Giant Hall effect in Co-SiO₂nanocomposites

Abstract

Measurements of both the ordinary and extraordinary components of the Hall effect in co-sputtered granular magnetic Co-SiO₂ nanocomposites are presented. The experiments were done in the temperature range 5-300 K, and fields up to 7 T. Both components show a large enhancement when the metal volume fraction is reduced to the metal-insulator transition. However the enhancement of the ordinary Hall effect is much weaker than that of the extraordinary one. We discuss the implications of this observation for understanding of the giant Hall effect.