Patent Abstract:
A magnetic storage medium is formed of magnetic nanoparticles that are encapsulated within nanotubes (e.g., carbon nanotubes), which are arranged in a substrate to facilitate the reading and writing of information by a read/write head. The substrate may be flexible or rigid. Information is stored on the magnetic nanoparticles via the read/write head of a storage device. These magnetic nanoparticles are arranged into data tracks to store information through encapsulation within the carbon nanotubes. As carbon nanotubes are bendable, the carbon nanotubes may be arranged on flexible or rigid substrates, such as a polymer tape or disk for flexible media, or a glass substrate for rigid disk. A polymer may assist holding the nano-particle filled carbon-tubes to the substrate. Magnetic fields may be applied to draw the carbon nanotubes into data tracks and orient the carbon nanotubes within the data tracks.

Full Description:
BACKGROUND 
     The pursuit of higher performance computing systems is driving the reduction in scale of magnetic storage media. Higher storage densities allow for the reduction of device sizes, an enhancement of device capabilities, and a reduction in data storage costs. To facilitate this increase in magnetic data storage density, industry is constantly searching for structures and processes to reduce the size of information storage sectors and tracks on magnetic tape and magnetic disks. 
     Current magnetic media technology is based upon the ability to magnetize cells of magnetic materials that are deposited directly on a substrate material. These substrate materials are flexible, in the case of magnetic tape of floppy disks, or rigid, in the case of hard disks. The laws of physics place an eventual limit on the ability to increase the storage density of media that is formed of magnetic particles deposited directly on such a storage tape or disk. In the near future, the magnetic storage media industry will reach this storage density limit. It is therefore essential to find new technologies to replace direct deposition of magnetic materials to facilitate further increases in magnetic storage media density. 
     SUMMARY 
     The present is disclosure provides a magnetically enhanced method of curing a data layer of a magnetic storage medium formed of magnetic nanoparticles that are encapsulated within carbon nanotubes, which are arranged on a substrate to facilitate the reading and writing of information by a read/write head. The substrate may be flexible or rigid. 
     Information is stored on the magnetic nanoparticles via the read/write head of a storage device. These magnetic nanoparticles are arranged into data tracks to store information through encapsulation within the carbon nanotubes. As carbon nanotubes are bendable, the carbon nanotubes may be arranged on flexible or rigid substrates, such as a polymer tape or disk for flexible media, or a glass substrate for rigid disk. A data layer is formed on top of the substrate. The data layer includes a polymer matrix that encapsulates the nano-particle filled carbon-tubes. The magnetically enhanced cure is performed to assist in the orientation of carbon nanotubes that encapsulate magnetic nanoparticles with respect to the storage medium. A constant magnetic field is applied to the storage medium before and during the curing of the polymer matrix to assist with the proper orientation of the nanotubes within the data layer. This orientation is then fixed once the polymer matrix is cured. 
     The use of magnetic nanoparticles to store information facilitates a vast increase in the storage density capability of magnetic storage media. Encapsulation of these magnetic nanoparticles within carbon nanotubes allows for the organization of the magnetic nanoparticles into tracks and sectors of information storage media that a read/write head of a storage device can store information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts an isometric view of magnetic nanoparticles encapsulated within a carbon nanotube. 
         FIG. 2  depicts an isometric view of shunt nanoparticles encapsulated within a shunt carbon nanotube. 
         FIG. 3  depicts a cross section of a nano-scale magnetic medium having magnetic and shunt nanoparticles encapsulated within respective carbon nanotubes that are on a substrate. 
         FIG. 4  depicts a view of an arrangement of carbon nanotube data storage tracks on a magnetic tape. 
         FIG. 5  depicts a view of an arrangement of carbon nanotube data storage tracks on a disk. 
         FIG. 6  illustrates the magnetically enhanced cure of magnetic tape to assist in the orientation of carbon nanotubes that encapsulate magnetic nanoparticles. 
         FIG. 7  illustrates the magnetically enhanced cure of a magnetic disk to assist in the orientation of carbon nanotubes that encapsulate magnetic nanoparticles. 
         FIG. 8  illustrates a magnetic tape having carbon nanotubes in various orientations within a data track. 
         FIG. 9  illustrates a magnetic disk having carbon nanotubes in various orientations within an annular data track. 
         FIG. 10  illustrates a magnetic disk having carbon nanotubes in various orientations within a spiral data track. 
         FIG. 11  illustrates a flow chart for manufacturing a magnetic disk having carbon nanotubes. 
         FIG. 12  illustrates a cross-sectional flow diagram for manufacturing a magnetic disk having carbon nanotubes. 
         FIG. 13  illustrates a flow chart for manufacturing a data recording layer. 
         FIG. 14  illustrates formation of a data recording layer. 
         FIG. 15  illustrates a flow chart for manufacturing a magnetic disk having carbon nanotubes. 
         FIG. 16  illustrates a cross-sectional flow diagram for manufacturing a magnetic disk having carbon nanotubes. 
         FIG. 17  illustrates a flow chart for manufacturing a magnetic tape or a flexible magnetic disk having carbon nanotubes. 
         FIG. 18  illustrates a cross-sectional flow diagram for manufacturing a magnetic tape or a flexible magnetic disk having carbon nanotubes. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows magnetic carbon nanotube assembly  100  comprising carbon nanotube  101 . Carbon nanotube  101  is illustrated as a single-wall hollow tube formed of a single layer of carbon atoms in either hexagonal lattice pattern  102  or  112  ( FIG. 2 ). Since carbon nanotube  101  is hollow, it can contain nanoparticles  103  and  104 . Carbon nanoparticle  103  has a high magnetic coercivity so that it can permanently retain a first magnetic field until that field is changed to a second magnetic field. Also, nanoparticle  103  is a particle which does not oxidize or rust on ambient air, such as CrO 2  (chromium dioxide). Such oxidation would cause the loss of the stored magnetic field. Nanoparticle  104  also has a high magnetic coercivity, so that it can permanently retain a first magnetic field until that field is changed to a second magnetic field. Nanoparticle  104  contains high coercivity core  105  which holds the permanent magnetic field. To prevent oxidation, core  105  is encapsulated in shell  106 . An example of core  105  is pure Fe (iron) and shell  106  is iron oxide, such as Fe 2 O 3 , which can be formed for example by chemical vapor deposition (CVD) or atomic layer deposition (ALD). Another example of shell  106  is aluminum oxide, Al 2 O 3 , commonly referred to as alumina, which can be formed for example by chemical vapor deposition (CVD). Another example of shell  106  is a diamond-like film coating. Amorphous (a-C) and hydrogenated amorphous carbon (a-C:H) diamond-like films have high hardness, low friction, electrical insulation, chemical inertness, optical transparency, biological compatibility, ability to absorb photons selectively, smoothness, and resistance to wear. Several methods have been developed for producing diamond-like carbon films: primary ion beam deposition of carbon ions (IBD); sputter deposition of carbon with or without bombardment by an intense flux of ions (physical vapor deposition or PVD); and deposition from an RF plasma, sustained in hydrocarbon gases, onto substrates negatively biased (plasma assisted chemical vapour deposition or PACVD). Silicon and Silicon Oxide, Si and SiO 2 , or any oxide, may also be used for shell  106 , which can be formed for example by chemical vapor deposition (CVD). 
       FIG. 2  shows shunt carbon nanotube assembly  110  comprising carbon nanotube  111 . Like carbon nanotube  101 , carbon nanotube  111  is illustrated as a single-wall hollow tube preferably formed of a single layer of carbon atoms in either hexagonal lattice pattern  112  or  102  ( FIG. 1 ). Hexagonal lattice  112  is rotated ninety degrees from hexagonal lattice  102  and suitable nanotubes comprising either lattice can be used. Since carbon nanotube  111  is. hollow, it can contain nanoparticles  113  and  114 . Carbon nanoparticle  113  has a low or zero magnetic coercivity so that it does not permanently retain a first magnetic field, which allows nanoparticle  113  to act as a magnetic shunt. Also, nanoparticle  113  is a particle which does not oxide or rust in ambient air, such as a soft-ferrite. Nanoparticle  114  also has low or zero coercivity, so that it does not permanently retain a first magnetic field. Nanoparticle  114  contains low or zero coercivity core  115  which provides the desired magnetic shunt. To prevent oxidation, core  115  is encapsulated in shell  116 . An exemplary material for nanoparticle  114  is a soft-ferrite. Soft-ferrites, like other shunt materials, duct magnetic flux without retaining any “after field.” An example of shell  116  is iron oxide, such as Fe 2 O 3 , which can be formed for example by chemical vapor deposition (CVD) or atomic layer deposition (ALD). Another example of shell  116  is aluminum oxide, Al 2 O 3 , commonly referred to as alumina, which can be formed for example by chemical vapor deposition (CVD). Another example of shell  116  is a diamond-like film coating. Amorphous (a-C) and hydrogenated amorphous carbon (a-C:H) diamond-like films have high hardness, low friction, electrical insulation, chemical inertness, optical transparency, biological compatibility, ability to absorb photons selectively, smoothness, and resistance to wear. Several methods have been developed for producing diamond-like carbon films: primary ion beam deposition of carbon ions (IBD); sputter deposition of carbon with or without bombardment by an intense flux of ions (physical vapor deposition or PVD); and deposition from an RF plasma, sustained in hydrocarbon gases, onto substrates negatively biased (plasma assisted chemical vapour deposition or PACVD). Silicon and Silicon Oxide, Si and SiO 2 , may also be used for shell  116 , which can be formed for example by chemical vapor deposition (CVD). 
       FIGS. 1-2  shows Z axis along the length of nanotubes  101  and  111 . Nanotubes  101  and  111  can either be Single-Walled carbon NanoTubes (SWNT) or Multi-Walled carbon NanoTubes (MWNT). MWNT&#39;s may be formed with 2, 3, or more layers. The diameter D of nanotubes  101  and  111  is measured in nanometers. The diameter of the nanotubes, up to 12 nm, limits the size of nanoparticles  103 - 104  and  113 - 114 . In addition to those materials already mentioned, exemplary materials for magnetic nanoparticles  103 - 104  or  113 - 114  include Cobalt (Co), Cobalt (Co) and their alloys, Cobalt-ferrite, Cobalt-nitride, Cobalt-oxide (Co—O), Cobalt-palladium (Co—Pd), Cobalt-platinum (Co—Pt), Iron (Fe), Iron (Fe) and their alloys, Iron-Gold (Fe—Au), Iron-Chromium (Fe—Cr), Iron-nitride (Fe—N), Iron-oxide (Fe 3 O 4 ), Iron-palladium (Fe—Pd), Iron-platinum (Fe—Pt), Fe—Zr—Nb—B, Mn-nitride (Mn—N), Nd—Fe—B, Nd—Fe—B—Nb—Cu, Nickel (Ni), Nickel (Ni) and their alloys, and soft-ferrite. These magnetic nanoparticles can be manufactured with sizes of 10 mm or less, such that these nanoparticles can fit within nanotubes  101  and  111 . Examples of soft-ferrites include Mn—Zn, single crystal Mn—Zn, and Ni—Zn. 
       FIG. 3  shows magnetic storage medium  200 . The T axis is along the thickness direction of magnetic storage medium  200 . If magnetic medium  200  is magnetic tape, then the L axis is along the length of the tape and the W axis is along the width of the tape. Magnetic storage medium  200  comprises substrate  201 , data recording layer  202 , and optional shunt layer  203  in between substrate  210  and data recording layer  202 . For magnetic tape and floppy disks, substrate  201  is typically polytetrafluoroethelyne (PTFE), which is commonly known by the trade name MYLAR™. For hard disks, substrate  201  can be aluminum, glass, or a stiff plastic, such as polycarbonate 
     Data recording layer  202  comprises a plurality magnetic carbon nanotube assemblies  100  which are embedded in a polymer matrix, such as HDPE  230  (High Density Poly Ethylene). Alternately, nanotube assemblies  100  are first encapsulated in HDPE and then embedded in a second polymeric matrix. Nanotubes  100  provide a home for nanoparticles  103 - 104 , so they do not clump into large masses within the data recording layer. Nanotubes  100  may be infused into matrix  230  while matrix  230  is in a liquid form. Matrix  230  may be then coated on to substrate  201  to form data layer  202 . As described in  FIGS. 6-10 , a magnet  601  may be used to orient nanotubes  100  within matrix  230  with respect to substrate  201 . Once nanotubes  100  have been moved into a desired orientation by a magnetic field, matrix  230  may then be cured, thereby making the orientation of nanotubes permanent. 
     Shunt layer  203  comprises a plurality magnetic carbon nanotube assemblies  110  which are embedded in a matrix comprising HDPE  231 . Alternately, nanotube assemblies  110  are first encapsulated in HDPE and then embedded in a second polymeric matrix. Nanotubes  110  provide a home for the shunt nanoparticles  113 - 114 , so they do not clump into large masses within the shunt layer. Use of shunt layer  203  is optional, but it yields improved data recording when included in magnetic storage medium  200 . Nanotubes  110  may be infused into shunt matrix  231  while shunt matrix  231  is in a liquid form. Matrix  231  may be then coated on to substrate  201  to form shunt layer  203 . As described in  FIGS. 6-10 , a magnet  601  may be used to orient nanotubes  110  within shunt matrix  231  with respect to substrate  201 . Once nanotubes  100  have been moved into a desired orientation by a magnetic field, shunt matrix  231  may then be cured, thereby making the orientation of nanotubes permanent. 
     Magnetic recording head  210  comprises write element  212  mounted on a soft ferrite matrix  211 . Write element  212  is essentially a U-shaped piece of low coercivity material and a wire coil, which forms an electro-magnet. That portion of write element  212  adjacent to magnetic storage medium  200  is open, to allow magnetic flux  213  to leave recording head  210  and penetrate magnetic storage medium  200  and imprint data in the form of 1&#39;s and 0&#39;s based on the magnetic polarity of flux  213 . Shunt layer  203  completes the magnetic circuit (analogous to completing an electrical circuit) and keeps flux  213  from “fringing” excessively. Shunt layer  203  permits more crisp edge transitions, thus permitting higher data densities on magnetic storage medium  200 . Thus, data is stored in layer  202  with the assistance of shunt layer  203 . Similarly, shunt layer  203  can assist in the reading of data. Write element  212  may further comprise a Metal-In-Gap (MIG) write head. 
     Data is read from magnetic storage medium  200 , by means of a non-limiting example, via a magnetoresistive head, a spin-valve head which is alternately knows as a giant magnetoresistive “GMR” head, or a tunnel magnetoresistive “TMR” head. 
     The process for forming magnetic storage medium  200  is to first apply shunt layer  203  onto substrate  201 . This may be done as a thin monolayer of nanotubes by running magnetic tape through a solution of HDPE  231  containing nanotubes  110 . This may also be done as a thin monolayer of nanotubes  100  by spin coating a solution of HDPE  231  containing nanotubes  100  onto a magnetic disk. Multiple shunt monolayers can be layered on top of the first monolayer forming shunt layer  203  through repeating this process. To maximize dispersal of nanotubes  100  and  110 , ethylene or another material that disperses carbon nanotubes may be used. 
     Once shunt layer  203  is cured, which may include supplemental heating or compression by rollers, data recording layer  202  is then added. This may be done as a thin monolayer of nanotubes by running magnetic tape through a solution of HDPE  230  containing nanotubes  100 , and then curing the data layer  202 . This may also be done as a thin monolayer of nanotubes  100  by spin coating a solution of HDPE  230  containing nanotubes  100  onto a disk, and then curing the data layer. Multiple data recording monolayers can be layered on top of the first monolayer forming data layer  202  through repeating this process. To maximize dispersal of nanotubes  100  and  110 , ethylene another material that disperses carbon nanotubes may be used. Nanotubes  100  and  110  may be coated with an initial shell of HDPE before being added to HDPE  230  and  231 . 
       FIG. 4  shows magnetic tape media  300  comprising substrate  301 , magnetic data-recording layer  202 , and shunt layer  203 . The L axis is along the length of tape  300 , the W axis is along the width of the tape, and the T axis is along the thickness of the tape. Tape media  300  has substrate  301  typically formed of polytetrafluoroethelyne (PTFE), which is commonly known by the trade name MYLAR™. Shunt layer  203  is formed on substrate  301 . Shunt layer  203  is formed of a monolayer of shunt carbon nanotube assemblies  110 . Assemblies  110  include carbon nanotubes  111  containing nanoparticles  113  and  114 . Carbon nanoparticle  113  has a low or zero magnetic coercivity so that it does not permanently retain a first magnetic field, which allows nanoparticles  103  to act as a magnetic shunt. Data recording layer  202  is formed of a monolayer of carbon nanotube assemblies  100 . Assemblies  100  include carbon nanotubes  101  which contain nanoparticles  103  and  104 . Carbon nanoparticle  103  has a high magnetic coercivity so that it can permanently retain a first magnetic field until that field is changed to a second magnetic field, allowing for data storage. Carbon nanotubes  101  and  111  are oriented such that they are generally parallel to the length wise direction tape media  300 . Data tracks  303  are shown, from magnetic flux transitions recorded by magnetic head  210  in magnetic data-recording layer  202 . 
       FIG. 5  shows magnetic disk  400  with monolayer rings  404  of layer  202  and  203  formed in layers about the center  406  of disk  400 . These layers may be further masked into individual rings  404 . Rings  404  may be formed as distinct rings on disk  400  to form independent tracks. If disk  400  is a hard disk, substrate  402  can be aluminum, glass, or a stiff plastic, such as polycarbonate. If disk  400  is a floppy disk, substrate  402  is typically polytetrafluoroethelyne (PTFE), which is commonly known by the trade name MYLAR™. Z is the direction perpendicular to the disk and the R axis is the radial direction. Shunt layer  203  is formed of a monolayer of shunt carbon nanotube assemblies  110 . Assemblies  110  include carbon nanotubes  111  containing nanoparticles  113  and  114 . Carbon nanoparticle  113  has a low or zero magnetic coercivity so that it does not permanently retain a first magnetic field, which allows nanoparticle  113  to act as a magnetic shunt. Data recording layer  202  is formed of a monolayer of carbon nanotube assemblies  100 . Assemblies  100  include carbon nanotubes  101  which contain nanoparticles  103  and  104 . Carbon nanoparticle  103  has a high magnetic coercivity so that it can permanently retain a first magnetic field until that field is changed that field is changed to a second magnetic field, allowing for data storage. Carbon nanotubes  101  and  111  may be oriented such that they extend radially from the center of disk  400 . Alternatively, carbon nanotubes  101  and  111  may be oriented such that they extend in a spiral pattern from the center of the disk  400 . 
     One method of forming rings  404  is through a photo-etching process. Layers  202  and  203  are first deposited onto disk  400  preferably through a spin coating process. A layer of photoresist material is then deposited on top of layers  202  and  203 . This layer of photoresist is exposed through a mask, thereby patterning layers  202  and  203 . A removal process leaves the patterned layers  202  and  203 . While shown as rings  404 , layers  202  and  203  may be patterned into any desirable track or sector pattern for data storage. Alternatively, when disk  400  is made of polycarbonate, rings  404  could be formed through a molding process. A top surface of data recording layer  202  may further comprise buckyballs  299 , which would act to reduce friction between the recording layer  202  and the magnetic head  210 . 
       FIG. 6  illustrates the magnetically enhanced cure of magnetic tape to assist in the orientation of carbon nanotubes that encapsulate magnetic nanoparticles.  FIG. 7  illustrates the magnetically enhanced cure of a magnetic disk to assist in the orientation of carbon nanotubes that encapsulate magnetic nanoparticles. By use of magnet  601 , a constant magnetic field is applied to the magnetic tape  300  and disk  400  to assist with the proper orientation of the nanotube assemblies  100  while tape  300  and disk  400  is cured (polymer matrix  230  containing nanotube assemblies  100  and  110  adheres to the substrate  201  and  301 ). Nanotube assemblies  100  are free to move within polymer matrix  230  prior to the curing of polymer matrix  230  as polymer matrix  230  is in a liquid, gel, or powdered state when initially applied to substrate  301  or  402 . Matrix  231  may also be applied in a liquid, gel, or powdered state. When nanotube assemblies  100  are free to move within polymer matrix  230 , magnet  601  is able to assist in the orientation of nanotube assemblies  100  with respect to magnetic tape  300  or disk  400  by applying a magnetic field that acts upon nanotube assemblies  100 . Note that within a preferred embodiment, nanotube assemblies  100  are only present within data tracks  303  and  404 . In this preferred embodiment, the space between data tracks  303  and  404  is preferably void of any nanotube assemblies  100 . Magnet  601  is merely drawn in  FIGS. 6 and 7  as being exemplary of the application of magnetism relative to magnetic tape  300  or disk  400 . Specific magnet configurations that can create suitable field lines to properly orient carbon nanotubes  101  as shown in  FIGS. 8 ,  9  and  10  are well known and exist in many varieties, and for example are disclosed in the publication authored by Oleg D. Jefimenko,  Electricity and Magnetism: An Introduction to the Theory of Electric and Magnetic Fields , second edition, (ISBN 0-917406-08-7), which is hereby incorporated by reference. Nanotube assemblies  100  preferably contain more than one nanoparticle  103 / 104  so that magnet  601  can magnetically align nanotubes  101 . 
     By applying the magnetic field, magnet  601  is able to orient nanotube assemblies  100  into a generally uniform orientation with respect to substrates  301  or  402 . For example, magnet  601  may be manipulated with respect to magnetic tape  300  to orient nanotube assemblies  100  parallel to the lengthwise axis of each data track. Alternatively, magnet  601  may be manipulated with respect to magnetic tape  300  to orient nanotube assemblies  100  perpendicular to the lengthwise axis of each data track. Magnet  601  may be manipulated with respect to disk  400  to orient nanotube assemblies  100  radially with respect to the center of disk  400 . Alternatively, magnet  601  may be manipulated with respect to disk  400  to orient nanotube assemblies  100  parallel to the direction of data rings  404  such that each nanotube is generally perpendicular the radial axis of disk  400 . Please note that these orientations shown in this Figure are merely exemplary and any alignment of nanotubes is conceived. Magnet  601 , which may be either a permanent magnet or an electromagnet, exerts a constant magnetic field on tape  300  and disk  400  as the polymer matrix cures. If magnet  601  is a permanent magnet, it may be made out of magnetized soft iron. If magnet  601  is an electromagnet, then a electrical coil (not shown) is wound around the ferrite body of magnet  601  and when a DC current flows through this electrical coil, a magnetic field is created. 
       FIG. 8  illustrates a magnetic tape  300  having carbon nanotubes  101  in various orientations within a data track  303 . Magnet  601  can align carbon nanotubes  101  to an orientation  305  in which the longitudinal axis of carbon nanotubes  101  is parallel to the lengthwise axis of data track  303 . Alternatively, magnet  601  can align carbon nanotubes  101  to an orientation  306  in which the longitudinal axis of carbon nanotubes  101  is rotated 45 degrees with respect to the lengthwise axis of data track  303 . In addition, magnet  601  can align carbon nanotubes  101  to an orientation  307  in which the longitudinal axis of carbon nanotubes  101  is perpendicular to the lengthwise axis of data track  303 . The areas  304  between each data track  303  may, in a preferred embodiment, be void of any carbon nanotubes  101 . In a preferred embodiment, shunt layer  203  is not present in areas  304 . A pair of parallel plates in a configuration like a capacitor could generate a magnetic field between the plates having linear magnetic field lines that could create a magnetic field that would orient nanotubes  101  in the manner shown in orientations  305 ,  306 , or  307 . For example, having data tracks  303  run parallel to the magnetic field lines would create the orientation  305 . Rotating data tracks  303  by 45 degrees with respect to the magnetic field lines would create the orientation  306 . Positioning the data tracks  303  to run perpendicular to the magnetic field lines would create the orientation  307 . Please note that these magnet  601  and magnetic tape  300  orientations are based upon the carbon nanotubes orienting themselves parallel to the magnetic field lines. Also, please note that these orientations shown in this Figure are merely exemplary and any alignment of nanotubes is conceived. 
       FIG. 9  illustrates a magnetic disk  400  having carbon nanotubes  101  in various orientations within an annular data track  404 . Magnet  601  can align carbon nanotubes  101  to an orientation  410  in which the longitudinal axis of carbon nanotubes  101  is parallel to a tangent of annular data track  404 . For example, an isolated uniformly charged sphere or rod placed at the center  406  of disk  400  would create magnetic field lines that would orient nanotubes  101  in the manner shown in orientation  410 . Alternatively, magnet  601  can align carbon nanotubes  101  to an orientation  412  in which the longitudinal axis of carbon nanotubes  101  is rotated  45  degrees with respect to a radial axis of disk  400 . In addition, magnet  601  can align carbon nanotubes  101  to an orientation  408  in which the longitudinal axis of carbon nanotubes  101  is aligned to a radial axis of disk  400 . For example, a uniformly charged rod extending through center  406  with a uniformly charged cylinder surrounding disk  400  could create a magnetic field that would orient nantubes  101  in the manner shown in orientation  408 . Alternatively, placing a uniformly charged sphere at the center  406  and surrounding disk  400  with another uniformly charged sphere could create magnetic field lines that would orient nanotubes  101  in the manner shown in orientation  408 . The areas  407  between each data track  404  may, in a preferred embodiment, be void of any carbon nanotubes  101 . In a preferred embodiment, layer  202  is present only in data tracks  404 . However, carbon nanotubes  111  may still be present within areas  407 . In a preferred embodiment, shunt layer  203  is not present in areas  407 . Alternatively, shunt layer  203  may extend partially into areas  407  on either side of data track  404  to prevent fringing at the boundaries of data track  404 . Please note that these orientations shown in this Figure are merely exemplary and any alignment of nanotubes is conceived. 
       FIG. 10  illustrates a magnetic disk  400  having carbon nanotubes  101  in various orientations within a spiral data track  414 . Magnet  601  can align carbon nanotubes  101  to an orientation  420  in which the longitudinal axis of carbon nanotubes  101  is parallel to a tangent of spiral data track  414 . Alternatively, magnet  601  can align carbon nanotubes  101  to an orientation  418  in which the longitudinal axis of carbon nanotubes  101  is rotated 45 degrees with respect to a tangent of spiral data track  414 . In addition, magnet  601  can align carbon nanotubes  101  to an orientation  422  in which the longitudinal axis of carbon nanotubes  101  is perpendicular to a tangent of spiral data track  414 . The areas  416  between each data track  414  may, in a preferred embodiment, be void of any carbon nanotubes  101 . In a preferred embodiment, layer  202  is present only in data tracks  414 . Preferably, shunt layer  203  is not be present in areas  416  or shunt layer  203  may extend partially into areas  416  on either side of data track  414  to prevent fringing at the boundaries of data track  414 . 
       FIG. 11  illustrates a flow chart for manufacturing a magnetic disk  400  having carbon nanotubes  101  and  111 . This flow chart begins at START, step  1000 . Substrate  402  for magnetic disk  400  is, in one embodiment, a rigid substrate made for example of glass, aluminum, or an aluminum oxide. Substrate  402  is manufactured to have tracks  404  formed in substrate  402  in step  1002 . Tracks  404  may be formed, for example, by a stamping process with a glass substrate. Alternatively, for example, tracks  404  may be formed through a photolithography process. Note that for  FIGS. 11-16 , tracks  414  may be substituted for tracks  404 . Once tracks  404  are formed, shunt matrix  231  containing shunt nanotube assemblies  110  are deposited intro tracks  404  to form layer  203  in step  1004 . Shunt matrix  231  may be in liquid, gel, or powdered form. During the deposition of shunt matrix  231  containing shunt nanotube assemblies  110 , substrate  404  may be vibrated to aid shunt matrix  231  with filling tracks  404 . Substrate  404  may be vibrated with subsonic, sonic, or ultra-sonic vibrations. While being deposited, shunt matrix  231  is preferably in a liquid state, or may be in a gel, or powdered state. Once shunt matrix  231  is deposited within tracks  404 , shunt matrix  231  is cured into a solid state. In step  1006 , data recording matrix  230  containing nanotube assemblies  100  is deposited into tracks  404  to form layer  203 . Substrate  402  is vibrated with subsonic, sonic, or ultra-sonic vibrations to assist data recording matrix with filling tracks  404 . Data recording matrix  230  is preferably in a liquid state 
       FIG. 12  illustrates a cross-sectional flow diagram for manufacturing a magnetic disk  400  having carbon nanotubes  101  and  111  in accordance with the process described in  FIG. 11 . In view A, tracks  404  are formed in substrate  402  as described above in step  1002 . Note that tracks  404  form a channel. In view B, shunt layer  203  is deposited within tracks  404  as described above in step  1004 . In view C, data recording layer  202  is deposited within tracks  404  as described above in steps  1006  and  1008 . 
       FIG. 13  illustrates a flow chart for manufacturing a data recording layer  202 . The manufacturing process begins with step  2000  when liquid data recording layer matrix  230  has been deposited on substrate  402  and within data tracks  404 . Data recording matrix  230  may also be applied in powdered or gel form. In step  2002 , a magnet  602 , shown in  FIG. 14 , creates a magnetic field  428  through track  404  that acts upon nanotube assemblies  100 . Magnetic field  428  draws carbon nanotubes  100  along paths  426  from the upper portion  422  of data recording layer matrix  230  down into the lower portion  424  of data recording matrix  230  within track  404 , thereby creating an increased concentration of nanotubes  100  within track  404 . In step  2004 , substrate  402  is then vibrated to aid the data recording layer matrix  230  with filling track  404 . In addition, vibrating substrate  402  aids magnet  601  with orienting nanotubes  100  with respect to track  404 . Once nanotubes  100  are in the proper orientation, data recording matrix  230  is cured into a solid state, step  2006 , thereby forming layer  202 . In step  2010 , data recording layer  202  may be planarized to be flush with the sidewalls formed in substrate  402  that extend on either 
       FIG. 14  illustrates an exemplary formation of a data recording layer  202  in accordance with the process described in  FIG. 13 . Magnet  602 , is shown in this exemplary embodiment, to be positioned underneath data track  404 . The magnetic field  428  generated by magnet  602  pulls nanotubes  100  down into track  404 . Consequently, upper portions  422  of data recording matrix  230  have lower concentrations of nanotubes  100  than lower portion  424  of data recording matrix  230  within track  404  over shunt layer  203 . Thus, this process increases the density of carbon nanotubes  100  within track  404  than otherwise existed in data recording matrix  230  when it was deposited. 
       FIG. 15  illustrates a flow chart for manufacturing a magnetic disk  400  having carbon nanotubes  101  and  111 . The process begins in step  3000 . A shunt barrier layer  430  is deposited over substrate  402  in step  3002 . Shunt barrier layer  430  may be comprised of a shunt matrix  231  material that does not include nanotube assemblies  110 . Alternatively, shunt barrier layer  430  may be formed of an oxide, silicon, glass, or other material. Shunt barrier layer  430  is then patterned to form tracks  404  through a photolithographic process, a stamping process, or other process capable of forming channels  404 . In step  3004 , shunt matrix  231  containing shunt nanotubes  110  is deposited into tracks  404  to form layer  203 . Substrate  402  is then vibrated to assist the liquid shunt matrix  231  with filling tracks  404 . Shunt matrix  231  is then cured into a solid state to form layer  203 . In step  3006 , data recording matrix  230  containing nanotubes  100  is deposited into tracks  404  to form layer  202 . Substrate  402  is sonically or sub-sonically vibrated to assist the liquid data recording matrix  230  with filling tracks  404 . In addition, substrate  402  is then vibrated to assist magnet  601  with orienting nanotubes  100  within tracks  404 . Once nanotubes  100  are oriented into a desired position, data recording matrix  230  is cured into a solid state thereby forming layer  202 . In step  3008 , data recording layer  202  may be planarized to be flush with the sidewalls formed in substrate  402  that extend on either side of channel  404 . Disk  400  may then be optionally compressed. This process then terminates in step  3010 . 
       FIG. 16  illustrates a cross-sectional flow diagram for manufacturing a magnetic disk  400  having carbon nanotubes  101  and  111  in accordance with the process described in  FIG. 15 . In view A, tracks  404  are formed in substrate  402 . In view B, shunt layer  203  is deposited within tracks  404 . In view C, data recording layer  202  is deposited within tracks  404 . 
       FIG. 17  illustrates a flow chart for manufacturing a magnetic tape  300  or a flexible magnetic disk  400  having carbon nanotubes  101  and  111 . The process beings with step  4000 . In step  4002 , shunt matrix  231  containing shunt nanotubes  110  is printed onto substrate  301  or  402  to form tracks  303  or  404 . Shunt matrix containing shunt nanotubes  110  maybe in a liquid state that is then cured into a solid state to form shunt layer  203 , or a powder form that is then baked into a solid state to form shunt layer  203 . In step  4004 , data recording matrix  230  containing nanotubes  100  is printed on top of shunt layer  203  in tracks  303  or  404 . Data recording matrix containing nanotubes  100  maybe in a liquid state that is then cured into a solid state to form data recording layer  202 , or a powder form that is then baked into a solid state to form data recording layer  202 . The process then ends in step  4006 . 
       FIG. 18  illustrates a cross-sectional flow diagram for manufacturing a magnetic tape  300  or a flexible magnetic disk  400  having carbon nanotubes  100  or  101  in accordance with the process described in  FIG. 17 . In view A, tracks  303  or  404  are formed by printing layer  203  on substrate  301  or  402 . In view B, tracks  303  or  404  are further formed by printing layer  202  on top of layer  203 . Note that while shown printed on a substrate  301  or  402 , ink containing carbon nanotubes  100  having magnetic particles may be printed on any other printable surface and used for applications that include, for example, RFID applications, bar codes, or other printed identifiers. In addition, carbon nanotubes containing magnetic nanoparticles may be infused in a pattern in paper currency to reduce the possibility of counterfeiting. 
     While the technology has been shown and described with reference to a particular embodiment thereof, it will be understood to those skilled in the art, that various changes in form and details may be made therein without departing from the spirit and scope of the invention disclosure.

Technology Classification (CPC): 6