Cobalt--Ferrous ferrite with re-entrant hysteresis loop

Author

Edwards, G.W. ; Glaister, R.M.

Author_Institution

Standard Telecommunication Laboratories, Harlow-Essex, England

Volume

2

Issue

4

fYear

1966

fDate

12/1/1966 12:00:00 AM

Firstpage

696

Lastpage

702

Abstract

If the field Hrrequired to initiate flux reversal exceeds the Hwrequired to continue reversal, a re-entrant hysteresis loop results. This has been observed in magnetically annealed cobalt-ferrous ferrites in which Hrat 10 to 20 Oe may be as high as $1.5 \\times H_{w}$ at room temperature. Frequently, these ferrites are bistable and show no minor loops. Flux reversal appears to involve only one domain wall, giving rise to high squareness but slow switching ; typical values for a 12-mm toroid are $R_{s} = 0.99$ and $s = 540 \\mu$ s Oe. Intermediate stabilized magnetization states have been introduced into these materials by a simple annealing procedure. Switching now occurs between three or more magnetization states, providing the basis for a multistable device. Details of preparation and measurement are given and the results discussed in terms of various models.

Keywords

Cobalt ferrites; Hysteresis loops; Annealing; Ferrites; Magnetic domain walls; Magnetic domains; Magnetic flux; Magnetic hysteresis; Magnetic materials; Magnetic switching; Magnetization; Toroidal magnetic fields;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.1966.1065996

Filename

1065996