Domain Structure of Titanomagnetites and Its Variation with Temperature

Abstract

In a Tertiary lava flow with optically apparently homogeneous titanomagnetites (Curie temperatures less than 100°C) a range of Curie temperatures from less than -40°C in the central to more than 70°C in the marginal zones of the crystals was found by observing the variation of the domain structure with temperature. The effect is explained by the different degree of maghemitization. TRM production in fields of 35 Oe revealed that the direction of the external field had little influence on the magnetic domain pattern.