Résumé
The effects of applied external pressure on the low temperature crystal and magnetic structures of LuFe2O4 have been investigated by means of synchrotron X-ray and neutron diffraction experiments in the range 0-3 GPa. Although the crystal structure is nearly rhombohedral at RT and ambient pressure, a marked monoclinic distortion is seen at low temperature, which increases with increasing pressure. In the magnetically ordered regime, the ordered magnetic moment value at 50K decreases by up to 30% at 3 GPa, although no evidence for magnetic diffuse scattering can be inferred from the data. A tentative explanation is proposed, based on the delocalization of the magnetic moment, and possibly related with a melting of the charge ordered state in this pressure range.