THERMALLY ACTIVATED DEMAGNETIZATION IN FE-SIO2 GRANULAR SOLIDS

(SiO2)(1-x)Fe-x samples, with 0.2 less than or equal to x less than or equal to 0.4, were prepared by high energy ball milling. We studied in these samples the temperature dependence of the magnetization, coercive force and thermally activated demagnetization parameters. From all these results it was concluded the occurrence, in all the examined samples, of two different maxima in the blocking temperature distributions, identified as corresponding to the extremes of the particle size distribution.