The Study of Tunneling Magnetoresistance in 〔Co/AlOX/Ni80Fe20〕

• Main Authors: J. W. Lee, 李智文
• Other Authors: L. H. Chen
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/84316090770155626152

碩士 === 義守大學 === 材料科學與工程學系 === 87 === The tunneling magnetoresistance and magnetization behavior of 【Ta（50 A）/Co（150 A）/Al（10 A~40 A）OX/Ni80Fe20（150 A）/Ta（50 A）】 films with AlOX insulator has been studied in this work. The films were prepared by d.c. magnetron sputtering and the AlOX oxide layer was obtained by oxidation of Al by plasma oxidation and subsequent O2 oxidation. The maximum MR ratio is 1.9﹪and 2.8﹪at room temperature and 15K, respectively, for 【Ta（50 A）/Co（150 A）/Al（20 A）OX/Ni80Fe20（150 A）/Ta（50 A）】 films in which the 20 A thick Al layer is oxided in O2 for 1.5 hr. For films with Al layer oxided for 3 and 5 hr, both of the mean surface roughness and AlOX layer thickness increase, This makes the MR ratio of films decade. For film with Al layer oxided for 0 hr and 0.5 hr, the Al layer incompletely oxided. The remained Al phase in films behaves as a conductor and the MR ratio is low. Decreasing the Al layer thickness to 10 A induces the formation of pin-hole or other defects in films. This again affects the MR behavior. Similarly, for the film with Al layer thickness of 40 A, the co-existence of remained Al phase as well as the higher mean surface roughness causes the MR ratio to be lower than that for film with Al layer thickness of 20 A.