具垂直異向性之一維磁性多層奈米線與磁性穿隧接面奈米元件

Abstract

具垂直磁異向性之奈米材料於發展下一代磁紀錄媒體與磁電阻式隨機存取記憶體扮演極重要的腳色。結合電化學電沉積技術與具奈米孔洞之氧化鋁模板可達成大量製造、低成本與高密度之目標。本研究所製備之鈷與鎳鐵合金之奈米線被證實具備垂直磁異向性且可透過磁晶異向性與形狀異向性來調整。結合具垂直磁異向性之鎳鐵合金奈米線與鈷鐵硼薄膜之磁性穿隧接面元件已成功被製造與探討。於低溫10K的環境下，鈷鐵硼薄膜厚度為1.5奈米時，其磁阻為104%，而鈷鐵硼薄膜厚度為1.0奈米時，其磁阻為110%，且在鈷鐵硼薄膜厚度小於1.0奈米時，於無固定層的條件下元件呈現出自旋閥的特性。

The nanometer size magnetic materials with perpendicular anisotropy are more important to develop the next generation magnetic recording media or magnetoresistive random access memory. The magnetic nanowire via electrochemical deposition into the anodic alumina oxide template is one possible method to achieve the goal of massive fabrication, low cost and high density. The magnetic nanowires of cobalt and permalloy have demonstrated that the perpendicular anisotropy can be tunable by controlling the magnetocrystalline and shape anisotropy. The nanometer perpendicular magnetic tunnel junctions are prepared and the feasibility is also has been demonstrated. The TMR ratio o MTJs with 1.0 nm thick CoFeB layer are 110% at 10K and with 1.5 nm thick CoFeB layer are 104% at 10K. Below the 1.0 nm thick of CoFeB layer, the MTJs display the spin valve like properties without pinned layer and the spin quantum limitation was observed at 10K.