Perpendicular Magnetic Recording Media with Si/NiFe/FeCoB Crystalline Soft Magnetic Underlayer

Abstract

Reducing the thickness of th e Ru i ntermediate layer (IML) is one of th e most effective ways of realizing highdensity hard disk drives and magnetic tapes. Use of a crystall ine soft magnetic underlayer (SUL) has the advantage of r educing the IM L th ickness an d r esults in better (001) or ientations in both Ru IM L an d CoPtCr-SiO2 recording layer (RLs). Ru or Si/NiFe seed lay ers impr ove th e deg ree of FeCo(110) or ientation in th e SU L an d th e c-axis orientation of the RL. An Ru/FeCoB layer and an Si/NiFe/FeCoB layer were compared for crystalline orientation and magnetic properties. The integr ated intensity of th e (002) diffraction peak of CoPtCr had an almost constant value even when the thickness of the Ru IML was changed from 30 nm to 2 nm. The coercivity and squareness ratio in the direction perpendicular to the of recording layer maintained the same value even when reducing the thickness of the Ru IML was reduced from 30 nm to 5 nm. Key words: perpendicular magnetic recording media， crystalline soft magnetic underlayer， Ru intermediate layer， (110) orientation of bcc-FeCo， (001) orientation of hcp-Ru