67Zn Mössbauer study of Cu−Zn alloys at high pressure

The high-resolution 93.3-keV Mossbauer resonance in67Zn was used to investigate Cu−Zn alloys (brass) containing 16.6 wt.% Zn (α-phase) and 50.5 wt.% Zn (β'-phase) at pressures up to 6.2 GPa and at 4.2 K. The recoil-free fraction and the center shift change linearly with reduced volume. The decrease of the center shift is due to the second-order Doppler effect which is partially compensated by the increase of the s-electron density at the67Zn nucleus when the conduction electrons are compressed. In α-brass short-range order leads to four different Cu−Zn configurations. One of them exhibits a center shift which nearly coincides with that of the β'-phase.