Abstract We successfully fabricated perpendicularly magnetized cobalt-ferrite Co x Fe 3 - x O 4 + δ (0 0 1) films on nonmagnetic metal TiN (0 0 1) films. We found that the in-plane lattice constant of the Co x Fe 3 - x O 4 + δ (0 0 1) films was larger than the out-of-plane lattice constant. This lattice strain induced perpendicular magnetic anisotropy, and square hysteresis curves were observed in out-of-plane magnetic fields for the Co x Fe 3 - x O 4 + δ (x = 0.4 ∼ 0.6) films. With the decrease of the Co composition from x = 1 to x = 0, the Co x Fe 3 - x O 4 + δ films approached not to conductive Fe 3 O 4 but to insulating γ - Fe 2 O 3 accompanying cation vacancies in the cubic spinel structure. The good tunneling conductivity character was observed for the Co x Fe 3 - x O 4 + δ tunnel junctions. The results open up a possibility that insulating Co x Fe 3 - x O 4 + δ films can be applied to elements of perpendicularly magnetized spintronics devices.

中文翻译：

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在非磁性金属薄膜上生长的外延钴铁氧体 (001) 薄膜的垂直磁各向异性和隧穿电导率

摘要 我们成功地在非磁性金属TiN (0 0 1) 薄膜上制备了垂直磁化的钴铁氧体Co x Fe 3 - x O 4 + δ (0 0 1) 薄膜。我们发现 Co x Fe 3 - x O 4 + δ (0 0 1) 薄膜的面内晶格常数大于面外晶格常数。这种晶格应变引起垂直磁各向异性，在 Co x Fe 3 - x O 4 + δ (x = 0.4 ∼ 0.6) 膜的面外磁场中观察到方形磁滞曲线。随着 Co 组成从 x = 1 减少到 x = 0，Co x Fe 3 - x O 4 + δ 薄膜接近于绝缘的 γ - Fe 2 O 3 伴随的阳离子空位而不是导电的 Fe 3 O 4立方尖晶石结构。对于 Co x Fe 3 - x O 4 + δ 隧道结，观察到良好的隧道传导特性。