Effect of slowly relaxing impurities on ferrimagnetic resonance linewidths of single crystal nickel ferrites

Author

Torres, L. ; Zazo, M. ; Iniguez, J. ; de Francisco, C. ; Munoz, J.M.

Author_Institution

Dept. de Fisica Aplicada, Salamanca Univ., Spain

Volume

29

Issue

6

fYear

1993

fDate

11/1/1993 12:00:00 AM

Firstpage

3434

Lastpage

3436

Abstract

Ferrimagnetic resonance (FMR) linewidths have been measured at X-band frequencies (11 GHz) from 77 K to 400 K in single crystal nickel ferrites with composition Ni_xFe_3-xO ₄ with x=0.9, 1.0, 1.2. Measurements have been carried out by means of an automatic technique based on a modified short-circuit SMA transmission line. Linewidths ranged from 40 Oe to 80 Oe in all the temperature range. The dependence of the FMR linewidth with temperature leads to a contribution of the valence-exchange mechanism for x<1 and a contribution of the Ni²⁺ ion acting as a slowly relaxing impurity for x>1. The collection of data obtained by the automatic system allows the authors to achieve the values for the relaxation times and activation energies of these mechanisms

Keywords

exchange interactions (electron); ferrimagnetic properties of substances; ferrimagnetic resonance; ferrites; magnetic impurity interactions; nickel compounds; spectral line breadth; 11 GHz; 77 to 400 K; Ni_xFe_3-xO₄; X-band frequencies; activation energies; ferrimagnetic resonance linewidths; ferrites; ferromagnetic relaxation; relaxation times; single crystal; slowly relaxing impurities; temperature dependence; valence-exchange mechanism; Ferrimagnetic materials; Ferrites; Frequency measurement; Impurities; Iron; Magnetic resonance; Nickel; Temperature dependence; Temperature distribution; Transmission line measurements;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.281187

Filename

281187