Using in-situ X-ray diffraction and ab initio theoretical calculations
, we have identified a possible new phase of iron, epsilon'-Fe, in the
stability field of what was previously known for epsilon(hcp)- and ga
mma(fcc)-Fe, The crystal structure of epsilon'-Fe is indexed to a dhcp
structure with an ABAC stacking sequence. The epsilon'-phase exists a
t temperatures lower than the gamma-phase and at pressures between 15
and 40 GPa, which differs from the stability field previously suggeste
d for beta-Fe above 40 GPa.