Understanding the dynamics and instability of a thermal fly-height control (TFC) head slider close to and at touchdown (TD) on a magnetic recording disk is essential for developing a head slider with a clearance of ~ 0.5 nm to enhance the recording density of hard disk drives. This paper presents a theoretical simulation of a practical TD test, performed by continuously increasing the head protrusion according to the TFC power, and demonstrates ideal TD behaviors to be established in design guidelines for an effective head slider–suspension–disk system. The effects of the air-bearing stiffness and magnitude of disk waviness (DW) on the TD behaviors and their repeatability were extensively investigated. Comparison with the experimental TD behaviors of effective head sliders demonstrated that the different TD behaviors at different radial disk positions could be explained by the numerical TD simulation of the DW-excited response of a single-degree-of-freedom slider model. Possible reasons for the discrepancies between the experimental and simulation results in the light contact state were analyzed in detail, and a method of designing the head–disk interface conditions to achieve a head spacing of ~ 0.5 nm was developed. In addition, the deviation from the ideal TD behavior according to the DW magnitude was examined. The TD behavior of a head slider on a disk with a perfectly bonded lubricant was theoretically clarified, and the potential for realizing a head slider with reduced clearance was assessed.

中文翻译：

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实现理想的亚纳米间隙磁头滑块触地行为的热飞高控制滑块触地试验的数值模拟

了解磁记录磁盘上接近和触地时（TD）的热飞高控制（TFC）磁头滑块的动力学和不稳定性对于开发间隙〜0.5 nm的磁头滑块以提高磁记录头的记录密度至关重要硬盘驱动器。本文介绍了实际TD测试的理论模拟，通过根据TFC功率不断增加磁头伸出量来执行，并演示了在有效磁头滑块-悬架-磁盘系统的设计准则中应建立的理想TD行为。广泛研究了空气轴承的刚度和磁盘波纹度（DW）对TD行为及其可重复性的影响。与有效磁头滑块的实验TD行为的比较表明，可以通过单自由度滑块模型的DW激发响应的数值TD模拟来解释在不同径向磁盘位置处的不同TD行为。详细分析了光接触状态下的实验结果与模拟结果之间差异的可能原因，并开发了一种设计磁头-磁盘界面条件以实现〜0.5 nm磁头间距的方法。此外，检查了根据DW量值与理想TD行为的偏差。理论上阐明了磁头滑块在磁盘上具有完美结合的润滑剂的TD行为，并评估了实现间隙减小的磁头滑块的潜力。