超高密度图案化磁记录介质中偶极作用与热辅助磁化研究  

Study on the dipolar interaction and heat assisted magnetization in patterned magnetorecording media of superhigh density

作　　者：唐可[1] 张怀武[2] 

机构地区：[1]西南科技大学材料科学与工程学院,四川绵阳621010 [2]电子科技大学微电子与固体电子学院,四川成都610054

出　　处：《电子元件与材料》2008年第4期73-74,共2页Electronic Components And Materials

基　　金：国家自然科学基金资助项目(No.60490296)

摘　　要：由于记录介质的超顺磁效应,传统的水平磁记录方式已经达到理论极限。为了实现特比(Tb,1Terabit=240bit)级的超高密度存储,各种记录方案正在探索之中,其中图案化介质和热辅助磁记录技术被认为是最有发展潜力的方向,如果将两者结合则记录密度会更高。笔者结合已有的实验数据与前人的理论工作,通过有限差分法求解动力学方程和Monte Carlo随机方法,重点研究了以下几个与图案化介质及热辅助磁化技术有关的问题:(1)针对数值微磁学中矩形网格处理复杂边界时计算精度较低的问题,利用磁体本身的几何对称性和退磁张量的性质,通过在实空间求积分的方法解析地推导了等边三棱柱的退磁张量。根据这一张量表达式,可以得到任意精度的退磁因子,把这一结果应用在微磁学的网格划分当中,可以提高对复杂边界的处理能力。(2)为了能够在数值计算中高效地求出系统中的偶极作用能,解决由于偶极作用长程性带来求和速度收敛缓慢的问题,笔者通过重新定义网格求和方程,并采取分段处理的方法,解决了Lekner求和法中由于对称性降低而导致的奇异性问题,成功地把Lekner求和法从三维周期性边界条件下的库仑作用系统,推广到了二维周期性结构的磁偶极作用系统。应用Lekner求和法,可以高效地处理图案化介质这类规则排列的磁偶极子系统中、偶极作用能的计算问题。(3)为了深入理解偶极作用能对信息位稳定性与信息写入过程的具体影响,为实际设计图案化记录系统时选择合适的图案化介质提供理论指导,笔者通过求解二维系统的动力学方程,研究了有限阵列和周期性边界条件阵列磁性颗粒间偶极作用能对系统静态与动态性质的影响。发现有限阵列的静态磁学性质,诸如剩磁状态、矫顽力等与系统的大小密切相关,而磁化动力学过程则不受系统大小的影响。发现偶�Because of the superparamagnetism in recording media, the traditional longitude magnetorecording technology is close to the theoretical limit. At the same time, patterned media （PM） and heat assisted magnetic recording （HAMR） are regarded as the potential ways to achieve Terabit level ultrahigh area density. In this dissertation, studied were the following problems about PM and HAMR by computer simulations based on the experiment data and previous theoretical work： （1） In order to improve the accuracy in micromagnetic simulation of complex boundary, derived were the point function demagnetization tensor of equilateral triangular prisms in terms of the symmetry of the magnetic body and a theorem about demagnetization tensor. One can obtain the demagnetization factors with any accuracy of equilateral triangular prisms by numerically integrate this expression. This result can be used in micromagnetic discretization and improve the accuracy of calculation. （2） In order to deal with the long range effect of dipolar interaction efficiently, the Lekner summation method was extended from three dimensional Coulomb systems to two dimensional magnetic dipolar systems successfully. The Lekner method can be used to sum the dipolar interaction energy in PM and other regular arrays efficiently and can be used in other randomly distributed systems combined with other summation techniques. （3） On solving the dynamics equations of two dimensional systems, studied were the dipolar interaction in finite arrays and periodic arrays to understand the effects of dipolar interaction energy on the writing process and stability of the reconding bits. It is found that the quasistatic properties, such as remanence and coercivity are influenced by the size of finite arrays. On the contrary, the reversal modes are only determined by the dipolar interaction strength. For the easy plane anisotropy, the dipolar interaction strength determines three reversal modes, which are coherent rotation, nucleation and the tran

关 键 词：电子技术 图案化介质 Lekner求和法 偶极作用能 热辅助磁化强度 

分 类 号：TN4[电子电信—微电子学与固体电子学]