Manipulation of temperature dependence of coercivity in isotropic nanocrystalline permanent magnets

Author

Shigemoto, Y. ; Hirosawa, S.

Author_Institution

Res. & Dev. Div., NEOMAX Co. Ltd., Osaka, Japan

fYear

2005

fDate

4-8 April 2005

Firstpage

1651

Lastpage

1652

Abstract

The manipulation of the temperature dependence of coercivity, H_cJ(T), in Nd-Fe-B-Ti-C-M (M = Ca, Sr, Bi and Ga) nanocrystalline permanent magnets by modifying the intergranular exchange coupling coefficients, J_eff, is obtained. Such H_cJ manipulation is seen in a micromagnetic model describing the ratio of exchange energy and magnetocrystalline energy for a grain magnetically coupled to surrounding grains. The dependence of the absolute value of the temperature coefficient, alpha;(H_cJ), between 296 K and 373 K on cooling rate is observed in annealed ribbons.

Keywords

annealing; bismuth alloys; boron alloys; calcium alloys; coercive force; exchange interactions (electron); gallium alloys; grain boundaries; iron alloys; micromagnetics; nanostructured materials; neodymium alloys; permanent magnets; strontium alloys; titanium alloys; 296 to 373 K; NdFeBTiCBi; NdFeBTiCCa; NdFeBTiCGa; NdFeBTiCSr; annealing; coercivity; cooling rate; exchange energy; grains; intergranular exchange coupling coefficients; magnetocrystalline energy; micromagnetic model; nanocrystalline permanent magnets; temperature coefficient; Amorphous magnetic materials; Annealing; Bismuth; Coercive force; Magnetic anisotropy; Magnetic materials; Permanent magnets; Perpendicular magnetic anisotropy; Strontium; Temperature dependence;

fLanguage

English

Publisher

ieee

Conference_Titel

Magnetics Conference, 2005. INTERMAG Asia 2005. Digests of the IEEE International

Print_ISBN

0-7803-9009-1

Type

conf

DOI

10.1109/INTMAG.2005.1464259

Filename

1464259