Free Volume Diffusion and Optimisation of Soft Magnetic Properties in Amorphous Alloys Based on Iron

Influence of rare earth elements on crystallization of Fe82Nb2B14RE2 (RE=Y, Gd, Tb, and Dy) amorphous alloys

“…Such alloys are of great importance for the reason that in these types of materials the enhancement of soft magnetic properties (ESMP) effect can be observed [1][2][3][4][5]. This effect is connected with particular structural changes taking place during thermal annealing in temperatures close to the crystallization and is usually explained by magnetic interactions between iron nanograins.…”

“…It is also known that in the case of Fe-Nb-B (NANOPERM type) amorphous alloys the ESMP effect occurs just in the relaxed amorphous phase without formation of a nanostructure [2][3][4][5]. Our recent investigations concerning this behavior have led to a hypothesis of formation of small iron cluster acting as a special kind of sub-nanograins which according to the random anisotropy model cause the increase of magnetic permeability, decrease of coercive field as well as magnetic losses [1,2]. Taking into account what was mentioned earlier, Fe-Nb-B type of amorphous and nanocrystalline materials can be applied in electronics as magnetic cores of discrete elements, sensors or actuators.…”

Studies of the relaxed amorphous phase in the Fe80Nb6B14 alloy

“…for the Fe 80 Nb 6 B 14 alloy about 14 times). In a series of papers [6][7][8], the ESMP effect is usually explained by a decrease of free-volume content and magnetostriction coefficient, which is connected with annealing out of internal stresses.…”

Optimization of Soft Magnetic Properties in Fe82Nb2B14RE2 (RE = Y, Gd, Tb and Dy) Group of Amorphous Alloys

“…After such annealing a low field magnetic permeability can increase even 20 times and a coercive field can go down below 1 A/m [1][2][3][4][5][6][7][8]. The observed effects are explained by formation of an optimized microstructure which in general can be of two types: (i) iron nanograins embedded into a residual amorphous phase [1][2][3][4][5] or (ii) the so-called relaxed amorphous phase free of iron nanograins for which free volume and internal stresses are significantly reduced [2,[6][7][8]. The type of the optimized microstructure strongly depends on alloying additions and parameters of the applied annealing.…”