Nanocrystalline M-type hexaferrite powders: preparation, geometric and magnetic properties

Author

Gornert, P. ; Pfeiffer, Helge ; Sinn, E. ; Muller, R. ; Schüppel, W. ; Rösler, M. ; Batlle, X. Garcia ; Garcia del Mure, M. ; Tejada, J. ; Gali, S.

Author_Institution

Inst. fur Phys. Hochtechnol., Jena, Germany

Volume

30

Issue

2

fYear

1994

fDate

3/1/1994 12:00:00 AM

Firstpage

714

Lastpage

716

Abstract

Co-Ti-Sn-Ge substituted M-type bariumhexaferrite powders with mean grain sizes between about 10 nm and about 1 μm and a narrow size distribution were prepared reproducibly by means of a modified glass crystallization method. At annealing temperatures between 560 and 580°C of the amorphous flakes nanocrystalline particles grow. They behave superparamagnetically at room temperature and change into stable magnetic single domains at lower temperatures. The magnetic volume of the powders is considerably less than the geometric one. However, the effective anisotropy fields are larger by a Factor of two to three

Keywords

annealing; barium compounds; ferrites; magnetic anisotropy; magnetic properties of amorphous substances; magnetic properties of fine particles; nanostructured materials; powders; superparamagnetism; 560 to 580 C; BaFe_12-2xCo_xTi_x-y-zSn_yGe_zO₁₉; BaFe₁₂CoTiSnGeO₁₉; amorphous flakes; anisotropy fields; annealing temperatures; glass crystallization method; magnetic domains; magnetic volume; mean grain size; nanocrystalline hexaferrite powders; superparamagnetic; Amorphous magnetic materials; Annealing; Crystallization; Glass; Grain size; Magnetic anisotropy; Magnetic domains; Perpendicular magnetic anisotropy; Powders; Temperature;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.312385

Filename

312385