| Summary: | 碩士 === 國立雲林科技大學 === 材料科技研究所 === 104 === The magnetic structures in this study were made by high vacuum sputtering system. We focused on the Co40Fe40B20 films with perpendicular magnetic anisotropy ,and used it to fabricate the orthogonal magnetic tunnel junctions (MTJs). The magnetic properties of the thin films were tuned by varying the Co40Fe40B20 thickness and the annealing temperature. The Ta/Co40Fe40B20/MgO/Ta structure showed that thickness of Co40Fe40B20 from 0.9 nm to 1.7 nm had perpendicular magnetic anisotropy, and coercivity can as high as 33 Oe. The free layer MgO/NiFe/MgO/ structure ,showed that thickness of NiFe from 2 nm to 6 nm had no significant differences, and the coercivity all about 1 Oe. Moreover we investigated the exchange-coupling fields of Co20Fe60B20/Ru/Co20Fe60B20/IrMn synthetic antiferromagnetic (SAF) structures,when the thickness of Ru is 0.9 nm. However ,when the thickness of Ru war increase to 1.1 nm, it revealed that no exchange-coupling fields. When the annealing time was long enough, the anisotropy SAF layer was declining, but the vertical anisotropy of Co40Fe40B20 was increased. According to observation of transmission electron microscopy (TEM), it is found that each interface is not clear because the annealing treatments induce atomic diffusion between the boundary. When the device size is 5 µm × 5µm,the MR ratio is 0.84%. The resistance is decreased when the input current varied from 100 nA to700 nA.
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