Tribology of proximity magnetoresistive head–disk interface for 5 Gb/in.2 recording

Abstract

Low fly-height magnetoresistive ͑MR͒ sliders and low glide-height laser-texture thin film disks were introduced to meet the tribological challenges of proximity MR recording, with which an areal density of 5 Gb/in. 2 has been achieved when using the sliders with dual-stripe MR heads and the disks with low-noise media. The 30% pico sliders employed two air-bearing designs with a fly height around 12.5 nm. The thin film disks used superfinish substrates with a glide-avalanche-height falling well below 10.0 nm. In the contact start/stop ͑CSS͒ zones, small crater-shape laser texture bumps were generated to meet both low stiction and low glide-height requirements. An 80 Å thin amorphous nitrogenated carbon was added over the magnetic layers as a protective overcoat. A layer of perfluoropolyether with an additive of phosphazene compounds was applied on the disk surface to improve the reliability of head-disk interfaces. The near contact head-disk interface survived for 20 k-cycle hot/wet and hot/dry CSS tests without wear and high stiction. Twenty-four-hour hot/wet park-stiction values after 20 k CSS cycles were within the acceptable range. Remarkably, thermal-asperity tests showed no hits by using the proximity heads on the ultralow glide-height thin film disks.