Development of half-metallic ultrathin Fe₃O₄ films for spin-transport devices

We attempted to fabricate a high-quality Fe₃O₄ film while satisfying both low-thermal preparation (≦573 K) and film thinness (≦500 Å). X-ray diffractometry showed that our prepared Fe ₃O₄ film was epitaxially grown onto a MgO (100) substrate. The saturation magnetization, resistivity, and Verwey point were, respectively, ∼438emu/cm³, ∼10000μcm, and ∼110K. These values were comparable to those of the Fe₃O₄ bulk. Our experimental results suggested that a high-quality Fe₃O₄ film could be obtained even under the crucial conditions of the deposition temperature being low (∼523 K) and the film being ultrathinned (∼100 Å).