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Novel Micromagnetic Particles

IP.com Disclosure Number: IPCOM000109568D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 2 page(s) / 89K

Publishing Venue

IBM

Related People

Demuth, JE: AUTHOR [+2]

Abstract

Disclosed is a class of novel magnetic microstructures consisting of a fullerene molecule with a coating of a magnetic metal. The fullerene molecule, for example, C60, is used as a nucleation center for the growth of the magnetic metal. This produces magnetic particles of uniform size and controlled shape. Uniform particles are important in magnetic media so that the switching fields of all the particles are the same for good square loop properties. A method for making magnetic particles having a uniform size and structure consists of the steps of selecting a substrate of one or more fullerene molecules C60, C70 or C76 and nucleating a magnetic layer of a magnetic material on said substrate whereby a particle is formed having fullerene in the center and an outer shell of magnetic material.

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Novel Micromagnetic Particles

       Disclosed is a class of novel magnetic microstructures
consisting of a fullerene molecule with a coating of a magnetic
metal.  The fullerene molecule, for example, C60, is used as a
nucleation center for the growth of the magnetic metal.  This
produces magnetic particles of uniform size and controlled shape.
Uniform particles are important in magnetic media so that the
switching fields of all the particles are the same for good square
loop properties.  A method for making magnetic particles having a
uniform size and structure consists of the steps of selecting a
substrate of one or more fullerene molecules C60, C70 or C76 and
nucleating a magnetic layer of a magnetic material on said substrate
whereby a particle is formed having fullerene in the center and an
outer shell of magnetic material.  The resulting particle is suitable
for use in magnetic recording media.  A method for making these
particles having a uniform size and structure consists of dissolving
cobalt carbonyl, Co2(CO)8, and fullerene C60, C70 or C76 in a solvent
(toluene) to form a solution, heating the solution to a predetermined
temperature (100oC) to decompose the cobalt carbonyl and deposit Co
in the surface of a plurality of fullerene molecules.  Fullerene
molecules provide favorable nucleation sites.  In order to deposit Fe
or Ni and their alloys with Co, the material dissolved  is selected
from a group consisting of cobalt carbonyl, ferrocarbonyl, and nickel
carbonyl or mixtures thereof with fullerene, C60, C70 or C76, in a
solvent (toluene).  The carbonyl is decomposed (thermally or
photolytically) to deposit an element or alloy consisting of cobalt,
iron, and nickel on the surface of fullerene mo...