Study of Switching Mode of Magnetization in Synthetic Antiferromagnet of CoFeB/Ta/CoFeB

• Main Author: 王介平
• Other Authors: 洪連輝
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/04184625799766355023

碩士 === 國立彰化師範大學 === 物理學系 === 97 === In this study, we use the synthetic antiferromagnet (SAF) of CoFeB(5 nm)/Ta(t nm)/CoFeB(5 nm) and changing the different nonmagnetic layer (Ta) thickness to discuss the RKKY oscillation behavior of the ferromagnetic coupling and the antiferromagnetic coupling. The ellipse dots are 500 nm and 800 nm ,and the L/W ratio of ellipse dots are 1, 1.5 and 2. We compare the switching mode of magnetization in the CoFeB monolayer, the ferromagnetic coupling of SAF structure and the antiferromagnetic coupling of SAF structure. The dot arrays are patterned in an area of 80 μm × 80 μm utilizing electron beam lithography and lift off technique. The hysteresis loops are measured by magneto-optical Kerr effect (MOKE) in thin films and dot arrays. We observe good antiferromagnetic coupling when Ta is 1.0 nm, and good ferromagnetic coupling when Ta is 2.0 nm. The SAF structure is easier switching than monolayer in the same array size. In the dot arrays, when aspect ratio are larger, the coercivity is increasing and the switching field is decreasing.