SMALL-ANGLE NEUTRON-SCATTERING STUDY ON FE-CU-NB-SI-B NANOCRYSTALLINEALLOYS

Small-angle neutron scattering (SANS) from Fe-Cu-Nb-Si-B nanocrystalli ne alloys has been measured in a magnetic field. Significant differenc es between nuclear and magnetic scattering profiles have been observed . Most of the magnetic scattering profiles take an asymptotic form of I(q)similar to q(-3) in a high-q region, which indicates that the dist ribution of local magnetization is not uniform in a BCC-Fe grain. All the nuclear scattering profiles, on the other hand, take an asymptotic form of I(q)similar to q(-2), which implies that the concentration fl uctuation of the Ornstein-Zernike type exists in nanocrystalline alloy s. However, no such fluctuation is observed in Fe-Cu-Si-B and Fe-Nb-Si -B alloys which do not have any nanocrystalline structures. These resu lts suggest that the concentration fluctuation of the Ornstein-Zernike type seems to be closely related to the nanocrystalline microstructur es.