Origin of coercivity of Ca - Ge substituted epitaxial YIG crystals

Author

Pardavi-Horváth, M. ; Cziraki, A. ; Fellegvari, I. ; Vertesy, G. ; Vandlik, J. ; Keszei, B.

Author_Institution

Central Research Institute of Physics, Budapest, Hungary.

Volume

20

Issue

5

fYear

1984

fDate

9/1/1984 12:00:00 AM

Firstpage

1123

Lastpage

1125

Abstract

LPE grown, substituted YIG crystals have coercivities (Hc) in the 10^-1Oe range, depending on compositions and growth conditions. Dislocations, inclusions and surfaces cannot be fully responsible for the observed Hc. TEM investigations of CaGeSmYIG films have revealed a periodically modulated stress field that - via magnetostrictive stresses - may explain the FMR line broadening and the measured Hc. Stresses of 10⁷dyne cm^-2and $\\Delta a/a \\simeq 10^{-5}$ with a periodicity of 500 Å produce $H_{c} \\simeq 1$ Oe corresponding to a periodic fluctuation of Sm or Ca-Ge content by 1-3%. The mechanism, thought to be the spinodal decomposition of the garnet, causes FMR line broadening up to 200-300 Oe, i.e. more than the relaxation of Sm³⁺ions.

Keywords

Coercive forces; Magnetic bubble films; YIG films/devices; Coercive force; Crystals; Garnet films; Helium; Internal stresses; Magnetic field measurement; Magnetic films; Magnetic modulators; Magnetostriction; Microstructure;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.1984.1063147

Filename

1063147