Title :
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
fDate :
11/1/1993 12:00:00 AM
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 NixFe3-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; NixFe3-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;
Journal_Title :
Magnetics, IEEE Transactions on
