U.S. patent application number 11/739597 was filed with the patent office on 2008-01-24 for thin film magnetic recording media.
This patent application is currently assigned to Agency for Science, Technology and Research, a Singapore corporation. Invention is credited to Jingsheng Chen, Jian-Ping Wang.
Application Number | 20080020241 11/739597 |
Document ID | / |
Family ID | 33129405 |
Filed Date | 2008-01-24 |
United States Patent
Application |
20080020241 |
Kind Code |
A1 |
Chen; Jingsheng ; et
al. |
January 24, 2008 |
THIN FILM MAGNETIC RECORDING MEDIA
Abstract
A method and apparatus for forming a thin film magnetic
recording media, the method comprises generating magnetic
nanoclusters from a target of magnetic material, crystallizing the
magnetic nanoclusters, and depositing the magnetic nanoclusters
onto a substrate to form a thin film of magnetic particles thereon.
The magnetic nanoclusters are deposited onto the substrate after
crystallized and therefore after the deposition. The apparatus
comprises a first chamber, a second chamber connected to the first
chamber, and a third chamber connected to the second chamber. The
first chamber has a source for generating magnetic nanoclusters.
The second chamber is to receive the magnetic nanoclusters and
crystallize the magnetic nanoclusters. The third chamber is to
receive the crystallized magnetic nanoclusters from the second
chamber and deposit the crystallized magnetic nanoclusters onto the
substrate positioned therein.
Inventors: |
Chen; Jingsheng; (Singapore,
SG) ; Wang; Jian-Ping; (Minneapolis, MN) |
Correspondence
Address: |
FISH & RICHARDSON PC
P.O. BOX 1022
MINNEAPOLIS
MN
55440-1022
US
|
Assignee: |
Agency for Science, Technology and
Research, a Singapore corporation
|
Family ID: |
33129405 |
Appl. No.: |
11/739597 |
Filed: |
April 24, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10777018 |
Feb 11, 2004 |
7208204 |
|
|
11739597 |
Apr 24, 2007 |
|
|
|
Current U.S.
Class: |
428/826 ;
118/600; 427/128; G9B/5.276; G9B/5.295 |
Current CPC
Class: |
C23C 14/06 20130101;
C23C 14/34 20130101; G11B 5/712 20130101; G11B 5/714 20130101; C23C
14/228 20130101; G11B 5/84 20130101 |
Class at
Publication: |
428/826 ;
118/600; 427/128 |
International
Class: |
G11B 5/64 20060101
G11B005/64; B05C 11/00 20060101 B05C011/00; B05D 5/12 20060101
B05D005/12 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 11, 2003 |
SG |
200300519-6 |
Claims
1-17. (canceled)
18. An apparatus for forming a thin film magnetic recording medium
onto a substrate, the apparatus comprising: a first chamber having
a source for generating magnetic nanoclusters; a second chamber
connected to the first chamber for receiving and crystallizing the
magnetic nanoclusters, a third chamber connected to the second
chamber for receiving the crystallized magnetic nanoclusters and
depositing the crystallized magnetic nanoclusters onto the
substrate positioned therein, wherein the magnetic nanoclusters are
deposited on the substrate after crystallized.
19. The apparatus as recited in claim 18, further comprising a
first supplier for providing a first non-magnetic material to
encapsulate the magnetic nanoclusters.
20. The apparatus as recited in claim 19, wherein the first
non-magnetic material comprises a surfactant.
21. The apparatus as recited in claim 20, wherein the surfactant
comprises at least one of a group consisting of fatty acids, alkyl
thiols, alkyl diulfides, alkyl nitrites and alkyl isonitiles.
22. The apparatus as recited in claim 18, further comprising a
rotatable stage for holding the substrate in the third chamber.
23. The apparatus as recited in claim 18, further comprising a
second supplier for depositing a second non-magnetic material onto
the substrate upon deposition of the magnetic nanocrystals.
24. The apparatus as recited in claim 23, wherein the second
non-magnetic material comprises at least one of a group consisting
of C, SiO.sub.2, Si.sub.3N.sub.4, BN and carbon hydrogenate
polymer.
25. The apparatus as recited in claim 48, wherein the magnetic
material comprises at least one of a group consisting of Co, Fe,
Ni, Sm, Pt, Cr, Ta, Nd, Pd, Gd, B, N, C, P, Ti, W, Mo, Ag, Ru, Au,
Nb, Pb, Dy.
26. The apparatus as recited in claim 25, further comprising at
least one of a group consisting of a binary alloy and a ternary
alloy of the magnetic material.
27. A thin film magnetic recording medium comprising: a substrate;
a magnetic thin film layer disposed on the substrate, wherein the
magnetic thin film layer has magnetic particles isolated by a
non-magnetic content, wherein the magnetic particles are formed on
the substrate after crystallization.
28. The thin film magnetic recording medium as recited in claim 27,
wherein each of the magnetic particles has a magnetic easy axis
that is anisotropically orientated.
29. The thin film magnetic recording medium as recited in claim 27,
wherein the magnetic particles having a dimension of less than
about 8 nm.
30. The thin film magnetic recording medium as recited in claim 29,
wherein the magnetic particles having a distribution width of less
than about 10%.
31. The thin film magnetic recording medium as recited in claim 27,
wherein the non-magnetic content comprises at least one of a group
consisting of fatty acids, alkyl thiols, alkyl diulfides, alkyl
nitrites and alkyl isonitiles.
32. The thin film magnetic recording medium as recited in claim 27,
wherein the non-magnetic content comprises at least one of C,
SiO.sub.2, Si.sub.3N.sub.4, BN and carbon hydrogenate polymer.
33. The thin film magnetic recording medium as recited in claim 27,
further comprising a protective overcoating disposed on the
magnetic thin film layer.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to magnetic recording media.
In particular, it relates to thin film magnetic recording media for
data storage devices.
BACKGROUND OF THE INVENTION
[0002] The rapid development of computer and information technology
has resulted in great demand for high capacity storage devices.
Currently, these storage devices are being pushed to their limits
by applications as diverse as digital video editing and genomics.
Therefore, the data storage industry is continually under pressure
to increase the capacity of data storage devices. One of the
primary methods to increase capacity is to increase the recording
density of the magnetic recording media in most storage devices. To
achieve an ultra-high recording density of, for example, about 100
Gbits/inch.sup.2 or higher, magnetic recording media are required
to possess a low remnant-thickness product (Mr.delta.), a high
coercivity (Hc) as well as a high signal-to-media noise (S/Nm).
[0003] In a conventional magnetic recording media, such as a Cobalt
(Co) based alloy, non-magnetic elements such as Chromium (Cr)
and/or Boron (B) are incorporated into the thin film magnetic
recording media to reduce the grain size as well as to reduce the
intergranular coupling effect of the magnetic particles in the
recording media. The result is a magnetic recording medium having a
grain size of about 8-12 nanometers (nm) with a distribution width
of about 20% or more. In this context, the term "distribution
width" denotes the Full Width at Half Maximum (FWHM) height of the
grain size distribution.
[0004] In order to obtain a high S/N.sub.m magnetic recording
media, the grain size and their distribution width as well as the
intergranular coupling between the magnetic grains must be properly
controlled to further scale down.
[0005] Reduction of grain size for Co-based alloy recording media
is limited by the thermal-instability of the magnetic grains or
particles, commonly referred to as the "superparamagnetism" effect.
Attempts to overcome this limitation are illustrated in "Effect Of
Magnetic Anisotropy Distribution In Longitudinal Thin Film Media"
by Hee et al (J. Appl. Phys., Volume 87, 5535-5537, 2000) and U.S.
Pat. No. 6,183,606 to Kuo et al. The Hee article discloses a method
using highly oriented media to allow further reduction of the grain
size. In contrast, the Kuo patent uses L1.sub.0 ordered FePt or
CoPt material to form longitudinal or perpendicular magnetic
recording media with very small magnetically stable grains.
[0006] While the above methods provide possibilities to obtain
magnetically stabled grains with further reduced size in a first
place, in the subsequent post-deposition annealing process, a high
temperature, for example 600.degree. C. or above, is to apply to
the substrate in order to obtain recording media with an
appropriate crystallized structure or with chemically ordered
L1.sub.0 FePt or CoPt. Unfortunately, this high temperature
annealing process also increases grain size from about 10
nanometers (nm) to about 30 nm in the deposited thin film, which
eventually reduces the recording density. In addition, no solution
is provided by these methods to control the grain distribution
width. Due to the larger grain size and their wide distribution
width, these films have presented rather poor recording properties,
in particular a very low S/N.sub.m. Moreover, the high-temperature
annealing process is not compatible with existing magnetic
recording media fabrication process and materials.
SUMMARY OF THE INVENTION
[0007] The present invention seeks to provide a method and
apparatus for forming thin film magnetic recording media with
higher recording density by virtue of the reduced grain size and
distribution width. The present invention also provides a thin film
magnetic recording medium formed accordingly. The present invention
successfully eliminates the post annealing process necessary for
the conventional methods as the deposition is done after the
magnetic particles are crystallized, therefore avoids the grain
growth after the formation of the thin film magnetic recording
media by heating up the substrate for annealing purpose. According
to the present invention, the magnetic easy axis of the magnetic
particles are finely controlled during the deposition process and
further, the magnetic particles are well isolated from each other
either before or during the deposition process.
[0008] In accordance with a first aspect of the present invention,
there is provided a method for forming a thin film magnetic
recording media, the method comprises generating magnetic
nanoclusters from a target of magnetic material, crystallizing the
magnetic nanoclusters, and depositing the magnetic nanoclusters
onto a substrate to form a thin film of magnetic particles thereon.
The magnetic nanoclusters are deposited onto the substrate after
crystallized and therefore after the deposition, it is unnecessary
to heat up the substrate.
[0009] In accordance with a second aspect of the present invention,
there is provided an apparatus for forming a thin film magnetic
recording media onto a substrate. The apparatus comprises a first
chamber, a second chamber connected to the first chamber, and a
third chamber connected to the second chamber. The first chamber
has a source for generating magnetic nanoclusters. The second
chamber is to receive the magnetic nanoclusters and crystallize the
magnetic nanoclusters. The third chamber is to receive the
crystallized magnetic nanoclusters from the second chamber and
deposit the crystallized magnetic nanoclusters onto the substrate
positioned therein.
[0010] In accordance with a third aspect of the present invention,
there is provided a thin film magnetic recording medium, the medium
comprises a non-magnetic substrate and a magnetic thin film layer
disposed on the substrate. The magnetic thin film layer comprises
magnetic particles isolated by a non-magnetic material, and the
magnetic particles are formed on the substrate after
crystallized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1A is an enlarged cross sectional view showing a thin
film magnetic recording medium according to one embodiment of the
present invention.
[0012] FIG. 1B is an enlarged cross sectional view showing a thin
film magnetic recording medium according to another embodiment of
the present invention.
[0013] FIG. 2A is an enlarged top view showing a parallel
magnetization orientation of the magnetic nanoparticles formed
according to one embodiment of the present invention.
[0014] FIG. 2B is an enlarged top view showing a circumferential
magnetization orientation of the magnetic nanoparticles formed
according to another embodiment of the present invention.
[0015] FIGS. 3A and 3B are enlarged cross sectional views showing
perpendicular magnetization orientations of the magnetic
nanoparticles formed according to the present invention.
[0016] FIG. 4 is a schematic diagram showing an apparatus for
forming magnetic thin film onto a substrate according to one
embodiment of the present invention.
[0017] FIGS. 5A, 5B and 5C are schematic diagrams showing various
configurations of the magnetic field according to the present
invention.
[0018] FIG. 6 is a schematic diagram showing an apparatus for
forming magnetic thin film onto a substrate according to another
embodiment of the present invention.
[0019] FIG. 7 is a schematic diagram showing an apparatus for
forming magnetic thin film onto a substrate according to a further
embodiment of the present invention.
[0020] FIG. 8 is a flow chart showing a method for forming magnetic
thin film onto a substrate according to one embodiment of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] FIG. 1A illustrates a thin film magnetic recording medium
formed according to one embodiment of the present invention. The
thin film magnetic recording medium 100 comprises a substrate 110,
a thin film magnetic layer 120 deposited onto the substrate 110 and
a protective overcoating 130 deposited on the thin film magnetic
layer 120. The substrate 110 may be formed of a non-magnetic
material such as silicon, glass, or aluminum alloy. The thin film
magnetic layer 120 comprises a plurality of magnetic particles 122.
Examples of magnetic materials that may be used to form magnetic
particles 122 include Co, Fe, Ni, Sm, Pt, Cr, Ta, Nd, Pd, Gd, B, N,
C, P, Ti, W, Mo, Ag, Ru, Au, Nb, Pb, Dy, a binary alloy of
aforesaid elements, a ternary alloy of said elements, an oxide of
Fe further comprising at least one of the said elements other than
Fe, barium ferrite and strontium ferrite, carbide and nitride of
the said elements. The preferred magnetic materials are, for
example, CoPt, FePt or CoPd.
[0022] The magnetic particles 122 are encapsulated by non-magnetic
material 124a. The magnetic particles 122 are oriented with its
magnetic easy axis 126 aligned parallel to a surface 114 of the
substrate 110. In FIG. 1B, the magnetic particles 122 are disposed
on the substrate 110 simultaneously with a non-magnetic material
124b, such that the magnetic particles 122 are dispersed within the
non-magnetic material 124b. It should be appreciated that the
intergranular coupling effect of the magnetic particles isolated by
the non-magnetic material 124a (FIG. 1) and 124b (FIG. 2) in the
above structure can be effectively reduced.
[0023] FIGS. 2A and 2B show two examples of the highly oriented
alignment of magnetic easy axis of the magnetic particles in the
magnetic thin film for longitudinal recording media. FIG. 2A shows
that the magnetic easy axes 226a of the magnetic particles 222 are
parallel to the surface of the substrate 210. FIG. 2B shows that
the magnetic easy axes 226a of the magnetic particles 222 are
parallel to the surface of the substrate 210 and are
circumferentially aligned.
[0024] FIG. 3A illustrates a thin film magnetic recording medium
formed according to another embodiment of the present invention.
The thin film magnetic recording medium 300 comprises a substrate
310, a thin film magnetic layer 320 deposited onto the substrate
110 and a protective overcoating 330 deposited on the thin film
magnetic layer 120. The substrate 110 may be formed of a
non-magnetic material made of, for example, a silicon wafer, glass
or aluminum alloy. The thin film magnetic layer 320 includes a
plurality of magnetic particles 322 comprising magnetic materials,
such as Co, Fe, Ni, Sm, Pt, Cr, Ta, Nd, Pd, Gd, B, N, C, P, Ti, W,
Mo, Ag, Ru, Au, Nb, Pb, Dy, a binary alloy of aforesaid elements, a
ternary alloy of said elements, an oxide of Fe further comprising
at least one of the said elements other than Fe, barium ferrite and
strontium ferrite, carbide and nitride of the said elements.
[0025] The magnetic particles 322 are encapsulated by a layer of
non-magnetic material 324a according to the method illustrated
below, and with its magnetic easy axis 326 aligned perpendicular to
the surface 314 of the substrate 310. In FIG. 3B, the magnetic
particles 322 are disposed on the substrate 310 simultaneously with
a non-magnetic material 324b, such that the magnetic particles 322
are dispersed within the non-magnetic material 324b.
[0026] As shown in FIG. 4, an apparatus for forming magnetic thin
film onto a substrate according to one embodiment of the present
invention comprises a cluster-forming chamber 410, a heating
chamber 420, an encapsulation chamber 429 and a deposition chamber
430. The cluster-forming chamber 410 comprises a target 416 made of
a magnetic material selected from, for example, Co, Fe, Ni, Sm, Pt,
Cr, Ta, Nd, Pd, Gd, B, N, C, P, Ti, W, Mo, Ag, Ru, Au, Nb, Pb, Dy,
a binary alloy of aforesaid elements, a ternary alloy of said
elements, an oxide of Fe further comprising at least one of the
said elements other than Fe, barium ferrite and strontium ferrite,
carbide and nitride of the said elements. The cluster-forming
chamber 410 comprises a power unit 412 connected to an anode 413
and the target 416 (which is used as a cathode). The
cluster-forming chamber 410 also includes a first conduit 411 for
supplying a first gas, such as argon (Ar) and a second conduit 415
for supplying a second gas such as helium (He). The Ar serves as
both sputtering gas and aggregation gas while the He is used to
control the cluster size and initial distribution width due to its
high heat-transfer ability. A liquid nitrogen cooling unit 414 is
also provided for promoting the formation of the cluster with
desired size. Examples of the power unit 412 are a direct current
(DC) or radio frequency (RF) power supply. The cluster-forming
chamber 410 preferably operates at a working pressure in a range of
about 0.1 Torr to 1 Torr, which is higher than that of the
conventional sputtering pressure. The purpose of using a pressure
for sputtering in this level is to provide more collision chance of
the particle and to form large particle. The parameters of
controlling the particle size include gas pressure, gas flow rate,
ratio of Ar and He. A diaphragm 417 is provided at one end of the
nitrogen cooling unit. Another diaphragm 418 is provided to connect
the cluster-forming chamber 410 and the heating chamber 420.
[0027] Pumping systems 433, 434, and 435 are provided for adjusting
the pressure of the cluster-forming chamber 410, the encapsulation
chamber 429 and the deposition chamber 430. The pressure of the
deposition chamber 430 is maintained at a level lower than the
pressure of the other two chambers to enable cluster transportation
from the cluster-forming chamber 410 to the deposition chamber 430.
The pressure range of the cluster-forming chamber 410, the
encapsulation chamber 429 and the deposition chamber 430 can be set
to about 0.1-1 Torr, 10.sup.-4 Torr, and 10.sup.-6 Torr,
respectively.
[0028] At the start of the process, energized argon gas ions (Ar+)
are accelerated towards the target 416 to eject atoms 421 from the
target 16 upon impact. The ejected atoms 421 are then decelerated
by collision with the argon gas (Ar+) and start to agglomerate to
form clusters. The liquid nitrogen cooling unit 414 and helium
supplied from the conduit 415 aid in cooling the ejected atoms 421
to form a set of clusters 422.
[0029] After being exposed to the noble gases (Ar+), the clusters
422 then move through the diaphragm 417 and agglomerate together to
form a set of larger clusters 423, which continue move onwards to
the heating chamber 420 through diaphragm 418, and further form
final clusters 424 in the heating chamber 420. The clusters 424 may
consist of several hundred magnetic atoms up to several million
magnetic atoms, which are loosely bonded with each other. In the
process, atoms are agglomerated together to form clusters, and more
atoms are attached to the boundary portions of the clusters
continuously. As a result, the clusters will be formed with larger
sized agglomerates located at the center portion and with
relatively smaller sized agglomerates locates at the boundary
portion. Upon passing through the diaphragm 418, smaller sized
agglomerates located at the boundary portions of the clusters 423
can be trimmed off by the diaphragm. As a result, the clusters 424
passing through the diaphragm will have the smaller sized
agglomerates removed. Therefore, clusters with a distribution width
smaller than that of the clusters 423 before the diaphragm 418 can
be obtained. In this embodiment, the dimension of the clusters 424
is in a range of about 1 nm to 20 nm and a distribution width of
about 10% or less.
[0030] It should be appreciated according to the above illustration
that various parameters may be adjusted to control the dimension
and distribution width, including the pressure of the
cluster-forming chamber 410, the sputtering rate of the target
materials, the ratio of the helium to other noble gases, the
distance between the target 416 and the diaphragm 417 and the size
of the diaphragms 417 and 418, etc.
[0031] The apparatus further comprises a number of heaters 419 for
heating the gas-phase clusters 424 to a temperature of about
900.degree. C. to achieve crystallization. Examples of the heaters
419 include a resistance furnace heater or a lamp heater. After
heating, the clusters 424 are converted into crystallized magnetic
nanoclusters 425 with a desired crystalline structure for data
storage purpose.
[0032] The magnetic nanoclusters 425 are then moved to the
encapsulation chamber 429. A surfactant 427 is then supplied to the
encapsulation chamber by a spray nozzle 428, such as a nebuliser.
The surfactant is preferably a material which can be absorbed by
the magnetic nanocrystals 425 to form encapsulated magnetic
nanocrystals 426. The surfactant 427 may be selected from a group
of organic materials, including fatty acids, alkyl thiols, alkyl
diulfides, alkyl nitrites and alkyl isonitiles, which is an end
group that is attracted to the magnetic nanocrystals 425. The
surfactant may also be a methylene having a chain 8 to 12 units
long, which provides steric repulsion to prevent the magnetic
nanocrystals 425 from adhering to the substrate in the subsequent
deposition process. The term "8 to 12 units long" denotes that for
polymer materials, its structure is chain-like, for example "8
unit" refer to the chain structure of C--C--C--C--C--C--C--C (C
means carbon, other bonds of carbon bond to the function group such
as hydrogen, --OH etc.)
[0033] The encapsulated magnetic nanocrystals 426 are then
transported into the deposition chamber 430 to be deposited onto
the substrate 431. As illustrated above, because the magnetic
nanocrystals 425 are crystallized before reaching the substrate
431, the magnetic nanocrystals 425 are usually a single domain.
Because the energy of the magnetic nanocrystals 425 is very low,
the encapsulated magnetic nanocrystals 426 will remain intact after
deposition onto the substrate.
[0034] An external magnetic field 432 is provided adjacent to the
substrate 431, which forms a relatively uniform magnetic field
direction as illustrated in FIG. 4. When the encapsulated magnetic
nanoclusters 426 reach the substrate 431, they will be aligned by
following the direction of the magnetic field 432 whilst depositing
on the substrate 431. The magnetic thin firm can then be formed
with highly oriented magnetic easy axis along a predetermined
direction controlled by the magnetic field 432.
[0035] FIGS. 5A and 5B show alternative configurations of a
magnetic field adjacent to a substrate for aligning the orientation
of the magnetic particles. In FIG. 5A, two permanent magnets or
electromagnets 537a and 537b are placed underneath a substrate 531.
The north magnetic pole of magnet 537a and the south magnetic pole
of magnet 537b are placed adjacent to the substrate 530 to generate
a magnetic field 520. The magnetic field 520 aligns the magnetic
particles along a direction parallel to the top surface 531a of the
substrate 531 during deposition. In addition, the substrate 531 and
the magnets 537a, 537b may be rotated during the deposition process
to achieve uniformity of the magnetic thin film deposition.
[0036] As shown in FIG. 5B, a circumferentially-oriented magnetic
field 540 may be obtained by passing through an electrical wire 538
through the center of the substrate 531. The magnetic field 540
aligns the magnetic clusters during deposition along a direction
parallel to and circumferential with respect to the a top surface
531a of the substrate 531.
[0037] As shown in FIG. 5C, a magnetic field 560 with a direction
perpendicular to a top surface 531a of the substrate 531 may be
obtained by placing a solenoid 539 around the substrate 531. The
solenoid aligns the magnetic particles during deposition along a
direction perpendicular to the substrate surface. It should be
appreciated that magnetic thin films having different magnetic
orientations may be obtained by applying an appropriate magnetic
field adjacent to the substrate.
[0038] FIG. 6 shows an apparatus for forming magnetic thin film
onto a substrate according to another embodiment of the present
invention. The apparatus comprises a cluster-forming chamber 610, a
heating chamber 620, an encapsulation chamber 629, and a deposition
chamber 630. In this embodiment, the encapsulation chamber 629 is
coupled between the cluster-forming chamber 610 and the heating
chamber 620.
[0039] The loosely bonded magnetic nanoclusters 624 formed by the
cluster-forming chamber 610 are transported into the encapsulation
chamber 629. A spray of organic solvent or surfactant 627 are
supplied by the nozzle 628 into the encapsulation chamber 629 to
mix with the magnetic nanoclusters 624 to form the encapsulated
nanoclusters 625.
[0040] The encapsulated nanoclusters 625 are transported into the
heating chamber 620 thereafter. The encapsulated nanoclusters 624a
are heated by the heaters 619 to a temperature of about 900.degree.
C. to form crystalized magnetic nanoclusters 626. At the same time,
the organic materials encapsulating the nanoclusters will be
carbonized by the heating process, therefore the crystallized
magnetic nanoclusters 626 are encapsulated with a layer of
amorphous carbon. The encapsulated magnetic nanoclusters are then
deposited onto the substrate 631 located in the deposition chamber
630.
[0041] FIG. 7 shows an apparatus for forming magnetic thin film
onto a substrate according to a further embodiment of the present
invention. The apparatus comprises a cluster-forming chamber 710, a
heating chamber 720 and a deposition chamber 730. In this
embodiment, the loosely bonded magnetic nanoclusters 724 are formed
in the cluster-forming chamber 710, and transported into the
heating chamber 720.
[0042] After heating in the heating chamber 720, the loosely bonded
nanoclusters 724 become close-packed and crystallized magnetic
nanoclusters 725. The magnetic nanoclusters 725 are then
transported into the deposition chamber 730 to be deposited onto
substrate 731. At the same time, non-magnetic materials are also
deposited onto the substrate 731 by a source 736. Examples of
non-magnetic materials that may be used include C, SiO.sub.2,
Si.sub.3N.sub.4 BN and/or carbon hydrogenate polymer.
[0043] FIG. 8 shows a method 800 for forming a thin film magnetic
recording media according to the present invention. In a first
block 802, magnetic nanoclusters are generated from a target. In a
next block 804, the magnetic nanoclusters are heated to a
crystallization temperature, whereby the magnetic nanoclusters are
crystallized so that to process necessary properties for data
storage purpose. Thereafter in a further block 806, the
crystallized magnetic nanoclusters mixed up with a non-magnetic
material. The non-magnetic material encapsulate the crystallized
magnetic nanoclusters and therefore, the intergranular coupling
effect of the magnetic particles will be reduced. In a next block
808, the encapsulated magnetic nanoclusters are disposed onto a
substrate to form solid-phase magnetic particles.
[0044] It should be appreciated that according to the above method,
since the desired crystalline structure are obtained before
deposition, the substrate after the magnetic nanoclusters deposited
thereon needs not be heated up for annealing purpose. Accordingly,
the grain growth by the post-deposition annealing is successfully
eliminated.
* * * * *