12:00 PM - 12:15 PM
[SMP42-12] Magnetic and Structural transition of Fe-Si alloy under high pressure
Keywords:Fe-Si alloy, Mossbauer spectroscopy, Magnetic transition, Structral stransition
The starting materials of Fe-Si alloys used for the measurements had compositions of Fe0.95Si0.05 or Fe0.88Si0.12 enriched with 57Fe. The mixture powder were heated in the Ar-H2 atmosphere by a double sided laser heating system and the molten samples were quenched to room temperature by shutting the laser. Mössbauer spectra and XRD patterns were obtained at the beamlines, BL10XU and BL11XU of SPring-8 up to 40 GPa at room and high temperature. Our Mössbauer data together with X-ray diffraction data revealed that the magnetic transition started to transform from magnetic to non-magnetic phase at around 15 GPa for Fe0.95Si0.05 and 14 GPa for Fe0.88Si0.12. This transition was likely simultaneous transition with the bcc to hcp transition. The magnetic and structural transition pressures increased as increasing Si amounts in the Fe-Si alloys. In addition, Mössbauer spectra and XRD patterns were obtained from room temperature to 700 K at about 7 GPa. As the temperature raised, the internal magnetic fields became small and bcc structure started to transform to fcc structure at 870 K and 8.0 GPa and only fcc structure was observed at 920 K and 8.0 GPa.