Giant Hall effect in two-dimensional CoSi_2 granular arrays

Granular metals offer tailorable electronic properties and play crucial roles in device and sensor applications. We have fabricated a series of nonmagnetic granular CoSi2 thin films and studied the Hall effect and transport properties. We observed a two orders of magnitude enhancement in the Hall coefficient in films fall slightly above the metal-insulator transition. This giant Hall effect (GHE) is ascribed to the local quantum-interference effect induced reduction of the charge carriers. Transmission electron microscopy images and transport properties indicate that our films form two dimensional granular arrays. The GHE may provide useful and sensitive applications.