Optimization of Growth and Magnetic Characteristics of TbFeCo-based Perpendicular Maganetic Tunnel Junction

• Main Authors: ZOU,YI-JYUN, 鄒宜均
• Other Authors: CHEN,YUAN-TSUNG
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/7k8ax4

碩士 === 國立雲林科技大學 === 材料科技研究所 === 107 === The present work deals with the preparation of an optimized TbFeCo-based perpendicular Magnetic Tunnel Junction (pMTJ). Significant magnetic properties of TbFeCo magnetic layer are achieved by optimizing the sputtering powers (SPs) of Tb and FeCo during the co-sputtering process. In the experiment, different Tb and FeCo SPs for different deposition time are used to prepare several TbFeCo thicknesses in the /Ta5 nm, thin film structure. The magnetic characteristics viz. saturation magnetization (Ms), coercivity field (Hc) and squareness (Mr/Ms) of such structures, are characterized by Alternating Gradient Magnetometer (AGM) as a function of Tb & FeCo sputtering power. The best results are obtained for 10 nm TbFeCo thickness with SPs of 85 W & 135 W for Tb and CoFe,respectively.It is found that, for spin Hall measurement, SiOx/TbFeCo10 nm/Ta5 nm/MgO4 nm structure gives characteristic Hall curve with large Hall voltage. Further Co40Fe40B20 and Co20Fe60B20 magnetic layers’ thickness are optimized separately for making SiOx/Ta/TbFeCo/MgO/CoFeB/Ta/Ru MTJ structure. The MTJ with Co40Fe40B20 exhibits no PMA irrespective of the different annealing condition. However, MTJ with Co20Fe60B20 deposited at SPs of 85 W and 165 W for Ta and FeCo, respectively and followed by a two-stage annealing at 200℃-1hr-300℃-1hr, shows excellent PMA and double magnetization loop.