RESEARCH ON PERPENDICULAR SINGLE-POLE-TYPE HEAD FOR ULTRA HIGH DENSITY MAGNETIC RECORDING BY USING NUMERICAL ANALYSIS

本文对垂直记录中最重要的部件之一单极头进行了数值分析。最初的目标设定为每平方英寸1太比特（太比特/平方英寸）。我们已经研究了SPT头部结构来达到这个密度和更高的密度。得到的结果如下：基于有限元模拟研究了400 Gb/in^2的单杆式封头设计。给出了产生足够的面密度场所需的条件。为了达到这个密度，我们考虑了各种介质，并从LLG模拟中得出了写入磁道宽度、擦除频带、信噪比和写入位模式。比较了离散磁道介质和连续磁道介质的记录性能。拖尾护罩增加头部场梯度，导致更清晰的过渡和更高的信噪比。确定两种介质的最佳尾随屏蔽间隙为30 nm。使用这种写磁头，在相邻磁道无擦除的条件下，离散磁道介质的信噪比在1700 kfci的线性密度下比连续介质高1.5 dB。对整个磁性材料进行了微磁处理的LLG计算。研究了不同极尖结构下的记录场。发现存在一个最佳的非零喉道高度，使记录场强最大化。在获得较大的记录场梯度方面，发现尾随屏蔽是有效的。进行了热分析，推导了不同条件下SPT封头元件的温升。由于商业软件的缺陷，没有对温度升高引起的变形分析进行研究。

In this scientific research, single-pole-type head, one of the most important components in perpendicular recording, was investigated by numerical analysis. The original goal was set at 1 Terabits per square inch (Terabits/in^2). We have investigated the SPT head structure to achieve this density and beyond. Here are the results obtained :1.A single-pole-type head design for 400 Gb/in^2 based on FEM simulations was investigated. The conditions required to generate a sufficient field for this areal density were shown. To reach this density various media were considered and written track widths, erase bands, SNR's, and written bit patterns were derived from LLG simulations.2.The recording performance of discrete track media and continuous media was compared. Trailing shields increase the head field gradient, leading sharper transitions and higher SNR. The optimum trailing shield gap was determined to be 30 nm for both types of media. Using such a write head and subject to the condition of no adjacent track erasure the discrete track media SNR was 1.5 dB higher than the continuous media at a linear density of 1700 kfci.3.LLG calculation that treats the whole magnetic material micromagnetically was performed. The recording fields are investigated for various pole tip structures. It was found that an optimum non-zero throat height exists that maximizes recording field strength. Trailing shield was found to be effective with regard to obtaining a larger recording field gradient.4.Thermal analysis was carried out and the temperature rise in the SPT head element derived for various conditions. Deformation analysis due to temperature rise was not investigated because of commercial software bugs.