  The present paper demonstrates the feasibility of X-ray Absorption
Spectroscopy (XAS) and X-ray Magnetic Circular Dichroism (XMCD) at high
pressure at the Fe-K edge on the ID24 energy dispersive beamline of the ESRF.
In 3d transition metals, performing experiments at the hard X-ray K-edge rather
than at the magnetically interesting soft X-ray L-edges represents, the only
way to access the high pressure regime obtainable with Diamond Anvil Cells. The
simultaneous availability of a local structure (XAS) and of a magnetic (XMCD)
probe on the sample in identical thermodynamical conditions is essential to
study correlations between local structural and magnetic properties. We briefly
summarize the state of the art theoretical understanding of K-edge XMCD data,
then illustrate the setup of beamline ID24 for high pressure XMCD experiments
and underline the conditions required to perform measurements at the K-edges of
3d transition metals. Finally, we present two examples of recent high pressure
results at the Fe-K edge in pure Fe and Fe3O4 powder.
