Giant tunneling magnetoresistance in nanostructured ZnxFe3-xO4-alpha-Fe2O3polycrystalline material

Giant tunneling magnetoresistance effect (TMR) as large as 1280% at 4.2K an d 158% at 300K was observed in Zn-0.41 Fe2.59O4-alpha -Fe2O3 polycrystallin e sample. The Zn0.41Fe2.59O4 grains are separated by insulating alpha -Fe2O 3 thin layer boundaries. The pattern of nanostructure has been verified by TEM and HREM and the thickness of alpha -Fe2O3 boundary is about 6-7mn. The huge TMR is attributed to the high spin-polarization of Zn0.41Fe2.59O4 gra ins and insulating antiferromagnetic alpha -Fe2O3 thin layer. The ZnxFe3O4 ferrite is a new type half-metallic material with a huge TMR at room temper ature is interesting to further study in future.