Preparation of Half-metallic Fe_3O_4 Films

Half-metallic magnetic material Fe3O4 is a new kind of spintronics material, which can provide 100% spin polarization. The Fe element has many electronic valences, so the pure Fe3O4 is difficult to prepare. Therefore, in this paper we mainly focused on finding the optimal way to fabricate pure Fe3O4 film. Half-metallic Fe3O4 films grown on Si (100) substrates were prepared by DC magnetron reactive sputtering. The annealing temperatures were investigated carefully, and the polycrystalline Fe3O4 films fabricated on Ta buffer layer shown better properties than the film directly sputtering on Si substrate. The optimum condition for the formation of polycrystalline Fe3O4 under DC magnetron reactive sputtering was found. The negative magnetoresistance of polycrystalline Fe3O4 was also tested, and showed a very weak saturation trend as the single-crystalline Fe3O4 films.