NMR study of the crystallization kinetics in FINEMET-type materials

• Published in: Journal of alloys and compounds 2004-04, Vol.369 (1), p.136-140
• Main Authors: Barbatti, C.F, Sinnecker, E.H.C.P, Sarthour, R.S, Guimarães, A.P
• Format: Article
• Language: English
• Subjects: 93Nb resonance; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Local magnetic anisotropy; Magnetic properties and materials; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Nanocrystalline amorphous materials; NMR spectra; Nuclear magnetic resonance and relaxation; Physics
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2003.09.073

We have investigated the evolution of the structural and magnetic properties of Fe(Si)-based (FINEMET-type) nanocrystalline alloys using the NMR technique at zero field. NMR is a technique which provides structural information on different local atomic environments, and also allows the evaluation of the local magnetic anisotropy. Melt-spun ribbons of Fe 73.5Cu 1Nb 3Si (22.5− x) B x ( x=4, 6, and 9), which contain both amorphous and crystalline phases were studied as a function of the annealing temperatures ( T A). The 93Nb and 11B resonances were observed, and the magnetic stiffness associated with different local environments of 93Nb nuclei were determined. We observed that the Nb frequencies decrease with increasing T A, which suggests that Nb atoms migrate from either Fe-rich regions to Fe-poorer regions or to the B-richer phases. The local measurement of the anisotropy as a function of T A shows an equivalence to the behavior of the bulk coercivity as a function of T A.