The effect of texture on Curie-Weiss behaviour in a frozen ferrofluid

The initial susceptibility chi of a textured frozen dilute magnetite (Fe/sub 3/O/sub 4/) ferrofluid has been measured in the temperature range 80-180 K for different freezing magnetic fields H/sub f/. The texture is induced by cooling the ferrofluid to the solid state in the presence of an H/sub f/ of less than 220 Oe. The frozen ferrofluid exhibits Curie-Weiss behaviour. Using these results it is found that chi varies linearly with the square of H/sub f/, which agrees with a theoretical model for a noninteracting textured fine particle system in a solid matrix. It is suggested that the presence of particle aggregates in the ferrofluid can be detected through the study of the ordering temperature.< >