Current-Induced Magnetization Switching in Perpendicularly Anisotropy MagnetizedMgO/CoFeB/Ta

• Main Authors: Tzeng Wei Han, 曾威翰
• Other Authors: Chern Gung
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/72521932516986474780

碩士 === 國立中正大學 === 物理學系暨研究所 === 102 === The current-induced switching (CIS) in perpendicular magnetic thin layers and tunnel junctions has recently attracted lots of attention due to the possibility to achieve higher density magnetic random access magnetic memory(MRAM). However, the mechanism of the CIS and the materials dependence is still not clear. In this thesis, we fabricated a series of perpendicular magnetized MgO/CoFeB(1.3 nm)/Ta Hall bar structures with Ta thickness = 1, 1.25, and 5 nm, respectively. We found that the magnetic switching, through the measurement of anomalous Hall voltage, show stronger dependence on the Ta thickness relative to the similar structure with bottom Ta layer. The main effect may be interpreted by a current induced field-like-torque. We will discuss the quantitative critical current density as a function of Ta thickness and also explain why the top Ta layer introduces different effect relative to the bottom Ta layers.