Zero magnetostriction Fe-Co-Cr magnetic recording media

Abstract

A low or zero magnetostriction ferromagnetic alloy is used for a magnetic recording medium. The alloy is (Fe.sub.y Co.sub.1-y).sub.1-x Cr.sub.x where y (Fe) is preferably 15-23 atomic percent of the FeCo part of the alloy. The value of x (Cr) is 7-20 atomic percent of the alloy and the remainder 1-x (FeCo) is 83-92 atomic percent of the alloy. The maximum ranges of the composition of the alloy are about as follows: Fe - 8-24 atomic percent Co - 56-83 atomic percent Cr - 7-20 atomic percent The material is adapted for use at room temperature below the Curie temperature of the specific alloy employed. When y (Fe) is 13 at. % and x (Cr) is 7 at. % the magnetostriction remains at zero, but the material is not corrosion resistant and thus it is useful for magnetic recording applications only where corrosion is not a problem. Thus the percentage of Cr must be within the range from 7-17 atomic percent. Above about 17 atomic percent of Cr, the saturation magnetization of the films falls off rather precipitously and it reaches zero at about 20 atomic percent of Cr. This has been shown for Fe.sub.48 Co.sub.52 in combination with percentages of Cr added to that FeCo mixture. These alloys are useful for magnetic recording media because of their low magnetostriction which increases the capacity to have assurance as to the location of a bit of information on a medium.

Dependencies are inferred from the claim text.