Research on Flying Characterisics of Flying Head Sliders with Ultra-thin Spacings

本研究利用“直接模拟蒙特卡罗（DS MC）”技术和广义气膜润滑方程“分子气膜润滑（MGL）方程”，对超高密度磁记录用超薄间距浮动磁头滑块的浮动特性进行了研究。首先，开发了用于润滑特性基本分析的基本二维DSMC程序，然后对纳米间距阶梯型气体滑动轴承进行了基本模拟分析，并与基于BGK模型的MGL分析进行了比较。以边界速度U和间距比ho/hi（hi：入口间距，ho：出口间距）为参数，对阶梯型滑块的压力分布进行了数值计算。结果表明，DSMC方法的结果与MOL分析的结果一致，除了在阶跃位置。其次，将DSMC程序推广到具有表面粗糙度的三维分子气膜润滑问题，并与MGL结果进行了比较。这些结果导致的平均流量模型的润滑分析与表面粗糙度，这是非常重要的近接触磁头的未来记录系统。

This research project investigated flying characteristics of flying head sliders with ultra-thin spacings for ultra high density magnetic recording, by the use of "direct simulation Monte Carlo (DS MC)" technique and the generalized gas film lubrication equation called "Molecular Gas-film Lubrication (MGL)" equation. First, basic 2-dimensional DSMC programs for fundamental analyses of lubrication characteris tics were developed, and then basic simulations for step-type slider gas bearings with nanometer spacings were analyzed and compared with BGK-model-based MGL analyses. Pressure distributions were numerically calculated for the step-type sliders with boundary velocity, U, and spacing ratio, ho/hi (hi : inlet spacing, ho : outlet spacing), as parameters. It is revealed that the results of the DSMC method agrec well with those of the MOL analyses almost everywhere except at the step position. Second, the DSMC program was extended to the 3-dimensional molecular gas-film lubrication problems with surface roughnesses and the basic characterisitics are compared with MGL results. These results lead to the average flow model for the lubrication analyses with surface roughnesses, which is very important for near-contact magnetic heads for future recording systems.