Temperature induced shift of the demagnetization curve of anisotropic ferrite magnets^*

¹ Philips Components, BU Magnetic Products, BE 2, P.O. Box 218, 5600 MD Eindhoven, The Netherlands
² Philips Composants Évreux, 41 rue Pierre Brossolette, BP 1642, 27016 Évreux, France

Corresponding author: eric.brando@eur.comp.philips.com

Received: 14 April 1998
Revised: 7 August 1998
Accepted: 28 August 1998
Published online: 15 December 1998

Abstract

Higher specifications and more narrow tolerances for electrical motor appliances give sense to a renewed interest in the temperature dependence of the demagnetization curve of anisotropic ferrite magnets. Based on physical backgrounds, a first approximation modelling is given for the temperature dependence of a working point, using the room temperature curve and some material and system characteristics. A procedure is derived to give the induced shift of the whole curve at any temperature (−100 to 300 °C). An important characteristic for the application is the field Hki, where irreversible flux losses start. Hence, the critical temperature decrease, at which Hki is reached in the system, is derived.