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Abstract

A method of forming an isotropic texture having a selected summit density and surface roughness in a selected inner-diameter annular zone of a thin-film medium substrate having a polished metal coating on the substrate. The zone is selectively exposed to a chemical etchant, under etchant strength, temperature, and exposure time, until the selected summit density and roughness are achieved. In a preferred embodiment, the etching conditions are selected to produce a summit density between about 500-20,000/mm.sup.2, and an arithmetic mean roughness value between about 20-70 .ANG. in the inner zone, and a substantially reduced roughness value in an annular, isotropically textured outer-diameter zone of the coating. A thin-film medium formed on the substrate is suitable for near-contact recording.

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