Investigation of Spin Transport in Low Dimensional Structures

• Main Authors: Jun-Yu Ou, 歐俊裕
• Other Authors: J. C. Wu
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/30237884120807683255

碩士 === 國立彰化師範大學 === 物理學系 === 93 === Substantial critical current density is required for current driven switching in patterned magnetic devices, giving rise to an ambiguity in the interpretation using joule heating and/or spin transfer torque effect alone. Thus, we have attempted to identify these possible mechanisms by adopting a notched magnetic multilayer strip and introduce high ambient temperature and/or high dc current density. The device consists of one micron wide of Py-25nm/Cu-2.5nm/Py-5nm and Py-25nm /Cu-7.0nm/ Py-5nm tri-layer pseudo spin valve strip with 0.5 μm width of symmetrical notch in the middle. The low field differential MR curves are measured at various ambient temperatures and with different dc current at room temperature. Notice that the MR curves reveal extra switching in the soft layer with dc current density above 1.54x1011A/m2, whereas the MR curves maintain single switching at ambient temperatures up to 323 K. A comparison between the ambient temperature and Joule heating has led to a better understanding in resolving the key mechanism for magnetization reversal in the patterned devices.