Current-induced phenomenon on Fe/W(111) and the improvement ofsignal to noise ratio

• Main Authors: Chih Hsiang, 張智翔
• Other Authors: Chien Cheng Kuo
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/30980889176211731360

碩士 === 國立中山大學 === 物理學系研究所 === 99 === In our earlier research, we found the MOKE signal incident from 45 degree would cause perpendicular signal to couple with the longitudinal one. To distinguish the signal from one to another, we arranged 45 degree and 0 degree optical setup for the measurement of longitudinal and perpendicular respectively. However, hysteresis loops are only observed in the longitudinal direction. To measure smaller signal in our experiment, we reduced the noise level by one order and thus improved the signal to noise ratio. It’s ten times better then previous result. Under smaller signal or worse S/N ratio condition, we still measured the MOKE signal. In order to quantitatively analyze the current-induced field, we made a metal coil and try to measure the bias produced by the field. And we injected the reverse current-induced field, , try to counteract the bias of hysteresis loop which is induced by sample current. Besides, we also dosed oxygen on the sample and measured the MOKE signal. There was no change comparing with which is measured in gas-free condition. But we found the coercivity became larger after annealing to 300K, and the current-induced bias in oxygen become smaller.