Aerosol nanoparticles in the Fe1–xCrx system: Room-temperature stabilization of the phase and -phase transformation

8 pages, 12 figures, 1 table.-- PACS: 75.50.Tt; 75.30.Kz; 82.70.Rr; 75.30.Cr; 68.35.Dv; 81.40.Gh.-- et al.The production and structural characterization of gas-evaporated nanoparticles in the Fe1–xCrx system, with 0<x<0.83 are reported. The results show that for x~0.5 the metastable -FeCr can be stabilized and it constitutes up 60 wt % of the material. The sample with the highest -FeCr content is further analyzed to study the structural and the magnetic properties of this phase and its thermal stability. The -FeCr phase is weakly magnetic with an average magnetic moment of 0.1µB per Fe atom and a Curie temperature below ~60 K. It is stable up to 550 K where it starts to transform to bcc-FeCr. Annealing at 700 K yields Cr2O3 due to Cr surface segregation and affects the magnetic behavior of the system, which is dominated by interparticle interactions.This research has been supported by a NATO fellowship (OTSF03-074) and the CSIC-PAS exchange program (2004PL0009). C. Rovira (ICMAB-CSIC), for facilitating DSC measurements and E. Snoeck (CEMES-CNRS), for performing the HRTEM measurements, are acknowledged.Peer reviewe