Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/47613
標題: 場冷卻及氧含量對鎳鈷/鎳鈷氧化物雙層薄膜之交換偏壓特性研究
Effects of the Cooling Field and the Oxygen Content on Structures, Magnetic, and Magnetotransport Properties of NiCo/(Ni,Co)O Bilayers
作者: 林克偉
關鍵字: 鎳鈷/鎳鈷氧化物雙層薄膜;NiCo/(Ni;材料科技;交換偏壓;磁電阻;雙離子束濺鍍技術;應用研究;Co)O bilayers;exchange bias;magnetoresistance;ion-beamdeposition technique
摘要: 
The shift of a magnetic hysteresis loop away from zero field in a thin film systemcomposed of a ferromagnet (FM) coupled to an antiferromagnet (AF) is calledexchange bias. It is typically accompanied by an enhanced coercivity when theFM/AF bilayer is field-cooled below the Neel temperature (TN) of the AF. The loopshift, Hex, depends on the exchange coupling energy and the thickness of theferromagnetic layer. The exchange bias effect has been extensively studied during thelast decade due to its applications in spin valves for the ultra high density magneticrecording.Our previous works [1,2] indicate that the exchange bias in FM/AF systemsstrongly depends on the structures of antiferromagnetic oxides (eg. CoO, Fe2O3) forthe same type of ferromagnetic layer (NiFe). In this proposal, the NiCo/(Ni,Co)Obilayers will be prepared by a dual ion beam deposition technique [3]. The NiFe toplayers will be grown by directly sputtering the commercial NiCo target from theKaufman ion source. The (Ni,Co)O bottom layer will be prepared in the presence of amixed Ar/O2 beam in the End-Hall ion source.We will focus on the structures, magnetic, and magnetotransport properties ofNiCo/(Ni,Co)O bilayers. In the first year, the NiCo/(Ni,Co)O bilayers will beprepared and the surface morphology, structural and magnetic properties will beinvestigated. In the second year, effects of the cooling field in NiCo/(Ni,Co)O bilayerswill be studied at temperature down to 10 K. In the third year, the magnetotransportproperties (electrical resistance and magnetoresistance) of NiCo/(Ni,Co)O bilayerswill be investigated both at room temperature and at low temperature. Magneticproperties of these NiCo/(Ni,Co)O bilayers will be simulated by LLG software basedon the micromagnetics.[1] K.-W. Lin, P.-H. Ko, Z.-Y. Guo, H. Ouyang, and J. van Lierop, J. Nanosci.Nanotech., 7, 265 (2007).[2] K.-W. Lin , J.-Y. Guo, C.-Y. Liu, H. Ouyang, J. van Lierop, N . N. Phuoc, and T.Suzuki, Phys. Stat. Sol. (a), 204, 3991 (2007).[3] H. Ouyang, K.-W. Lin, C.-C. Liu, S.-C. Lo, Y.-M. Tzeng, Z.-Y. Guo, and J. vanLierop, Phys. Rev. Lett. 98, 097204 (2007).

當鐵磁層與反鐵磁層之間產生交互作用造成磁滯曲線之偏移,此稱之為交換偏壓。當鐵磁/反鐵磁雙層薄膜由尼爾溫度場冷至量測溫度亦經常伴隨矯頑磁力之增加。交換偏壓場與交換耦合能量及鐵磁層之厚度有關,此交換偏壓效應近年來廣泛被研究主要由於超高密度磁紀錄材料中自旋電子閥門之應用。先前研究[1,2]顯示,鐵磁/反鐵磁薄膜之交換偏壓與反鐵磁層氧化物之結構(如氧化鈷,氧化鐵)有很密切之關係(使用相同之鐵磁層鎳鐵薄膜)。本研究利用雙離子束濺鍍系統[3]製備鎳鈷/鎳鈷氧化物雙層薄膜。其中鎳鈷薄膜由Kaufman離子源直接濺鍍鎳鐵靶材,而鎳鈷氧化物薄膜由End-Hall 離子源之氧氣撞擊基材並動態氧化鎳鈷原子而得。本研究第一年主要製備鎳鈷/鎳鈷氧化物雙層薄膜並探討其表面形態、結構與磁性質。第二年主要探討氧含量及場冷卻對鎳鈷/鎳鈷氧化物雙層薄膜之交換偏壓與矯頑磁力對溫度之影響。第三年主要探討鎳鈷/鎳鈷氧化物雙層薄膜室溫與低溫之磁電傳輸性質。鎳鈷/鎳鈷氧化物雙層薄膜的磁性質實驗結果將與利用電腦軟體模擬(LLG)的結果相互比較及印証。[1] K.-W. Lin, P.-H. Ko, Z.-Y. Guo, H. Ouyang, and J. van Lierop, J. Nanosci.Nanotech., 7, 265 (2007).[2] K.-W. Lin , J.-Y. Guo, C.-Y. Liu, H. Ouyang, J. van Lierop, N . N. Phuoc, and T.Suzuki, Phys. Stat. Sol. (a), 204, 3991 (2007).[3] H. Ouyang, K.-W. Lin, C.-C. Liu, S.-C. Lo, Y.-M. Tzeng, Z.-Y. Guo, and J. vanLierop, Phys. Rev. Lett. 98, 097204 (2007).
URI: http://hdl.handle.net/11455/47613
其他識別: NSC97-2221-E005-021-MY3
Appears in Collections:材料科學與工程學系

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