Abstract: 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.

Key words: half-metallic material, spintronic material, Fe3O4 thin film