Pressure effect on the magnetic order of LuFe2O4
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.