Tunnel-type magneto-dielectric (TMD) effect arising from the spin-dependent quantum tunneling between nano-sized granular pairs, has opened up new route for room temperature magnetoelectric fields. We first investigated the TMD properties in metal-oxide (CoSiO2) granular films and their annealing effect in this work. Results show that the films exhibit a TMD ratio (¾0=¾00) of 1% with high electrical resistivity of >108 µ3·m and intermediate optical transmittance in Co0.24(SiO2)0.76 films. Annealing investigations suggest that the samples remain TMD response up to 573 K, and further increment in annealing temperature leads to the inter-diffusion between Co and SiO2 interfaces, thus producing the increasing oxidation of metallic Co. This study demonstrates the possibility of TMD effect in metal-oxide composite materials, and may be desirable for a variety of other wide oxide-based candidates for magnetoelectric device applications.
- Annealing effect
- Granular nano-composites
- Magneto-dielectric properties