L10-FePt奈米線陣列之垂直磁性自旋閥
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2011
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本研究利用孔洞為50 nm之陽極氧化鋁(AAO)作為模板，再以電化學沉積之方式合成出FePt奈米線陣列。藉由X光繞射儀(XRD)觀察FePt奈米線陣列於700oC與5% H2/N2之環境下進行熱退火時FePt奈米線陣列將從無序相之面心立方晶格fcc轉換為有序L10相，FePt奈米線陣列於有序相L10相其矯頑磁場約為7.5 kOe，利用熱退火之方式，使L10相FePt奈米線陣列至（001）方向之磁化易軸。而L10相FePt奈米線陣列之矯頑磁場遠大於Ni3Fe，故FePt/Cu/Ni3Fe奈米線陣列中之FePt固定層與Ni3Fe自由層之磁性差異性，即形成具功能性之開關元件。藉由此性質合成FePt/Cu/Ni3Fe與FePt/NiO/Ni3Fe多層結構之奈米線，即可觀察巨磁阻(GMR)之現象與垂直式磁性自旋閥效應，而多層L10-FePt奈米線陣列其特性可被應用於一維磁性奈米材料。
FePt nanowires arrays were successfully prepared by electrodeposition into porous anodized aluminum oxide (AAO) templates with pore diameters of approximately 50 nm from a very simple electrolyte. The phase transition of FePt nanowire was from a disorder alloy distribution of fcc to ordered L10 phase after annealing at 700oC in 5% H2/N2, and it was observed by x-ray diffraction approach. FePt nanowires with L10 phase exhibit a large coercivity of 7.5 kOe. Thermal treatment was applied to obtain L10-FePt nanowires with (001) preferential orientation. The coercivity of L10- FePt nanowires is greater than that of Ni3Fe, therefore FePt/Cu/Ni3Fe nanowires exhibited a well-separated switching of the FePt fixed layer and the Ni3Fe free layer. This characteristic can be used to fabricate multi-segment of FePt/Cu/Ni3Fe and FePt/NiO/Ni3Fe nanowires which also can observed the giant magnetoresistance (GMR) and perpendicular magnetic spin valve effect. multi-segment of L10-FePt nanowires prepared by the present process have great potential for one dimension nanomagnetism application.
FePt nanowires arrays were successfully prepared by electrodeposition into porous anodized aluminum oxide (AAO) templates with pore diameters of approximately 50 nm from a very simple electrolyte. The phase transition of FePt nanowire was from a disorder alloy distribution of fcc to ordered L10 phase after annealing at 700oC in 5% H2/N2, and it was observed by x-ray diffraction approach. FePt nanowires with L10 phase exhibit a large coercivity of 7.5 kOe. Thermal treatment was applied to obtain L10-FePt nanowires with (001) preferential orientation. The coercivity of L10- FePt nanowires is greater than that of Ni3Fe, therefore FePt/Cu/Ni3Fe nanowires exhibited a well-separated switching of the FePt fixed layer and the Ni3Fe free layer. This characteristic can be used to fabricate multi-segment of FePt/Cu/Ni3Fe and FePt/NiO/Ni3Fe nanowires which also can observed the giant magnetoresistance (GMR) and perpendicular magnetic spin valve effect. multi-segment of L10-FePt nanowires prepared by the present process have great potential for one dimension nanomagnetism application.
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奈米線, 陽極氧化鋁, 自旋閥, nanowires, anodized aluminum oxide, spin valve