Low noise magnetic thin film longitudinal media

Claim 1

A device for storing magnetically readable data, including: a substrate having a substantially planar substrate surface; a crystalline underlayer deposited upon said planar base surface to a thickness within the range of from about two hundred to six thousand angstroms, said underlayer having a substantially uniform crystallographic orientation to control the orientation of crystals epitaxially grown upon the underlayer, said underlayer comprised of individual grains having average diameters in the range of from about one hundred to one thousand angstroms; and a crystalline recording underlayer formed by epitaxial growth of a metallic thin film upon said underlayer, the crystallographic orientation of said recording layer being determined by the crystallographic orientation of said underlayer whereby the axes of easy magnetization of the crystals comprising said recording layer are substantially aligned in a plane parallel to said planar base surface, said recording layer being generally parallel to said substrate layer and comprised of individual grains of said recording layer, and of continuous and interconnected interstitial regions between adjacent grains whereby each grain is substantially isolated from its adjacent grains in order to significantly reduce exchange coupling interactions between neighboring grains, with the width of any one of said interstitial regions separating adjacent grains being at least three times the crystal lattice constant of the alloy comprising the grains, said interstitial regions comprising at least ten percent of the recording layer, said recording layer being formed to a thickness in the range of from about three hundred angstroms to about one thousand angstroms; wherein said underlayer consists essentially of at least one of the following elements: chromium, molybdenum, tungsten, bismuth, niobium, tantalum, vanadium, and titanium; and wherein said recording layer consists essentially of one of the following alloys: (a) cobalt at up to ninety-five atomic percent, chromium at from five to eighteen atomic percent, and a third component at from one to twenty atomic percent and consisting of at least one of the following elements: tungsten, tantalum, molybdenum, vanadium, niobium, platinum, bismuth, zirconium, and hafnium; (b) cobalt at up to ninety-three atomic percent, nickel in the range of from five to forty atomic percent, and a third component from two to twenty atomic percent and consisting essentially of at least one of the following elements: chromium, tantalum, tungsten, zirconium and platinum; and (c) cobalt and from two to thirty-five atomic percent of a second component consisting essentially of at least one of the following elements: sumarium, yttrium, chromium, nickel, selenium and tungsten.

Claim 2

A device for storing magnetically readable data, including: a substrate having a substantially planar substrate surface; a crystalline underlayer deposited upon said planar base surface to a thickness within the range of from about two hundred to six thousand angstroms, said underlayer having a substantially uniform crystallographic orientation to control the orientation of crystals epitaxially grown upon the underlayer, said underlayer comprised of individual grains having average diameters in the range of from about one hundred to one thousand angstroms; and a crystalline recording underlayer formed by epitaxial growth of a metallic thin film upon said underlayer, the crystallographic orientation of said recording layer being determined by the crystallographic orientation of said underlayer whereby the axes of easy magnetization of the crystals comprising said recording layer are substantially aligned in a plane parallel to said planar base surface, said recording layer being generally parallel to said substrate layer and comprised of individual grains of said recording layer, and of continuous and interconnected interstitial regions between adjacent grains whereby each grain is substantially isolated from its adjacent grains in order to significantly reduce exchange coupling interactions between neighboring grains, with the width of any one of said interstitial regions separating adjacent grains being at least three times the crystal lattice constant of the alloy comprising the grains, said interstitial regions comprising at least ten percent of the recording layer, said recording layer being formed to a thickness in the range of from about three hundred angstroms to about one thousand angstroms; wherein said underlayer consists essentially of at least one of the following elements: chromium, molybdenum, tungsten, bismuth, niobium, tantalum, vanadium, and titanium; and wherein said recording layer consists essentially of one of the following alloys: (a) cobalt at up to ninety-five atomic percent, chromium at from five to eighteen atomic percent, and a third component at from one to twenty atomic percent and consisting of at least one of the following elements: tungsten, tantalum, molybdenum, vanadium, niobium, platinum, bismuth, zirconium, and hafnium; (b) cobalt at up to ninety-three atomic percent, nickel in the range of from five to forty atomic percent, and a third component from two to twenty atomic percent and consisting essentially of at least one of the following elements: chromium, tantalum, tungsten, zirconium and platinum; and (c) cobalt and from two to thirty-five atomic percent of a second component consisting essentially of at least one of the following elements: sumarium, yttrium, chromium, nickel, selenium and tungsten.