correlation study of electric quadrupole interactions in yttrium metal and yttrium-hydrogen solid solutions

Abstract

The perturbed-angular-correlation (PAC) technique has been used to study the electric quadrupole interaction (QI) of the nuclear probe 181Ta in yttrium metal and yttrium-hydrogen solid solutions α-YHx with 0⩽x⩽0.2. The temperature dependence of the quadrupole frequency νq of 181Ta in yttrium metal, measured in the range 290 K⩽T⩽1700 K, follows the linear relation νq(T) = νq(0)(1-AT) with νq(0) = 423(3) MHz and A = 4.74(4)×10-4 K-1. The absorption of hydrogen enhances the temperature dependence of the QI: the parameters νq(0) and A of the linear temperature variation of the 181Ta QI in α-YHx measured between 25 K and 1000 K for 0⩽x⩽0.2 both increase with increasing concentration x. These trends are consistent with the anionic model of the electronic state of hydrogen in rare earth metals. At T⩾500 K a dynamic QI caused by diffusing hydrogen has been observed. The activation energy for hydrogen jumps in α-YH0.10 deduced from the temperature dependence of the quadrupole relaxation rate is Ea = 0.49(15) eV.

Perturbed Angular Correlation Spectroscopy – A Tool for the Study of Defects and Diffusion at the Atomic Scale

“…These are summarized in Table 2, arranged by the type of material and the general physical phenomenon considered. [60] • In in Zr 2 Rh [61] • In in HfAl 2 & ZrAl 2 [62] • In in Pd 3 Ga 7 [65] • In in Ni 2 Al 3 & related [66] • In in (Hf/Zr) 3 Al 2 & (Hf/Zr) 4 Al 3 [68] • In & Hf in bixbyites [63,64,67] • Hf in LiNbO 3 & LiTaO 3 [72] Probe:defect complex configurations [26] • Cd:acceptor and Cd:V Te charge states in CdTe [71] • Cd:vacancy in II-VI compounds [13] • Cd:acceptor in III-Vs, Si, and Ge [11,85,86] • In:V O in CeO 2 [69] • In:V O in CoO [70] • In:V O in CeO 2 [87] Probe:defect interactions • In:V Ni in NiAl [73] • In:V Fe in FeAl [26] • In:V Sm in SmNi 2 [75] • Probe:solute pairs in metals [4] • In:vacancy pairs in metals [9,[78][79][80][81] • In:V Cd in CdTe [74] • In:V Cd in CdS [76] • Pd:V Si in Si [77] • Cd:H in III-V compounds [11] • Cd:acceptors in Si & Ge [11] • Cd:V O in ZrO 2 [112] Atomic jumps • H near Hf in Y [94], Hf [95], & DyH 2±δ [96] • H near Cd in HfV 2 H x [98] • V R near Cd in R 1-x Ni 2 [75] • Cd in β-Mn ...…”

“…24b, the damping factor λ is proportional to the HFI A number of studies have utilized an empirical analysis to study defect jump rates near probes. These include the observation of H jumps near Hf in yttrium, hafnium, and dysprosium hydrides [94,95,96], of H jumps near Cd in Si [97] and HfV 2 H x [98], of Cu jumps near Cd in Si [99], of rare-earth (R) vacancy jumps near Cd in R 1-x Ni 2 [75], and of oxygen vacancies in R 2 M 2 O 7 (R = Nd, Sm, Eu, and Gd; M = Zr and Hf) pyrochlores [100] and in CeO 2 [69]. Examples of how such an empirical analysis has been used to study the motion of the PAC probe itself include studies of Cd jump rates in -Mn [101], Pd 3 Ga 7 [102], Pt 3 Ga 7 [103], Al 11 R 3 (R = La, Ce, Pr) [104], and LaSn 3 [105].…”