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Large Perpendicular Magnetic Anisotropy in Co/Ru Multi-layered Structures

IP.com Disclosure Number: IPCOM000122535D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Parkin, S: AUTHOR [+2]

Abstract

Disclosed is a new multilayered system with intrinsically high perpendicular magnetic anisotropy, which could be a potential candidate for both magnetic recording and reversible magneto-optical recording.

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Large Perpendicular Magnetic Anisotropy in Co/Ru Multi-layered Structures

      Disclosed is a new multilayered system with intrinsically
high perpendicular magnetic anisotropy, which could be a potential
candidate for both magnetic recording and reversible magneto-optical
recording.

      The preliminary demonstration of the present invention has been
carried out for multilayered Co/Ru films which were fabricated by DC
magnetron sputtering onto Si (111) substrates in an Argon gas
atmosphere of 3.25 mTorr.  The Co and Ru layer thicknesses were
varied onto a 100 Angstrom thick Ru underlayer.  In addition, an
overlayer of 50 Angstrom thick Ru films was deposited to protect the
superlattice from oxidation, although later studies have established
that considerably thinner Ru layers have adequate corrosion
resistance.

      The figure shows the dependence of the perpendicular magnetic
anisotropy on Co thickness for the various Ru thicknesses, which was
obtained by torque measurement in fields up to about 20 kOe.  For Co
thicknesses larger than about 5 Angstroms, the perpendicular magnetic
anisotropy is positive for 12 and 16 Angstrom Ru thicknesses.  The
values of the anisotropy constant are of the order of 106 erg/ccCo,
which is the same order of magnitude as single crystal hcp Co.  For
less than 5 Angstrom Co thicknesses, the multilayered films have in-
plane magnetic anisotropy.

      This is the first report of the perpendicularly magnetized
Co/Ru mul...