【作者】 董凯锋；

【导师】 杨晓非；

【作者基本信息】 华中科技大学 ， 微电子学与固体电子学， 2009， 博士

【摘要】 光磁混合存储技术可以突破铁磁材料超顺磁极限的限制，极大地提高硬盘记录密度。它利用铁磁材料矫顽力的温度特性，采用激光辅助热磁写入，信号读出则采用高灵敏度的巨磁阻磁头检测磁通方式来进行。实现光磁混合存储的关键之一是光磁混合记录介质的研究和开发，本文围绕FePt基光磁混合记录介质的研究和制备，完成的主要研究工作包括：针对光磁混合记录的特点和要求，采用射频磁控溅射方法制备出了不同系列的FePt薄膜，制备的薄膜通过真空退火热处理后形成了L1₀有序结构，测量并分析了溅射态和经不同条件退火处理后薄膜的物性及微观结构特性，主要包括：不同膜层厚度以及Ag底层对FePt单层薄膜垂直取向的影响；不同退火冷却速率和不同退火时间对FePt薄膜磁性能的影响；不同膜层结构的[Fe/Pt]_n和[FePt/Ag]₁₀多层膜磁性能研究；Ni掺杂对FePt磁性能和居里温度的影响。测试结果表明：制备的FePt单层和Ag/FePt双层薄膜具有良好的垂直取向；退火过程中的冷却速度能够显著影响剩磁矩形比；Fe/Pt多层膜能有效降低FePt薄膜的有序化温度；采用Ni掺杂的方法能有效降低FePt薄膜的居里温度。采用微磁学方法，模拟了FePt薄膜的磁化翻转过程，描述了磁化翻转过程中不同时刻的磁矩分布情况，研究了薄膜垂直矫顽力随角度θ的变化关系（θ为易磁化轴和外场之间的夹角），以及矫顽力随粒径变化关系；模拟了[FePt/X]₁₀（其中X为非磁性材料）多层膜中X层厚度的变化对多层膜矫顽力的影响；在此基础上，研究了粒径对过渡区噪声参数的影响，所研究的过渡区噪声参数包括过渡区宽度、垂直于记录轨道方向关联长度和位置偏移参数。模拟结果表明：FePt单层薄膜的磁化翻转符合SW模型；随着晶粒尺寸的增大，薄膜矫顽力逐渐降低，过渡区噪声逐渐增大。更多还原

【Abstract】 Optical-magnetic hybrid recording is a novel kind of super-high density information storage method that can break through the super-paramagnetic limit and further increase the recording density as well as the writing and reading data rates of hard disk drives （HDD）. It takes advantages from MO and magnetic recording methods. The message writing is by laser-assisted thermal magnetic recording and message reading is by magnetic flux detection with high sensitive GMR sensors. The study about optical-magnetic hybrid recording media is one of the key technologies for its application. In this dissertation, there are mostly tow parts studying on the FePt perpendicular recording media for hybrid recording surround the recording media and recording model.Experimentally, a series of FePt thin films were deposited by RF magnetron sputtering, and the L1₀-FePt films were obtained after the as-deposited samples were subjected to vacuum annealing. The physical properties and microstructure of both as-deposited and annealed thin films were measured. The experiment part includes the study on the perpendicular orientation of FePt single layer films and the Ag/FePt films; the research on the magnetic properties of the [Fe/Pt]_n and [FePt/Ag]₁₀ multilayer films with different structure; the effect of the different cooling rate and different annealed time on the magentic of FePt films and the effect of Ni doping on the magnetic and the Curie temperature of FePt films. The results shows that: the perpendicular orientation FePt single layer films and the Ag/FePt films have been successfully fabricated; the remanence squareness Mr/Ms of the film with the nature cooling process is bigger than that with the fast cooling process; the Fe/Pt multilayer structure can effectively reduce the ordering temperature of FePt film; Ni doping can effectively reduce the Curie temperature of FePt.Theoretically, Using micromagnetic to simulate the magnetization reversal mechanism in FePt films, and describe the distribution of magnetic moments at different steps during the magnetization reversal, and study the angular dependence of coercivity and the effect of grain size on the coercivity; Simultaneously, This part investigates the effect of grain size on the transition noise performance including transition length Cross Track Correlation Length and Position Jitter. The simulation results shows that: the micromagnetic simulation angular dependence of coercivity reveals a Stoner-Wohlfarth mode. As the grain size increases, the coercivity gradually reduces and the transition noise increases.更多还原