Defect structures and nuclear electric hyperfine interactions were investigated in binary intermetallic compounds, and in NiTi, by using 27Al, 47,49Ti, 61Ni, 71Ga and 115In nuclear resonance. Components of the 61Ni nuclear magnetic resonance spectrum for a series of cubic Ni1-xAlx and Ni1-xGax specimens, on each side of x = 0.5, were identified as being due to Ni substitutions and Al or Ga vacancies. In stoichiometric NiAl, Ni2Al3 and NiAl3, the 61Ni lines were narrow and were distinguished by well-separated Knight shifts. However, the 61Ni lineshape for the ordered vacancy compound, Ni3Al4, indicated a substantial nuclear quadrupole interaction at the Ni site. The replacement of Al by group-III elements (Ga, In), which had iso-electronic outer shells, increased the 61Ni Knight shift; such that 61K(Al) < 61K(Ga) < 61K(In). This trend was observed for cubic NiAl and NiGa, and also for trigonal Ni2Al3, Ni2Ga3 and Ni2In3. In NiTi, the sharp first-order transition between the (high-temperature) cubic phase and the (low-temperature) monoclinic phase was observed when monitoring the 61Ni and 49,47Ti nuclear magnetic resonance lineshapes as a function of temperature. In the non-cubic phases (including hexagonal ε-NiIn), the electric field gradient tensor components (Vzz, η) at the atomic sites were deduced from nuclear quadrupole perturbed 27Al, 47Ti, 61Ni, and 71Ga nuclear magnetic resonance lineshapes; together with 69Ga and 115In NQR transition frequencies.

Defects and Hyperfine Interactions in Ni–Y intermetallics (Y = Al, Ga, In, Ti) via 27Al, 47Ti, 61Ni, 69,71Ga and 115In Nuclear Resonance. T.J.Bastow, G.W.West: Journal of Physics - Condensed Matter, 2003, 15[49], 8389-406