Pressure-induced change of the magnetic state in ordered Fe-Pt Invar alloy

The magnetic properties of an ordered Fe72.8Pt27.2 Invar alloy have been investigated under high pressures up to 7.5 GPa by AC susceptibility measurements in the temperature range from 4.2 to 430 K. The Curie temperature decreased with increasing pressure and then the ferromagnetic state vanished above 6.5 GPa. A new high-pressure magnetic phase appeared at 3.5 GPa in the low temperature range below 40 K, which is quiet different from the high-pressure phase observed in disordered Fe-Pt and Fe-Ni Invar alloys. The transition temperature to this new phase increased with pressure and the new phase became more stable. This tendency resembles to the feature expected by a recent theoretical calculation. (C) 2003 Elsevier B.V. All rights reserved.