Effect of Temperature of Long Annealing on the Structure and Magnetic Properties of Nanocrystalline FeSiNbCuB Alloy

Abstract

The dependence of soft magnetic properties of the Fe 73.5 Si 13.5 Nb 3 Cu 1 B 9 alloy on the 2-hour air annealing temperature T an at temperatures from 520 to 620°C is studied. It is shown that the magnetic hysteresis loop is significantly broadens and becomes more inclined, and the Curie temperature of the amorphous matrix surrounding α-FeSi nanocrystals decreases with increasing T an . The atomic structure and phase composition of alloy samples are studied by transmission X-ray diffraction. After annealing at temperatures to 580°C, nanocrystals contain mostly D0 3 phase (Fe 3 Si stoichiometry) and are ~7 nm in average size. Their relative fraction in the alloy increases with temperature due to additional iron diffusion from the matrix to nanocrystals. After annealings at T an > 600°C, the average nanocrystal size increases, and iron boride crystal reflections appear in X-ray diffraction patterns. Degradation of soft magnetic properties of nanocrystalline Fe 73.5 Si 13.5 Nb 3 Cu 1 B 9 alloy with annealing temperature from 520 to 580°C is explained by a decrease in the silicon concentration in FeSi nanocrystals, which results in an increase in the magnetocrystalline anisotropy.

Anomalous Nernst Effect in Flexible Co-Based Amorphous Ribbons

“…Specifically, Figure 3 c discloses tilted domains, primarily orientated along the main axis of the ribbon. Figure 3 d shows typical zig-zag surface domains, a result of the stress annealing of Co-based ribbons, leading to a transverse magnetic anisotropy, which can be connected to the Fe–Fe or Cr–Cr pair ordering [ 51 , 52 , 53 ] as well as the non-uniform distribution of the internal stress. As a result, the induced anisotropy axis is oriented along the width of the ribbon [ 47 , 54 ].…”

Surface crystallization of amorphous Fe-=SUB=-73.8-=/SUB=-Si-=SUB=-13-=/SUB=-B-=SUB=-9.1-=/SUB=-Cu-=SUB=-1-=/SUB=-Nb-=SUB=-3.1-=/SUB=- and Fe-=SUB=-77.5-=/SUB=-Si-=SUB=-13.5-=/SUB=-B-=SUB=-9-=/SUB=- microwires

“…Amorphous-nanocrystalline materials obtained by heat treatment of amorphous iron-based alloys are well known for their magnetic properties, combining high values of magnetic permeability and saturation magnetization with low magnetostriction and low losses on remagnetization [1][2][3][4]. The Ternary alloys of the Fe-Si-B system, as well as Fe-Si-B alloys with the addition of other elements, in particular, Cu and Nb, are quite indicative here.…”