Interdependence of thermal aftereffect and natural aging in permanent magnet materials

Author

Dietrich, Hermann E.

Author_Institution

Forschungsinstitut der Deutschen Edelstahlwerke AG, Krefeld, Germany

Volume

6

Issue

2

fYear

1970

fDate

6/1/1970 12:00:00 AM

Firstpage

272

Lastpage

275

Abstract

The thermal aftereffect is proportional to the irreversible susceptibility $\\chi irr$ and thus has a peak value in the zone of coercive force. It follows a logarithmic time law of the type $\\Delta I= S \\cdot \\log t + const$ whose constant $S$ shows a linear increase with the absolute temperature $T$ . The quotient $S/\\chi irr$ is a material constant and proportional to the coercive force. Natural aging also follows a law of the form $\\Delta B = S \\cdot \\log t + const$ , but is not proportional to $\\chi irr$ and therefore does not have a peak value in the zone of coercive force. Natural aging disappears at the remanence and at the coercive force. The constant $S$ of natural aging is proportional to the product $I \\cdot H \\cdot \\chi irr$ and inversely proportional to the coercive force. The quotient $S/\\chi irr$ is, in this case, not a material constant and not proportional to the coercive force.

Keywords

Permanent magnet materials; Aging; Barium; Coercive force; Ferrites; Magnetic materials; Magnetic susceptibility; Permanent magnets; Saturation magnetization; Temperature; Thermal force;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.1970.1066747

Filename

1066747