Broadband magnetic losses of nanocrystalline ribbons and powder cores

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:420

Article

Beatrice, Cinzia¹  Dobak, Samuel²  Ferrara, Enzo¹  Fiorillo, Fausto¹  Ragusa, Carlo³  Fuzer, Jan²  Kollar, Peter² 

[1] Ist Nazl Ric Metrol, Nanosci & Mat Div, Turin, Italy

[2] Safarik Univ, Fac Sci, Inst Phys, Kosice, Slovakia

[3] Politecn Torino, Dept Energy, Turin, Italy

关键词: Nanocrystalline alloys;    Magnetic losses;    High-frequency losses;    Landau Lifshitz equation;   

DOI  :  10.1016/j.jmmm.2016.07.045

来源: Elsevier

【 摘 要 】

Finemet type alloys have been investigated from DC to 1 GHz at different induction levels upon different treatments: as amorphous precursors, as ribbons nanocrystallized with and without an applied saturating field, as consolidated powders. The lowest energy losses at all frequencies and maximum Snoek's product are exhibited by the transversally field-annealed ribbons. This is understood in terms of rotation dominated magnetization process in the low-anisotropy material. Intergrain eddy currents are responsible for the fast increase of the losses with frequency and for early permeability relaxation of the powder cores. Evidence for resonant phenomena at high frequencies and for the ensuing inadequate role of the static magnetic constitutive equation of the material in solving the magnetization dynamics via the Maxwell's diffusion equation of the electromagnetic field is provided. It is demonstrated that, by taking the Landau Lifshitz Gilbert equation as a constitutive relation, the excellent frequency response of the transverse anisotropy ribbons can be described by analytical method. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free