Observation of the Nuclear Resonance in Ferromagnetic Iron to 65 000 Atmospheres

Measurements have been made of the pressure dependence of the Fe57 nuclear resonance frequency (v) in ferromagnetic iron to 65 kbars using AgCl as a solid pressure transmitting medium in a belt-type press. v varies linearly with pressure with (∂v/∂P)T=25.5°C= −7.67±0.22 (kc/kbar). Absence of substantial line broadening above 15 kbars indicates that the pressure in our sample was essentially hydrostatic.