An assembly for accessing data bits in storage locations on a succession of radially separated tracks on a rotating multilayer MSR disc comprising a storage layer and a readout layer in combination with a slider flyable over a surface of the disc with the slider supporting at least one optical element coupled to the assembly, the optical element directing light to a region of the disc including one or more storage locations, with the optical element comprising an optical fiber and a micro-machined mirror supported on the slider and adapted to direct the light to storage locations on the recording layer of the disc, a conductive coil is coupled to and supported on the assembly, a passage of current through the conductor coil is sufficient to establish a magnetic field which is coupled to the disc and in cooperation with the light stores information at one of the storage locations on the storage layer, and a magneto-resistive element is coupled to the assembly, the magneto-resistive element cooperates with the light which illuminates and heats a plurality of the storage regions of the disc along one track of the disc, the magneto-resistive element senses one of the bits from the readout layer at the storage location.

FIELD OF THE INVENTION 
The present invention relates to heads for use in data storage and 
retrieval systems. 
BACKGROUND ART 
Magneto-resistive elements are well known in the art for use in magnetic 
disk drives. Recent advances in magnetic recording technology have 
provided magnetic heads using giant magneto-resistive (GMR) technology; 
see, for example, "Giant Magnetoresistance: A Primer," by Robert White, 
IEEE Transactions On Magnetics, Vol. 28, No. 5, September 1992, 
incorporated herein by reference. GMR heads may be manufactured to be 
about 5 times as sensitive to magnetic fields as conventional magneto 
resistive heads. GMR technology has also been incorporated with Spin-Valve 
structures that are well known in the art. 
Magneto-optical (MO) media includes data bits written as up or down 
magnetic domains perpendicular to the surface of the media. In prior art 
MO disk drives, data is read as a clockwise or counter-clockwise rotation 
imposed on a reflected polarized laser light by the up or down 
orientations of the domains. The polarization rotation information 
requires an optical readout means for detection of the rotated polarized 
light. In the prior art, the means for readout includes a plurality of 
bulky and complex optical elements located on a magneto-optical head (U.S. 
Pat. No. 5,295,122). In the prior art, the optical elements typically 
degrade the signal to noise ratio (SNR) of the information conveyed by the 
polarization rotation before readout as an electronic signal. The prior 
art optical elements also contribute to the mass of the magneto-optical 
head and to the complexity of the alignment between the optical elements. 
What is needed therefore is an apparatus that provides improved SNR readout 
for data stored with MO media and reduced mass and size of the associated 
magneto-optical head.

SUMMARY OF THE INVENTION 
The present invention utilizes magneto-resistive technology with 
magneto-optical technology. The present invention provides a signal 
representative of data recorded on a MO disk that has an improved SNR. The 
present invention minimizes the return optical path optics required by the 
prior art and thus the mass and complexity of an optical head. 
In the present invention at least one optical element is used to deliver 
light to a magneto-optical storage location. A current is applied to a 
conductor to cooperate with the light to store information at the 
magneto-optical storage location. In one embodiment, a flux guide enhances 
the storage of the information. In one embodiment, the at least one 
optical element includes an optical fiber and/or a steerable mirror. In 
the present invention, the at least one optical element is coupled to a 
magneto-optical head. 
In one embodiment the magneto-optical storage location includes a thermally 
assisted storage layer. A magneto-resistive element cooperates with the 
light for reading information at the magneto-optical storage location. In 
one embodiment, the magneto-resistive element is coupled to an air-bearing 
surface of the magneto-optical head. Alternatively, the magneto-resistive 
element is coupled to a flux guide to enhance the read signal obtained 
from the magneto-resistive element. In one embodiment, the flux guide is 
coupled to an optical element within a diameter and along a bottom surface 
of the optical element. The magneto-resistive element may include a 
conventional magneto-resistive element, a giant magneto-resistive element 
(GMR), or a Spin valve element. 
DESCRIPTION OF THE INVENTION 
The present invention provides a signal representative of the data recorded 
on the MO disk that has an improved SNR as compared to conventional MO 
data readout. In doing so, the present invention eliminates the return 
optical path optics required by the prior art and thus the mass and 
complexity of an optical head. 
Referring in detail now to the drawings wherein similar parts of the 
invention are identified by like reference numerals, there is seen in FIG. 
1 a diagram showing a magneto-optical data storage and retrieval system. 
In a preferred embodiment, a magneto-optical (MO) data storage and 
retrieval system 100 includes a set of Winchester-type flying heads 106 
that are adapted for use with a set of double-sided MO disks 107 (only one 
flying head and one MO disk shown). The set of flying heads 106 
(hereinafter referred to as flying MO heads) are coupled to a rotary 
actuator magnet and coil assembly 120 by a respective suspension 130 and 
actuator arm 105 so as to be positioned over upper and lower surfaces of 
the set of MO disks 107. In operation, the set of MO disks 107 are rotated 
by a spindle motor 195 so as to generate aerodynamic lift forces between 
the set of flying MO heads 106 and so as to maintain the set of flying MO 
heads 106 in a flying condition approximately 15 micro-inches above the 
upper and lower surfaces of the set of MO disks 107. The lift forces are 
opposed by equal and opposite spring forces applied by the set of 
suspensions 130. During non-operation, the set of flying MO heads 106 are 
maintained statically in a storage condition away from the surfaces of the 
set of MO disks 107. 
System 100 further includes: a laser-optics assembly 101, an optical switch 
104, and a set of optical fibers 102. The laser-optics assembly 101 
includes a polarized diode laser source 231 operating an optical power 
sufficient for writing and reading information using the set of MO disks 
107. The laser optics assembly 101 provides an outgoing laser beam 191 
(with reference to laser source 231) that passes through a polarizing beam 
splitter 161 and quarter-wave plate 163 before entering the optical switch 
104. In the exemplary embodiment, each of the set of optical fibers 102 
are coupled through a respective one of the set of actuator arms 105 and 
suspensions 130 to a respective one of the set of flying MO heads 106. As 
will be discussed shortly, the system 100 is used in a configuration that, 
compared to the prior art, improves access to, and storage of, 
magneto-optical information. 
FIG. 2 is a diagram showing a representative optical path. In a preferred 
embodiment, a representative optical path is shown in FIG. 2 to include: 
the optical switch 104, one of the set of optical fibers 102, and one of 
the set of flying MO heads 106. The optical switch 104 provides sufficient 
degrees of selectivity for directing the outgoing laser beam 191 (with 
reference to laser source 231) to enter a respective proximal end of a 
respective optical fiber 102. The outgoing laser beam 191 is directed by 
the optical fiber 102 to exit the optical fiber 102 so as to pass through 
the flying MO head 106 onto a surface recording/storage layer 349 of a 
respective MO disk 107. As described below, the MO disk 107 uses magnetic 
super-resolution (MSR) technology. 
During writing of information, the outgoing laser beam 191 is selectively 
routed by the optical switch 104 to the MO disk 107 so as to lower a 
coercivity of a recording/storage layer 349 by heating a selected spot of 
interest 340 to approximately the Curie point of the recording/storage 
layer 349. Preferably, the optical intensity of outgoing laser beam 191 is 
held constant, while a time varying vertical bias magnetic field is used 
to define a pattern of "up" or "down" magnetic domains perpendicular to 
the MO disk 107. This technique is known as magnetic field modulation 
(MFM). Subsequently, as the selected spot of interest 340 cools, 
information embodied in the magnetic field waveform is encoded within the 
recording/storage layer 349 of the respective spinning disk 107. 
During track following of data tracks on the MO disk 107, the outgoing 
laser beam 191 is reflected from the MO disk 107 as a reflected laser beam 
192 and is conveyed back by optical elements on the flying MO head 106, 
the optical fiber 102, and the optical switch to the laser optics assembly 
101 (FIG. 1). An amplitude of the reflected laser beam 192 passes through 
the quarter wave plate 163 and the polarizing beam splitter 161 and is 
used for deriving phase change track following signals for use by 
conventional phase change track-following circuitry (not shown). 
FIGS. 3a-f are diagrams showing the flying magneto-optical head of the 
magneto-optical data storage system in a perspective, a side 
cross-sectional, an expanded cross-section, a side, a front, a bottom, and 
a rear view, respectively. In FIG. 3a, the flying MO head 106 is shown for 
use above a surface recording layer 349 of one of the set of MO disks 107. 
The flying MO head 106 includes: a slider body 444, an air bearing surface 
447, a reflective substrate 400, objective optics 446, a conductor 460, 
and a flux guide 462. In one embodiment, the flux guide 462 includes a 
permalloy flux guide. The slider body 444 is dimensioned to accommodate 
the working distances between the objective optics 446, the optical fiber 
102, and the reflective substrate 400. The reflective substrate 400 may 
include a reflective surface which is aligned so as to direct the outgoing 
laser beam 191 to the surface recording/storage layer 349. Although, the 
slider body 444 may include industry standard "mini", "micro", "nano", or 
"pico" sliders, alternatively dimensioned slider bodies 444 may also be 
used. Accordingly, in the preferred embodiment, the slider body 444 
comprises a mini slider height (889 um) and a planar footprint area 
corresponding to that of a nano slider (1600.times.2032 um). 
The optical fiber 102 is coupled to the slider body 444 along an axial 
cutout 443, and the objective optics 446 is coupled to the slider body 444 
along a vertical corner cutout 411. Although in the preferred embodiment 
the axial cutout 443 is located along a periphery of the slider body, and 
the vertical cutout 411 is located at a corner of the slider body 444, the 
axial cutout 443 and the vertical cutout 411 may be located at other 
positions on the flying MO head 106, for example, between the periphery 
and a central axis of the flying MO head 106 or, alternatively, along the 
central axis itself. Those skilled in the art will recognize that 
positioning the optical fiber 102 and the objective optics 446 at other 
than along a central axis may function to affect a center of mass of the 
flying MO 106 and, thus, its flying dynamics. Accordingly, the point of 
attachment of the flying MO head 106 to the suspension may require 
adjustment to compensate for off-center changes in the center of mass of 
the flying MO head 106. Preferably, the cutouts 443 and 411 may be 
designed as channels, v-grooves, or any other suitable means for coupling 
and aligning the optical fiber 102 and objective optics 446 to the flying 
MO head 106. In the preferred embodiment, the outgoing laser beam 191 
traverses an optical path to the recording/storage layer 349 of the MO 
disk 107 that includes: the optical fiber 102, the reflective substrate 
400, and the objective optics 446. In the preferred embodiment, the 
optical fiber 102 and the objective optics 446 are positioned within their 
respective cutouts to achieve focus of the outgoing laser beam 191 within 
the spot of interest 340 as a focused optical spot 448. The optical fiber 
102 and the objective optics 446 may be subsequently secured in place by 
using ultraviolet curing epoxy or similar adhesive. 
As compared to free space delivery of laser light, the optical fiber 102 
provides an accurate means of alignment and delivery of the outgoing 191 
laser beam to the reflective substrate 400. The optical fiber 102 also 
provides a low mass and low profile optical path. The low mass of the 
optical fiber 102 provides a method of delivering light to the optics of 
the flying MO head 106 without interfering substantially with the 
operating characteristics of the actuator arm 105 and suspension 130. The 
low profile of the optical fiber 102 provides the ability to reduce the 
distance between a set of MO disks 107 without interfering with delivery 
of laser light to and from the MO disks 107 and/or operation of the flying 
MO head 106. The optical fiber 102 also appears as an aperture of a 
confocal optical system for the reflected laser beam 192 and has a large 
depth resolution along its optical axis and an improved transverse 
resolution. 
In an exemplary embodiment, the reflective substrate 400 may comprise a 
steerable micro-machined mirror assembly. A steerable micro-machined 
mirror assembly is disclosed in commonly assigned U.S. patent application 
Ser. No. 08/844,207, entitled "Data Storage System Having An Improved 
Surface Micro-Machined Mirror," which is was filed on Apr. 18, 1997 and 
which incorporated herein by reference. In the preferred embodiment, the 
steerable micro-machined mirror assembly 400 includes a small (in one 
embodiment, less than 300 um square) reflective central mirror portion 420 
(illustrated in FIG. 3a by dashed lines representative of the reflective 
central mirror portion on a side of the steerable micro-machined mirror 
assembly 400 opposite to that which is visible). The small size and mass 
of the steerable micro-machined mirror 400 contributes to the ability to 
design the flying MO head 106 with a low mass and a low profile. As used 
in the magneto-optical storage and retrieval system 100, fine tracking and 
short seeks to a series of nearby tracks may be performed by rotating the 
reflective central mirror portion 420 about a rotation axis so that the 
propagation angle of the outgoing laser beam 191 and the reflected laser 
beam 192 is changed before transmission to the objective optics 446. The 
reflective central mirror portion 420 is rotated by applying a 
differential voltage to a set of drive electrodes 404/405 (FIG. 3b). The 
differential voltage on the electrodes creates an electrostatic force that 
rotates the reflective central mirror portion 420 about a set of axial 
hinges 410 and enables the focused optical spot 448 to be moved in the 
radial direction of the MO disk 107. In the exemplary embodiment, a 
rotation of approximately .+-.2 degrees of the reflective central mirror 
portion 420 is used for movement of the focused optical spot 448 in an 
approximately radial direction 450 of the MO disk 107 (equivalent to 
approximately .+-.4 tracks) for storage of information, track following, 
and seeks from one data track to another data track. In other embodiments, 
other ranges of rotation of the reflective central mirror portion 420 are 
possible. Coarse tracking may be maintained by adjusting a current to the 
rotary actuator magnet and coil assembly 120 (FIG. 1). The track following 
signals used to follow a particular track of the MO disk 107 may be 
derived using combined coarse and fine tracking servo techniques that are 
well known in the art. For example, a sampled sector servo format may be 
used to define tracks. In the prior art, conventional multiple platter 
Winchester magnetic disk drives use a set of respective suspensions and 
actuator arms that move in tandem as one integral unit. Because each 
flying magnetic head of such an integral unit is fixed relative to another 
flying magnetic head, during track following of a particular magnetic disk 
surface simultaneous track following of another magnetic disk surface is 
not possible. In contrast, irrespective of the movement of the set of 
actuator arms 105 and set of suspensions 130, a set of the steerable 
micro-machined mirror assemblies 400 of the present invention may be used 
to operate independently and thus permit track following and seeks so as 
to read and/or write information using more than one MO disk surface at 
any given time. Independent track following and seeks using a set of 
concurrently operating steerable micro-machined assemblies 400 would 
preferably require a set of separate respective read channel and fine 
track electronics and mirror driving electronics. In the aforementioned 
embodiment, because delivery of the outgoing laser beam 191 would 
preferably require separate diode laser sources 231, an optical switch 104 
for switching between each of the separate optical paths would not 
necessarily be required. 
FIGS. 4a-c illustrate, a respective perspective section, side section, and 
exploded side section of the MO disk of the present invention. As was 
discussed above, the present invention transmits light to the set of MO 
disks 107 using low profile and small mass optical paths. The low profile 
and small mass optical paths enable the present invention to use a 
plurality of double sided first surface MO disks 107 at a very small 
spacing between disks. Unlike the prior art, the double-sided first 
surface MO disks 107 of the present invention utilize magnetically-induced 
super resolution (MSR) film structures. As compared to conventional 
quadrilayer MO disks, an MSR film structure can support readout of at 
least one data domain mark within any given optical spot 448 formed by the 
outgoing laser beam 191 on an MO disk 107 and, preferably a plurality of 
data domain marks. The MO disk 107 of the present invention utilizes 
thermally-induced masking of written magnetic domain patterns in the MSR 
film structure to enable extension of the modulation transfer function of 
the readout optical system. In the multi-layered recording/storage layer 
349 structure shown in FIGS. 4a-c, adjacent magnetic layers are coupled by 
an atomic exchange mechanism to form magnetic apertures, which are smaller 
than the optical beam size. There are several methods for selecting which 
magnetic domain within the illuminated area of the disk is selected and 
presented to the readout beam, mainly front-aperture detection (FAD), 
rear-aperture detection (RAD), and central-aperture detection (CAD). These 
methods differ in the location of the domain within the illuminated area 
of the disk which is selected for display to a magneto-resistive readout 
means discussed below. In the preferred embodiment, the CAD method is used 
for selection of a particular magnetic domain; however, it will be 
appreciated that the invention is not limited to this method. The CAD, 
FAD, and RAD methods are illustrated and discussed below with reference to 
FIG. 14 below. In these three techniques, data is written onto the storage 
layer 1371 with the flying MO head 106 flying close to the MO disk 107, 
which is modulated using the aforementioned MFM recording techniques. The 
dimensions of the conductor 460 and flux guide 462 (FIG. 3c) preferably do 
not interfere with passage of light through and to the objective optics 
446. The conductor 460 and flux guide 462 also provide the ability to 
record a plurality of magnetic domain marks that are smaller than the 
optical spot 448 size at a higher recording rate and higher flux density 
than the prior art. 
In an exemplary embodiment, the MO disk 107 is fabricated as a double sided 
first surface MSR media using storage layers 1364, 1365, and with embossed 
pits on opposing sides of a substrate 1366. Each layer preferably includes 
a lubricant/protective layer 1367 of a thickness approximately 3 nm. In 
one embodiment, the lubricant/protective layer 1367 may include a thin 
amorphous carbon film. Preferably, the lubricant/protective layer 1367 
includes a transmittance of at least 0.95. The lubricant/protective layer 
preferably facilitates dynamic load and unload of the flying MO head 106 
to and from the flying condition, and also supports long term stability 
during track-following and track seeking. The lubricant/protective layer 
1367 also provides an anti-static function to keep the MO disk 107 surface 
resistivity below 10.sup.12 /ohms. The lubricant/protective layer 1367 is 
deposited over a silicon nitride (SiN) upper dielectric layer 1368. 
Although in an alternative embodiment, the lubricant/protective layer 1367 
can provide a protective function, in the exemplary embodiment, the 
dielectric layer 1368 also serves this function. The upper dielectric 
layer 1368 includes a thickness typically in the range of 60-100 nm. The 
upper dielectric layer 1368 acts to provide a number of functions, 
including: (a) a hard protective coating to prevent film damage during 
disk handling or inadvertent head-disk contact during device operation; 
(b) thickness, refractive index, and thermal properties that adjust for 
the reflectance and Kerr effect properties of the layers below; (c) 
sufficient impermeability to protect and passivate the chemically active 
MO layers below. The upper dielectric layer 1368 is deposited over a 
plurality of magnetically active layers 1369 and 1371 that have a total 
thickness of approximately 40-100 nm. The layers 1369 and 1371 preferably 
function to yield a readout aperture with a read power of preferably less 
than approximately 3 mW. The upper layer 1369 is a read layer and is 
approximately 40 nm thick to preferably yield a strong Kerr effect and 
maximal signal-to-noise performance. In an exemplary embodiment, the upper 
layer 1369 is a ferrimagnetic material such as GdFeCo. In the exemplary 
embodiment, the lower layer 1371 is data storage layer comprised of a 
ferrimagnetic alloy such as DyFeCo having a thickness of approximately 40 
nm. In both layers 1369 and 1371, each magnetic data domain consists of a 
region of the layer that is magnetized in a perpendicular direction to the 
surface of the MO disk 107. The upper 1369 and lower 1371 layers 
preferably have a low transmittance such that an optical reflective 
function is provided by only the layers above. This compares favorably to 
traditional quadrilayer MO disk media, in that, a separate reflective 
layer is not necessarily required. The lower layer 1371 is deposited on 
top of a silicon nitride dielectric layer 1372 that has a thickness of 
approximately 20-40 nm. The lower dielectric layer 1372 is disposed on the 
substrate 1366. The thickness of the various layers of the MO disk 107 are 
preferably selected for proper thermal behavior (appropriate power 
sensitivity and good temperature gradients for writing and for sharp MSR 
aperture formation) and for good exchange coupling. 
In an exemplary embodiment, the substrate 1366 may be a single piece metal 
such as Aluminum Magnesium (AlMg) or, for alternatively, a plastic, a 
glass, a ceramic substrate, or a two-piece laminated plastic substrate. It 
is understood, however, that other materials for the substrate 1366 are 
within the scope of the present invention. The substrate 1366 should be 
sufficiently rigid to resist deformation when the MO disk is spun at 4500 
rpm. The substrate 1366 thickness is preferably in a range of 1.20.+-.0.05 
mm. If a plastic substrate is used, a thermal heat sinking layer may be 
deposited directly on the substrate 1366 to control lateral heat flow, for 
example a metallic layer. If a metal substrate is selected, a hard 
overcoat such as nickel phosphorous (NiP) may be deposited on the 
substrate 1366 before the deposition of the dielectric layer 1372. The 
overcoat should have a sufficiently low thermal conductivity such that it 
does not degrade the writing sensitivity of the disk (i.e., elevate the 
writing/reading/erasing power requirement). If a plastic is selected, 
tracking and format information may be embossed ("hard formatting"). If a 
metal or glass substrate is selected, mass replicated format features 
(e.g., photopolymerization) may be used. Alternatively, "soft formatting" 
by magnetic layer writing may be used. 
In an alternative exemplary embodiment, the layers 1369 and 1371 may be 
separated by a magnetic or non magnetic coupling layer (not shown) so as 
to improve exchange coupling. In another alternative exemplary embodiment, 
the layers 1369 and 1371 may comprise multi-layers deposited contiguously, 
or separated by intervening dielectric layers, depending on the interlayer 
magnetic coupling and resultant MSR performance desired. 
FIG. 5 illustrates a temperature profile of the CAD MSR recording method. 
With the CAD method mentioned above, MSR creates an essentially 
elliptically shaped aperture 1470 inside of a particular isotherm in the 
read layer 1369 due to an elevated temperature profile created by the 
outgoing laser beam 191. By carefully designing the MO film composition, 
stack architecture, and thickness, the temperature profile 1483 can be 
tailored for a desired power sensitivity as well as signal and noise 
performance. The aperture 1470 includes a high temperature zone in which a 
particular data domain mark recorded in the storage layer 1371 is copied 
upward to the read layer 1369. The copying is a parallel coupling of the 
perpendicular magnetization (to the disk plane) of a particular data 
domain mark 1413 in the storage layer 1371 to the magnetization of the 
read layer 1369. Near room temperature, no data domain marks 1413 are 
available for readout. During readout, when a magnetization between layers 
is induced by temperature elevation by application of the outgoing laser 
beam 191, a relatively strong vertical magnetic flux signal is available 
only for the data mark 1413 not masked by the aperture for the outgoing 
laser beam 191 incident on the read layer 1369. The CAD method is 
advantageous for a number of reasons, including: the aperture shape is 
easily controlled by the level of readout laser power (typically 2-3 mW); 
the aperture shape masks not only magnetization information that would 
otherwise interfere with the data marks to be read along the data track, 
but it also shields adjacent track information, thus enabling higher track 
and linear densities; no readout magnetic field is required; and the read 
layer and write layer structure is relatively simple. 
The present invention identifies that the magneto-optical data storage and 
retrieval system 100 may achieve high SNR readout of the vertical flux 
field generated by the data domain marks 1413 on a MO disk 107 by taking 
advantage of magnetic head recording technology. This contrasts to prior 
art MO data readout, in which polarization rotation of a readout optical 
beam is used to detect the up or down orientations of the data marks 
stored on a conventional MO disk. The present invention further identifies 
that use of magneto-resistive head technology combined with MSR technology 
provides the ability to record and readout high data densities. 
FIG. 6 is a perspective view of an embodiment of the flux guide 462 
illustrated in FIGS. 3c and 3d. In one embodiment, the flux guide 462 
includes a left portion 527 and a right portion 525. The left and right 
portions 527, 525 are each defined by a C-shaped semi-cylinder that is 
symmetric with respect to a generally longitudinal axis passing 
therethrough. The left and right portions 527, 525 each include an inner 
edge 559 and an outer edge 516. The left and the right portions 527, 525 
are positioned such that the inner edges 559 are disposed to be 
approximately parallel to each other and separated by a gap of 
approximately 15 um. It is understood, however, that the gap may include 
other dimensions. The gap between the inner and outer edges 559 and 516 
defines a passage through which the outgoing laser beam 191 may be scanned 
back and forth onto the MO disk 107 (shown as arrow 450). The C-shaped 
semi-cylinder defines a volume within which the conductor 460 (FIG. 3c) is 
disposed. It is understood, however, that the left 527 and right 525 
portions may define other volumes comprising other geometries. In one 
embodiment, the conductor 460 is a coiled conductor (only two turns 
shown). A passage of current though the conductor creates a sufficient 
magnetic field for writing data marks 1413 at the surface of the MO disk 
107. The flux guide 462 enhances the aforementioned magnetic field. 
In one embodiment, the left and right portions 527, 525 each include a 
generally flat top portion and a generally rectangular channel 614 formed 
therein. In the preferred embodiment, the left and right portions 527, 525 
further include a magneto-resistive element 594. In the preferred 
embodiment, the magneto-resistive element 594 is deposited within the 
channel 614 using magneto-resistive thin film and planar deposition 
technologies well known in the art. In one embodiment, the 
magneto-resistive element may include a giant magneto-resistance (GMR) 
element. In another embodiment, the magneto-resistance element may include 
a Spin Valve element. Other magneto-resistive elements are also within the 
scope of the present, for example, single or dual stripe 
magneto-resistance elements. In the preferred embodiment, the 
magneto-resistive element 594 includes a rectangular linear strip type 
design used in prior art magnetic head designs. It is understood that the 
magneto-resistive element 594 requires biasing (not shown) using 
techniques that are well known in the art. The dimensions of the 
magneto-resistive element 594 includes a length, a width and a height, 
with the width being less than the length, and the height being less than 
the width. During reading of data, the left and right portions 527, 525 of 
the flux guide 462 direct the flux formed within the MSR aperture 1470 
(described above) by any particular data domain mark 1413 towards and 
through the magneto-resistive element 594. The magneto-resistive element 
594 is preferably oriented to pass and sense the flux (F) along the width 
of the magneto-resistive element 594. The left and right portions are 
electrically connected (connection 677) such that a change in the flux F 
changes a series resistance of the magneto-resistive elements 594. The 
series resistance is sensed at a set of outputs X.sub.1 and X.sub.2 and is 
amplified by a conventional magneto-resistive preamplifier (not shown) 
into a signal representative of up or down orientations of the data domain 
marks 1413. In the embodiment illustrated in FIGS. 3c and 3b, the flux 
guide 462 (and therefore the magneto-resistive elements 594) are 
dimensioned to be of a size that may be coupled within an outer diameter 
(in one embodiment, 0.250 um) and lower surface of the objective optics 
446. In contrast to the use of conventional magneto-resistive elements, a 
GMR element provides increased sensitivity to magnetic flux generated by 
data domain marks 1413 and, therefore, permits an increased flying height 
of the flying MO head 106 above the MO disk 107. It is understood that 
increased sensitivity to the magnetic flux generated by a particular data 
domain mark 1413 may be achieved by positioning the magneto-resistive 
element 594 at other than a top portion of the flux guide 462, for 
instance, within channels 615 formed more generally towards the inner 559 
or outer edges 516. In an alternative embodiment, a magneto-resistive 
element 594 may be used only in either the left or right portions 527, 
525. In the aforementioned alternative embodiment, the MSR aperture 1470 
formed by the outgoing laser beam 191 may alternatively be tear-dropped 
shaped (illustrated by dashed lines) rather than elongated (the shape of 
the aperture being a function of the material properties of the various 
layers deposited on the MO disk 107). Thus, during data readout (during 
rotation of the MO disk 107), the MSR aperture 1470 would extend towards 
the magneto-resistive element 594 as the flying MO head 106 passes over 
the narrow tail end of the tear-dropped aperture flux emanating from a 
particular data domain mark of interest within the aperture. In other 
words the optical spot gives radial resolution and the magneto-resistive 
element gives circumferential resolution. 
While the aforementioned description has been directed to a read/write 
magneto-optical system, it is understood that in a read only system a 
coiled conductor 460 and flux guide 462 would not be necessarily required. 
It is understood that in other embodiments the MO disk 107 could include 
other MO media structures. With position sensing patterns that are 
magnetically written, rather than servo pits, the present invention may be 
used to track follow data tracks by using the magneto-resistive element 
594 with conventional magnetic head track following circuitry. In the 
aforementioned embodiment, a servo pattern would be pre-recorded on the MO 
disk 107 using techniques well known in the magnetic disk arts. It is 
understood that the flux guide 462 and conductor 460 (and thus the gap 
formed between the left portion 527 and the right portion 525) could 
include other geometries, for example circular, elongated, rectangular, 
etc. (a crossection of a circular flux guide is shown in FIG. 7). In an 
alternative embodiment shown in FIG. 7, the magneto-resistive element 594 
is shown to be disposed along an inner tip 559 of a circular flux guide. 
An opposing magneto-resistive element could also be disposed in the 
portion of the circular flux guide not shown in a crossection. It is 
understood that magneto-resistive elements 594 could be disposed (as in 
the embodiment shown in FIG. 6) along a flat top portion of the circular 
flux guide 462. It is also understood that in one embodiment, the 
reflective substrate 400 may include a fixed reflective central mirror 
portion 420. In this latter embodiment, a two stage head actuator (for 
example, as disclosed by Horsely et al. in "Angular Micropositioner For 
Disk Drives, starting on Pg. 454, in IEEE Proceedings, Tenth Annual 
International Workshop On Micro Electro Mechanical Systems, Jan. 26-30, 
1997), herein incorporated by reference, could be used to track follow a 
surface of a MO disk 107. In other embodiments, it is understood that a 
data domain marks 1413 could be written by a conductor 460 without 
necessarily requiring a flux guide 462 to guide the flux to the MO disk 
107. In the aforementioned embodiment, the magneto-resistive element 594 
could be disposed within a channel 428 (FIG. 3f) along the air bearing 
surface 447 of the flying MO head 106. It is further understood that if a 
laser diode laser source 231 were to be located on each of the set of MO 
heads 107, the optical fibers 102 and the optical switch 104 would not 
necessarily be required. 
Thus, while the present invention has been described herein with reference 
to particular embodiments thereof, a latitude of modification, various 
changes and substitutions are intended in the foregoing disclosure, and it 
will be appreciated that in some instances some features of the invention 
will be employed without a corresponding use of other features without 
departure from the scope of the invention as set forth.