Selected topics in disk media analysis

The current trend of increasing media storage density requires more understanding of the head and disk surface/interface. In this paper, the properties of carbon and magnetic layer interface, sub-100A carbon overcoat, lubricants and their additive stability were selected as examples for discussion. Carbon thickness is one of the key factors for design of the head/media interface. It is also crucial for one of the current approaches for increasing the media density via shrinkage of the spacing between head to magnetic alloy. With the current carbon thickness in the sub-100 A range, accurate measurement and understanding of the carbon properties and its interface become a challenge. Various techniques including Time-of-flight secondary ion mass spectrometry, x-ray photoemission spectroscopy, Raman spectroscopy and atomic force microscopy were used to understand the issues. Control of lubricants and their additives is another topic of importance for the current media design. In situ measurement of the lubricant molecular weight on disk media will be discussed.