The layered intermetallic compound ZrBe2(H/D)x (x ≈ 1.5) was studied using D and Be nuclear magnetic resonance. A temperature-induced structural transition in the deuteride reported earlier was further investigated here using 9Be nuclear magnetic resonance, which revealed the transition in both the hydride and deuteride at 200 and 235K, respectively. Above the transition temperature a single pair of quadrupolar satellites was present. Each quadrupolar satellite splits into two resonances below the transition temperature, implying the existence of two different classes of Be sites. The temperature dependence of the satellite frequencies and the appearance of two-phase coexistence spectra showed the transition to be first order. Be-D spin-echo double resonance experiments were performed to identify the two sites; spin-echo double resonance demonstrated that the D environments of the two classes of Be sites were similar. Electronic structure calculations showed the binding energy of H decreased gradually for x greater than 1.38. The calculations allow a vacancy ordered structure to be proposed.

Vacancy Ordering Phase Transition in ZrBe2(H/D)x - NMR and Electronic Structure Study. V.D.Kodibagkar, P.A.Fedders, C.D.Browning, R.C.Bowman, N.L.Adolphi, M.S.Conradi: Physical Review B, 2003, 67[4], 045107 (7pp)