Transient Characteristics of Nanoscale Air Bearings Subjected to Joule Heating

Transient characteristic of heat exchange between closely positioned bodies has become an important issue owing to the continuous miniaturization of many technologies such as high-density magnetic recording, integrated circuits, and atomic force microscopy. We experimentally and numerically study the transient characteristics of nanoscale air bearings subjected to Joule heating of a nearby heating element in hard disk drives. Our results reveal that the response consists of multiple characteristic times, and at least two terms (τ ₁ = 162 μs and τ ₂ = 23 μs) are required to capture the transient response. We present a one-dimensional analytical model that provides a better understanding of the nature of the transient characteristics and an efficient way to obtain their trends and bounds. Our model may also explain the much faster response due to laser heating observed in heat-assisted magnetic recording system.