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

Abstract

a b s t r a c tThe magnetoresistance (MR) was measured at 200, 250 and 300 K in magnetic fields up to B ¼ 12 T for a nanocrystallized Fe 63.5 Cr 10 Nb 3 Cu 1 Si 13.5 B 9 alloy. Both the longitudinal (LMR) and transverse (TMR) component of the magnetoresistance decreased from B ¼ 0 to about 0.1 T. 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 À TMR) was negative for all fields and temperatures investigated. By measuring the MR of melt-quenched Fe 100 À x Si x solid solutions with x ¼15, 18, 20, 25 and 28, the observed AMR could be identified as originating from the Fe-Si nanograins having a D0 3 structure.

Magnetic and magnetoresistance studies of the evolution of the magnetic layer structure with Co layer thickness in electrodeposited Co–Cu/Cu multilayers

“…It is known that magnetoresistance is the result of spindependent scattering of conduction electrons in magnetic material and AMR arises if two successive electron scattering events occur within the same FM region, i.e., within the same Co-grain [27]. Therefore, if the conduction electron mean free path is higher than the size of Co nanograins, in this study, no AMR effect will arise.…”