Pressure variation of the magnetic state in Co-Fe-Cr stainless Invar alloy

Magnetic properties of a Co52.5Fe38Cr9.5 Invar alloy have been investigated under high-pressure by ac susceptibility measurements. With increasing pressure, ferromagnetic ground state disappeared and new high-pressure magnetic states came to appear. Further increasing pressure up to 4.6 GPa, the high-pressure magnetic states vanished and no magnetic signal observed in the investigation range 5-300 K. These pressure variations of magnetic phases are similar to Fe based Invar alloy. So far considering from the series of our experimental results, it is concluded that the moment-volume instability in Invar alloys are associated with a several magnetically ordered phases that exist in low volume side of ground state. These facts support some theoretical model for the origin of Invar effect.