基于内嵌式热传感器的磁头/磁盘界面近场热效应研究

In current hard disk drives with high recording density, the flying height of the TFC slider is controlled on the order of 1 nm by using thermal control techniques. For the next generation of hard disk drives, the temperature on HAMR disk surface will reach up to around 600~700℃. The small clearance and high temperature at the head disk interface make a great increase in the near-field thermal radiation and convection. The thermal effects become to be important for controlling the flying height of the slider and the temperature distribution at the head disk interface. However, the analysis and test methods of the near-field thermal radiation and convection is still needed to be improved. In this study, the near-field thermal radiation and convection at the head disk interface will be studied based on the embedded thermal sensor techniques. The thermal analysis model is built for the embedded thermal sensor, considering the coupling effects of electric heating, thermal radiation and convection at the head disk interface. The thermal response of the embedded thermal sensor to the hydro-thermal-mechanical coupling effect of head disk interface is analyzed. The relationship between the temperature of the embedded thermal sensor and the thermal effects in the sub-nano scale clearance at the head disk interface is illuminated. According to the study, the thermal effects and the clearance at the head disk interface could be accurately tested and analyzed. This project will make a great contribution to the development of next generation hard disk drives for both of the theoretical research and practical applications.

现代超高密度硬盘中磁头的最小飞高在热控作用下达到亚纳米级，新一代磁盘在激光热辅助控制作用下达到600~700℃的局部高温，导致磁头/磁盘界面的微间隙近场热辐射和对流传热量急剧升高，成为控制界面温度和磁头飞高的重要因素，而目前磁头/磁盘界面微间隙状态下近场热辐射和热对流行为的分析与测试体系尚不完善。针对这一学术前沿与难题，本项目基于内嵌式微型热传感器检测技术，开展磁头/磁盘界面亚纳米级微间隙状态下近场热辐射及热对流行为研究；建立内嵌式微型热传感器在热电效应、近场热辐射和微间隙热对流协同作用下的热响应分析模型，阐明磁头/磁盘界面的热-流-结构耦合作用对微型热传感器热响应的影响机理；揭示内嵌式微型热传感器的温度响应与亚纳米级微间隙界面的近场热效应之间的关系规律，为磁头/磁盘微间隙界面状态的准确检测提供依据。本项目研究为发展新一代超高密度硬盘建立基础，具有重要的理论意义和应用价值。

磁头/磁盘界面热效应成为现代超高密度硬盘的核心问题之一，决定了硬盘的存储密度和使用可靠性，而近场热辐射和热对流行为是决定磁头/磁盘界面热效应的核心因素。目前微型热传感器技术已经用于磁头/磁盘界面接触状态检测，而对磁头/磁盘界面微间隙状态的检测体系尚不完善，主要是因为微型热传感器的温度响应与微间隙界面的近场热辐射及近场热对流之间的关系规律尚不明确。本项目基于内嵌式微型热传感器检测技术，展开了磁头/磁盘微间隙界面近场热效应的研究，主要包括：1）研究了磁头在热阻单元通电加热作用下的热结构响应，分析了磁头/磁盘界面的气浮力，并结合磁头的飞行姿态和热变形，获得了气体轴承在稳态飞行过程中和动态启停过程中的界面间隙；2）研究了磁头/磁盘界面气浮轴承的热对流行为和微间隙状态下的近场热辐射行为，揭示了磁头/磁盘界面近场热效应与微间隙界面状态之间的关系规律；3）亚纳米级微间隙状态下内嵌式微型热传感器的温度响应分析，建立了内嵌式微型热传感器在磁头/磁盘界面电热效应、近场热辐射和近场热对流耦合作用下的热响应分析模型，研究了微型热传感器的温度响应，并通过DHT-2 Spin Stand硬盘试验测试系统，对微型热传感器热响应分析进行了验证。通过本项目研究，阐明了微间隙状态下的近场热辐射和热对流对磁头/磁盘界面热效应的影响规律，揭示了磁头/磁盘微间隙界面的热-流-结构耦合作用机理，获得了内嵌式微型热传感器的温度响应，建立了微间隙界面近场热效应的分析与检测体系，为实现磁头/磁盘界面间隙状态检测提供了定量依据，从而为超高密度硬盘的可靠性研究提供了坚实基础。