High resolution Mössbauer spectroscopy with67Zn in metallic systems

The high energy resolution of the 93.3 keV Mssbauer transition in67Zn is used to investigate changes of s-electron density at the Zn nucleus in Cu-Zn alloys with special emphasis on the α-phase and on Zn-metal itself. We observe the presence of short-range order in α-brass with only four different Cu-Zn configurations, instead of the expected binomial distribution. In Zn metal, no change of center shift was observed when crossing the superconducting phase transition. The tremendous anisotropy of the Lamb-Mssbauer factor, as well as the temperature shift found for hexagonal Zn metal, demonstrate that the 93.3 keV resonance is also extremely sensitive to lattice dynamical effects. Our results, as well as specific heat data, are quantitatively described by an extended Debye model characterized by two Debye temperatures, θ⊥ and θ‖, which correspond to the lattice vibrations perpendicular and parallel to thec axis, respectively.