Analysis of the magnetoresistance contributions in a nanocrystallized Cr-doped FINEMET alloy

• Published in: Journal of magnetism and magnetic materials Vol. 323; no. 6; pp. 699 - 707
• Main Authors: Kiss, L.F., Franco, V., Csontos, M., Péter, L., Conde, C.F., Conde, A., Kemény, T., Tóth, J., Varga, L.K., Bakonyi, I.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2011; Elsevier
• Subjects: Amorphous alloys; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Ferrous alloys; Fe–Si alloys; FINEMET alloys; Giant magnetoresistance; Iron; Joining; Magnetic properties and materials; Magnetoresistance; Magnetoresistivity; Magnetotransport phenomena, materials for magnetotransport; Nanocomposites; Nanocrystallization; Nanocrystals; Nanomaterials; Nanostructure; Physics; Scattering; Nanocrystallization; FINEMET alloys; Amorphous alloys; Magnetoresistance; Fe–Si alloys; Ordered alloy; Crystallization; Conduction electron; Magnetic field effects; Chromium additions; Giant magnetoresistance; Dipole interactions; Amorphous phase; Granular structure; Magnetic susceptibility; Fe-Si alloys; High field; Electron spin interaction; Microstructure; Exchange interactions; Nanocrystal; Iron base alloys
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2010.10.026

The magnetoresistance (MR) was measured at 200, 250 and 300K in magnetic fields up to B=12T for a nanocrystallized Fe63.5Cr10Nb3Cu1Si13.5B9 alloy. Both the longitudinal (LMR) and transverse (TMR) component of the magnetoresistance decreased from B=0 to about 0.1T. This could be ascribed to a giant MR (GMR) effect due to spin-dependent scattering of conduction electrons along their path between two Fe–Si nanograins via the non-magnetic matrix. Such a scattering may occur if the nanograin moments are not or only weakly coupled in the absence of a strong exchange coupling (due to the high Cr content in the matrix) and/or only weak dipole–dipole coupling is present (due to sufficiently large separations between the nanograins). For larger fields, the GMR saturated and a slightly nonlinear increase in MR with B was observed due to a contribution by the residual amorphous matrix. The anisotropic MR effect (AMR≡LMR−TMR) was negative for all fields and temperatures investigated. By measuring the MR of melt-quenched Fe100−xSix solid solutions with x=15, 18, 20, 25 and 28, the observed AMR could be identified as originating from the Fe–Si nanograins having a D03 structure. ► Magnetoresistance (MR) of nanocrystallized Fe63.5Cr10Nb3Cu1Si13.5B9 up to 12T. ► Small GMR effect due to non-aligned neighbouring Fe–Si nanograins. ► For large fields, slightly nonlinear MR due to the residual amorphous matrix. ► Negative AMR of the Fe–Si nanograins exhibiting the D03 structure. ► Negative AMR reported on melt-quenched Fe100−xSix solid solutions (15≤x≤28).