Abstract
Growth in the demand for higher capacity hard disk drives has pushed the requirement for head-media spacing to sub-nanometer levels. The drop in operational clearance makes a head-disk interface more susceptible to potential head-wear and contamination related issues. Such degradation processes are often accompanied by a noticeable shift in the head-disk clearance. Hence monitoring an interface for a spacing change can be helpful in early detection of its imminent failure. In this paper, we present a method to detect the change in head-disk spacing using an embedded contact sensor (ECS). This technique involves the analysis of ECS dynamic response for an interface that is subjected to heater induced spacing modulations. As the head moves closer to the disk surface, the magnitude of the ECS frequency components can be used to determine the ‘characteristic spacing’ which can be used as a metric to detect any physical change for a given interface.
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Acknowledgements
The authors gratefully acknowledge Dr. Raj Thangaraj on his technical expertise on drive contamination related reliability issues and Robert Eaton with his help with HDD testing firmware. They would also like to acknowledge Thomas Nguyen his assistance with the siloxane injection study, Dr. Xiaozhou Ding, for his assistance with the scanning electron microscope, and Mani Soroushpour for providing hard drives for the experiments.
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Rai, R., Bhargava, P., Knigge, B. et al. A method for monitoring head media spacing change in a hard disk drive using an embedded contact sensor. Microsyst Technol 26, 3459–3467 (2020). https://doi.org/10.1007/s00542-020-04911-9
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DOI: https://doi.org/10.1007/s00542-020-04911-9