J. Phys. IV France 08 (1998) Pr2-107-Pr2-110
Structural configuration and magnetic effects in as-milled and annealed nanocrystalline ironL. Del Bianco1, 2, A. Hernado1, E. Navarro1, E. Bonetti3 and L. Pasquin3
1 Instituto de Magnetismo Aplicado, UCM-RENFE, P. O. Box 155, Las Rozas, 28230 Madrid, Spain
2 Dipartimento di Fisica, Università di Bologna and Istituto Nazionale per la Fisica della Materia, Viale Berti Pichat 6/2, 40126 Bologna, Italy
3 Dipartimento di Fisica, Universita di Bologna and Istituto Nazionale per la Fisica della Materia, Viale Berti Pichat 612, 40126 Bologna, Italy
Mechanical spectroscopy, room temperature Mössbauer spectroscopy and magnetisation measurements have been employed to get insight into the structural relaxation process of the grain boundaries in 10 nm-grain sized iron powders produced by ball milling. In particular, by performing the Mössbauer analysis on milled powders previously subjected to proper thermal treatments in the 570-670 K range, the structural evolution of the grain boundaries has been followed through the changes int the hyperfine magnetic field distribution associated to the interfacial region. The results are consistent with a decrease of the magnetic moment of the atoms at the interface, following the relaxation process.
© EDP Sciences 1998