Integrated Heat Assisted Magnetic Recording Head: Design & Recording Demonstration

Transcription

1 > FOR CONFERENCE-RELATED PAPERS, REPLACE THIS LINE WITH YOUR SESSION NUMBER, E.G., AB-2 (DOUBLE-CLICK HERE) < 1 Integrated Heat Assisted Magnetic Recording Head: Design & Recording Demonstration Michael A. Seigler, Member, IEEE, William A. Challener, Edward Gage, Nils Gokemeijer, Ganping Ju, Bin Lu, Member, IEEE, Kalman Pelhos, Chubing Peng, Robert E. Rottmayer, Xiaomin Yang, Hua Zhou, Tim Rausch Abstract Scaling the areal density, while maintaining a proper balance between media signal-to-noise, thermal stability and writability will soon require an alternative recording technology. Heat Assisted Magnetic Recording (HAMR) can achieve this balance by allowing high anisotropy media to be written by heating the media during the writing process (e.g. by laser light) to temporarily lower the anisotropy. Three major challenges of designing a HAMR head that tightly focuses light and collocates it with the magnetic field are discussed: 1) Magnetic Field Delivery, 2) Optical Delivery, and 3) Magnetic & Optical Field Delivery Integration. Thousands of these HAMR heads were built into sliders and HGAs, and optical and scanning electron micrograph images are shown. Scanning near-field optical microscopy (SNOM) characterization of the HAMR head shows that the predicted ~λ/4 full-width half-maximum (FWHM) spot size can be achieved using 488 nm light (124 nm was achieved). SNOM images also show that wafer level fabricated apertures were able to effectively eliminate sidelobes from the focused spot intensity profile. An MFM image of HAMR media shows that Non-HAMR (laser power off) was not able to write transitions in the HAMR specific media even at very high write currents, but transitions could be written using HAMR (laser power on), even at lower write currents. A cross-track profile is shown for a fully integrated HAMR head where the magnetic pole physical width is ~35 nm, but the written track is ~2nm, which demonstrates HAMR. A HAMR optimization contour shows that there is an optimum write current and laser power and that simply going to the highest write current and laser power does not lead to the best recording. Lastly, some prospects for advancing HAMR are given and a few key problems to be solved are mentioned. Tesla at room temperature, scaling the areal density, while maintaining a proper balance between these three parameters, will require an alternative technology, such as Heat Assisted Magnetic Recording (HAMR). HAMR heats the magnetic media to alter the intrinsic magnetic properties such as the magnetic anisotropy and saturation magnetization [1]. These parameters drop continuously to nearly zero when a magnetic material is heated to its Curie temperature. The HAMR writing process uses this effect by heating the media to a temperature where coercivity is below the magnetic field applied by the write head. The heated region is then rapidly cooled to ambient temperature while the head field is applied. As long as the head field is larger than the local demagnetization fields from the nearby media, the magnetization of the media grains will Coercivity Storage Temp. Cooling Media Available Head Field Temperature Heating Media Write Temp. Index Terms Heat Assisted Magnetic Recording, HAMR, Magnetic Recording, Recording Head I I. INTRODUCTION n order to scale the areal density in magnetic recording, one must maintain the balance in media signal-to-noise (SNR), thermal stability and writability. Due to the lack of magnetic materials with a saturation magnetization above ~2.4 Manuscript received May 31, 27. This work was performed as part of the Information Storage Industry Consortium (INSIC) program in Heat Assisted Magnetic Recording (HAMR), with the support of the U. S. Department of Commerce, National Institute of Standards and Technology, Advanced Technology Program, Cooperative Agreement Number 7NANB1H356 The authors are with Seagate Technology, Pittsburgh, PA USA (phone: ; mike.a.seigler@seagate.com). (c) (d) Fig. 1. Diagram showing the HAMR writing process. Cross-sectional and (c) top down diagrams of a HAMR head that combines a PSIM with an input coupling grating and a magnetic recording ring head. (d) is a legend for and (c).

2 > FOR CONFERENCE-RELATED PAPERS, REPLACE THIS LINE WITH YOUR SESSION NUMBER, E.G., AB-2 (DOUBLE-CLICK HERE) < 2 be oriented in the direction of the applied head field. A sketch illustrating the HAMR writing process is shown in Fig. 1. II. INTEGRATED HAMR HEAD DESIGN The following three major challenges for the HAMR head design and process will be addressed here: 1) Magnetic Field Delivery, 2) Optical Delivery, and 3) Integration of Magnetic & Optical Field Delivery Components.. A. Magnetic Field Delivery The first challenge can be addressed with a magnetic field delivery similar to that used in conventional magnetic recording heads. The basic design is a current carrying coil wrapped around a magnetic core that is patterned down to ~1-3 nm where it is in close proximity to the media, see Fig. 1 [2]. A few modifications need to be made that affect the performance of the head, due to some of the limitations imposed by the HAMR recording system. Some examples are: 1) The magnetic pole material will need to remain far from the waveguide (WG) core and need to be brought into close proximity to the WG for a very short distance. This will allow a large magnetic field to be collocated with the thermal spot in the media, yet not cause large optical losses in the WG. 2) The media is moving from right to left in Fig. 1. The media must pass through the optical spot before reaching the magnetic field, which requires writing with the front edge of the pole. If the bit were to be written and then pass through the peak of the thermal spot, the bit could become unstable or erased. 3) In order to achieve good thermal stability at high areal densities, perpendicular media will be used, so a perpendicular field component is needed. This requires the WG core to be offset in the gap of the head. In order to limit the maximum required temperature (which requires more power and generates more thermal stresses on the head and media), the largest magnetic field possible is desired. This is can be achieved by using high moment materials, such as Fe 6 Co 4 and by optimizing the pole design. Due to the need for a good thermal heat sink to constrain the lateral heat flow in the media and to improve the thermal response time of the media, using a soft under layer (SUL) is not easily done. If a SUL can be used, the head design may need to be changed to utilize the benefits of the SUL. B. Optical Delivery The second challenge can be addressed using a Planar Solid Immersion Mirror (PSIM) to form a diffraction limited focal spot, see Fig. 1(c) [3,4,5,6,7] and Fig. 2. The PSIM consists of a planar WG, which is a high index of refraction (n) layer sandwiched between two low n layers. A grating for coupling light into the WG can be formed in the core of the WG using standard lithography and vacuum etching. The planar WG can be patterned into the shape of a parabola, also using standard lithography and vacuum etching, and a metal can be deposited onto the sidewalls of the parabolic WG to enhance the reflectivity. The PSIM sidewall needs to be nearly vertical /e Propagation (µm) 1/e (intensity) % Transmitted 1% 8% 6% 4% 2% 1E K of Waveguide Material Fig. 2. Diagram of a planar WG with a grating coupler and PSIM focusing. 1/e propagation length versus the imaginary part of the index of refraction for an alumina / tantala / alumina planar WG. and optically smooth so that it does not reflect the light out of the WG. When the light strikes the edge of the parabola, the light is reflected and focused at the focal point of the parabola. The width of the spot in the plane of the WG determines the data track width. The mode confinement in the WG will, in part, determine the down-track thermal gradient. C. Magnetic & Optical Field Delivery Integration Maxwell s equations for a planar WG can be solved to calculate parameters such as: 1) The electric field profile in the WG, 2) The effective index of the WG (or mode index), and 3) The rate at which the light power is lost as it propagates through the WG [8]. Fig. 2 shows the 1/e propagation length for the light intensity versus the imaginary part of the index of refraction (k) if the planar WG consists of alumina (n~1.67) and tantala (n~2.25) as the cladding and core layers respectively, and it is assumed that k is the same for both materials. This graph also shows what percentage of the light would propagate across a 1µm device. It can be seen that high quality optical materials are needed for the HAMR head (k < 1x1-4 ). The Transverse Electric (TE) and Transverse Magnetic (TM) modes in this WG have nearly identical losses and are not distinguishable on this graph, so only the TE data was graphed. For this planar WG, the mode index is ~1.9, which predicts that a spot width of ~λ / 4 can be achieved. Since the NA > 1, the high spatial frequency components of the light that produce the small spot, do not propagate in air. Therefore, the PSIM needs to be held in close proximity to the media so that the evanescent waves can couple from the PSIM to the media before they decay. This can be achieved with the standard magnetic recording slider % % Transmitted 1µm

3 > FOR CONFERENCE-RELATED PAPERS, REPLACE THIS LINE WITH YOUR SESSION NUMBER, E.G., AB-2 (DOUBLE-CLICK HERE) < 3 that flies above the media and keeps the head-to-media spacing < 25nm. The third challenge is difficult due to Fe, Co, Ni and their alloys being poor optical materials, and there not being any known high magnetic moment, optically transparent materials. Fig. 3 shows a diagram of the alumina / tantala / alumina WG with the pole material in close proximity to the WG. The 1/e propagation loss was calculated versus the alumina spacer thickness for Fe, Co, Ni and Al, and the data is shown in Fig. 3. Aluminum is included to show the results for a good optical material at λ=488 nm. Fig. 3 also shows the 1/e propagation length for Co and the percent of the light power that is absorbed by a.5µm high Co pole. A large absorbed power will require a more powerful laser and it will result in a higher write pole temperature, which can lead to pole tip protrusion and degraded magnetics. In order to evaluate the total light blocked by the pole, the percentage of light reflected by the pole also needs to be considered. Using the same calculations as above, the electric field and intensity mode profiles can be calculated for modes propagating in the WG with different spacings. Fig. 4 shows a series of intensity profiles for no pole and spacings from to 1 nm. When there is no pole present, the intensity profile is symmetric with respect to the core of the WG, which is drawn on the graph and is in the same relative position for all the intensity profiles. When the Co pole is brought into close proximity to the WG, the intensity profile is shifted away from the pole and more of the light power propagates in the alumina cladding layer. The position of the alumina spacer and the Co pole are drawn on the graph for the 1nm spacer case, but the alumina spacer thickness and the subsequent location of the Co pole is different for each 1/e Propagation (μm) Co Pole Alumina Spacer I Tantala Core Alumina Cladding Fe Co Ni Al % Abs. 35% 3% 25% 2% 15% 1% Pole-to-WG Core Spacing (nm) Fig. 3. Diagram of a planar WG consisting of ~1µm bottom alumina \ ~8 nm tantala core \ alumina spacer \ pole material. Optical Loss for this WG, where the top alumina is used to adjust the spacing between the WG core and the pole material and % of light absorbed by a 5 nm high Co pole. 5% % % Absorbed_Co Pole intensity profile. The overlap between the mode profile without a pole, and the mode profiles for each of the different spacings, can be used to estimate the percent of light that is reflected as the light attempts to propagate from the region without a pole to the region with a pole. These results can then be combined with the absorbed power results from above to give a total amount of light blocked by the pole, see Fig. 4. The Reflected line shows the percentage of incoming light that is reflected, and the WG Under Pole line shows the percentage of light that is absorbed by a 5 nm high Co pole. The Total Lost line shows the percentage of incoming light that does not make it to the ABS. Once these loss values are combined, it begins to become obvious why it is difficult to integrate the magnetic and optical field delivery components. Fig. 5 shows the head magnetic field components and media coercivity, both versus the down track direction. The magnetic field components for the head shown in Fig. 1 were estimated using the Karlkvist approximation. Hy is perpendicular to the media, Hx is in the down track direction and Heff is the Stoner-Wohlfarth effective field (Heff = (Hx 2/3 + Hy 2/3 + Hz 2/3 ) 3/2. The deep gap field in the Karlkvist approximation was set to 7 Oe, which was the value needed such that the Stoner-Wohlfarth Heff was the same as that obtained by finite element modeling. The head-to-media separation was set to 1 nm and the gap length was set to 1µm. The edge of the pole is located at 5 nm. The thermal profile is assumed to be Gaussian with a full width half maximum (FWHM) that is the same as the optical spot FWHM (λ/4 = 488nm / 4 = 122nm). The actual relation between the optical and thermal profiles depends heavily on the thermal structure of the media, such as heatsinking. The Normalized Intensity (a.u.). % Lost % 8% 6% 4% 2% % No Pole nm Spacer 15 nm Spacer 5 nm Spacer 1 nm Spacer Alumina Cladding Tantala Alumina Spacer Co Pole Core Waveguide Cross-section (nm) (TE Mode, 488nm, λ=5nm Co Pole) WG Under Pole Reflected Total Lost P2A-to-Core Spacer (nm) Fig. 4. Intensity profiles in the WG for different core-to-pole spacings. Light power blocked by the pole versus core-to-pole spacings.

4 > FOR CONFERENCE-RELATED PAPERS, REPLACE THIS LINE WITH YOUR SESSION NUMBER, E.G., AB-2 (DOUBLE-CLICK HERE) < 4 maximum temperature was set equal to the Curie temperature (Tc) of the media (77 K). The peak in the temperature was assumed to be at the center of the WG core, so it was located 14 nm from the edge of the pole (1 nm spacing + 4 nm for ½ the WG core thickness). The media parameters for FePt were taken from reference [9] for Fe 55 Pt 45. Hk was set to 82 koe and Tc was set to 77 K. The point where Heff or Hy become greater than the media Hk, the Ms will be <25% of the Ms at room temperature. With the resulting large angular distribution of the magnetization, and considering the dynamics involved, it is not clear if Heff or Hy, or some combination of the two, is the important field parameter to compare to Hk. The media will be moving from right to left, so the last point where the media Hk becomes greater than Heff or Hy is where the magnetic transition will be written. For the following evaluations of the field gradients, it will be assumed that the transition is written where Hk = Heff. In Fig. 5, the location of the thermal profile is shown as a solid line (marked by a ) for a 1 nm spacer and the Hk = Heff point is circled. At this point, dhy/dx = -22 Oe/nm, dheff/dx = -31/nm and dhk/dx = -113 Oe/nm. It is unfortunate that all the gradients are negative, so the magnetic field and thermal gradients are working against one another. Fortunately, the dhk/dx gradient dominates the magnetic field gradient; due to the large anisotropy of the FePt media and sharp thermal gradient. At the optimum spacing (2 nm between the pole edge and thermal peak), the gradients are sharp and add, dhk/dx = Oe/nm, dheff/dx = 438 Oe/nm and the combined gradients dheff/dx dhk/dx = 1541 Oe/nm. Of course, the 2 nm spacing will be difficult to achieve, per the issues described above. D. HAMR Head Fabrication There are three general modes of HAMR operation: 1) broad magnetic field & focused optical spot, 2) narrow magnetic field & broad optical spot, and 3) narrow magnetic field & focused optical spot. Having either a broad magnetic field or optical spot may cause aging of the adjacent tracks, but having a narrow magnetic field and focused spot makes alignment of the two difficult. The first mode of operation above is investigated here, with the intention that the broad magnetic field won t erase the adjacent tracks due to their large Hk when not being heated. Thousands of HAMR heads as shown in Fig. 1 were fabricated using standard thin-film processing, Hk 6 Hy 5 4 Hx 3 Heff 2 Hk (opt.) Down Track (nm) Fig. 5. Overlay of Karlkvist head fields and media anisotropy H (koe) similar to that used to build conventional magnetic recording heads. Some of these heads were then built into sliders and lapped such that the focal point of the PSIM was located at the ABS. Fig. 6 shows a scanning electron microscope (SEM) image of the ABS of one of the heads. Fig. 6 shows an optical image of a fully integrated HAMR head with the 488 nm laser light coupled into the WG while the image was taken, so the focused optical spot is visible at the ABS. It can be seen that the optical spot profile has a central spot and sidelobes. Fig. 6(c) shows an optical image of a fully integrated HAMR head with an aperture fabricated to block the optical side lobes, and the majority of the sidelobes have been blocked. The ABS was imaged using scanning nearfield optical microscopy (SNOM). Fig. 7 shows a SNOM image of an optical only head (no magnetic poles and no aperture) and Fig. 7 shows a SNOM image for a fully integrated HAMR head with apertures. The focal spot width (in the cross-track direction) was found to have a FWHM of PSIM Aperture (c) Magnetic Poles Magnetic Pole Reader Side Lobes WG Core Focused Laser Spot Fig. 6. ABS view scanning electron micrograph of a HAMR head without an aperture, ABS view optical image of a HAMR head with the light coupled into the WG, and (c) ABS view optical image of a HAMR head with an aperture and with the light coupled into the WG.

5 > FOR CONFERENCE-RELATED PAPERS, REPLACE THIS LINE WITH YOUR SESSION NUMBER, E.G., AB-2 (DOUBLE-CLICK HERE) < 5 5 ND19843, ND19843, IY bar: IY J bar: device, J device, SIM 2 SIM-2 nm nm 4 Intensity (a.u.) No Poles SIM or Only Aperture Head 124 nm 124 nm Cross-Track (µm) Non-HAMR I=12mA I=7mA th a ND26567, Top IW Pole bar: L device, & CDSEM: Apertu corrup Intensity (a.u.) With Pole & Apertures nm nm Cross-Track (µm) HAMR nm I=7mA Fig. 7. SNOM images of the ABS of a HAMR head with not poles and no aperture and with the magnetic write poles and with an aperture. (c) Magnetic force microscopy image of high coercivity media being written without heat assist and with heat assist. 124 nm for the PSIM only head, which is almost exactly λ/4 for the 488 nm light used. Side lobes are also clearly visible in this image. The spot was slightly larger when the magnetic poles were included, with a FWHM of 14 nm, which is probably due to a different SNOM tip being used which does affect the measurement result. With the apertures in place, the side lobes were significantly reduced. These HAMR sliders were then fabricated into head gimbal assemblies (HGAs) for HAMR spin-stand testing. E. HAMR Head Testing The fully integrated HAMR HGAs were then tested on a specially designed HAMR spin-stand [1] that allows for full operation of the magnetic read and write head while the 488 nm laser light is coupled into the WG. The media used was a HAMR unique media, such as a high coercivity CoPt multilayer with a special thermal design that could not be written with conventional magnetic recording. Fig. 7 shows a magnetic force microscopy (MFM) image of the media after both Non-HAMR (no laser power) and HAMR writing. It can be seen that with a write current of 7 ma no transitions were written using Non-HAMR recording, columns 1 Fig. 7. When the write current was turned up to 12 ma, the media may have been slightly perturbed, but there are still no clear transitions written, column 2 in Fig. 7. Once the laser was turned on for HAMR recording, bits were easily written with a 7 ma write current, columns 3 through 7 in Fig. 7. Columns 3, 5 and 7 are tones at increasing linear densities. Columns 4 and 6 are pseudorandom bit sequences at increasing frequencies. The rather straight transitions may indicate that (c) recording is not completely dominated by the thermal gradient and that the magnetic gradient is still playing a significant role. Fig. 8 shows an auto correlated signal-to-noise (ACSN) cross-track profile that was taken with a fully integrated HAMR head. The is done by writing a bit sequence with the fully integrated HAMR writer and then scanning the reader across the track, thus the resulting profile is a convolution of the write and read profiles. The physical width of the magnetic top pole on this particular head was ~35 nm. The optical or thermal spots can not be measured during the testing, but the optical spot FWHM should have been ~14 nm, similar to the measurement shown in Fig. 7. It can be seen that the written track width is significantly narrower than the physical pole width, which is an indication of HAMR. Fig. 8 shows an optimization contour taken with a fully integrated HAMR head. The z-axis in this plot is ACSN. It can be seen that with too low of a laser power or too low of a write current, the media can not be written. If the laser power it too low, the media anisotropy is not reduced far enough to be written by the head. If the write current is too low, the head is not producing enough field to either overcome the media anisotropy or the demagnetization fields of the surrounding media. If the laser power is turned up too high, the thermal FWHM becomes too large and the writing occurs somewhere away from the front face of the top pole, where the field and field gradient are relatively small. It can also be Laser Power ACSN (db) (db) Cross-Track Position (nm) Cross-Track Position (nm) Write Current Fig. 8. ACSN cross-track profile, where the track was written by a fully integrated HAMR head and readback with the reader on that same head. Contour plot showing the HAMR recording optimization using a fully integrated HAMR head.

6 1 R. E. Rottmayer, S. Batra, D. Buechel, W. A. Challener, J. Hohlfeld, Y. Kubota, L. Li, B. Lu, C. Mihalcea, K. Mountfield, K. Pelhos, C. Peng, T. Rausch, M. A. Seigler, D. Weller, and X. Yang, Heat-Assisted Magnetic Recording, IEEE Trans. Magn. Vol. 42, No. 1, (26) 2 M. A. Seigler, T. W. Clinton, M. W. Covington, and C. D. Mihalcea, Data writing with plasmon resonator, US Patent Application W. A. Challener, C. D. Mihalcea, T. Rausch, Apparatus and method for producing a small spot of optical energy, US Patent 6,795,63 4 W. Challener, C. Mihalcea, C. Peng, and K. Pelhos, Miniature planar solid immersion mirror with focused spot less than a quarter wavelength, Opt. Exp., vol. 13, no. 18, pp , (25). 5 C. Peng, C. Mihalcea, D. Buechel, W. Challener and E. Gage, Near field optical recording with a planar solid immersion mirror, APL, vol. 87, pp T. Rausch, et al., Near field heat assisted magnetic recording with a planar solid immersion lens, Jpn. J. Appl. Phys., vol. 45, no. 2B, pp , C. Mihalcea, K. Pelhos, T. Rausch, C. Peng, W. A. Challener, E. Gage, K. Mountfield, and M. A. Seigler, Fabrication of dielectric optical waveguides on AlTiC sliders for heat assisted magnetic recording, Proc. of SPIE, Vol. 538, Optical Data Storage 24, pp (24). 8 P. Yeh, Optical Waves in Layered Media, John Wiley & Sons, New York, 1988, chapt J.-U. Thiele, K. R. Coffey, M. F. Toney, J. A. Hedstrom, and A. J. Kellock, Temperature dependent magnetic properties of highly chemically ordered Fe55-xNixPt45L1 films, JAP 91, pp (22) 1 T. Rausch, C. D. Mihalcea, K. Pelhos, C. Peng, E. C. Gage, K. Mountfield, M. A. Seigler, and W. A. Challener, Spin stand characterization of dielectric optical waveguides fabricated on AlTiC sliders for heat assisted magnetic recording, Proc. of SPIE, Vol. 538, Optical Data Storage 24, pp (24). 11 L.Yin et al., Surface plasmons at single nanoholes in Au films, Appl. Phys. Lett., vol. 85, no. 3, pp , Jul E. Popov, et al., Surface plasmon excitation on a single subwavelength hole in a metallic sheet, Appl. Opt., vol. 44, pp , (25). 13 Shi and Hesselink, Jap. J. Appl. Phys. vol. 41, R. Grober, S. Bukofsky, and S. Selberg, Application of near-field optics to critical dimension metrology, Appl. Phys. Lett.. vol. 7, pp May T. Matsumoto, Y. Anzai, T. Shintani, K Nakamura, and T. Nishida, Writing 4-nm marks by using a beaked metallic plate near-field optical probe, ISOM/ODS 5, Honolulu, Hawaii, July 14, 25. > FOR CONFERENCE-RELATED PAPERS, REPLACE THIS LINE WITH YOUR SESSION NUMBER, E.G., AB-2 (DOUBLE-CLICK HERE) < 6 seen that once the laser power is high enough to assist the writing at low currents, there is an optimum write current, and further increasing the current degrades the readback signal. It may be that at the optimum operating conditions, the thermal and magnetic profiles in the media are adding to give a better transition, as discussed above in Fig. 5. F. Future HAMR Prospects To achieve a spot size smaller than these diffraction limited spots, a Near-Field Transducer (NFT) using surface plasmon resonance may be employed. Some of the designs that have been proposed so far are circular apertures [11, 12], rectangular apertures [13], C apertures, bow ties [14], and a beaked triangle [15]. The efficiency with which power can be coupled from the NFT to the media needs to be maximized. Also, the NFT must fly closer to the media (<1 nm) compared to the PSIM described above in order to efficiently couple the power in a small spot to the media and it must be able to be integrated with the magnetic field delivery. In addition to being able to produce a smaller optical spot, higher anisotropy media with small grains and a relatively low Tc needs to be developed to support the extremely high areal densities. The media lubricant needs to work at the media Tc and the head needs to be able to deliver this much heat to the media, and all of these need to be achieved with great long term reliability. All of these challenges need to be met in a high yielding, cost effective manner in order for HAMR to be the next data storage technology. III. CONCLUSION The need for an alternative magnetic recording scheme was introduced, along with the HAMR recording concept. Three major challenges of designing a HAMR head were discussed. A fully integrated HAMR head design was introduced and ABS view SEM and optical images were shown. The optical images was taken such that the focused laser spot was visible beneath the poles. SNOM characterization of the ABS was shown for a PSIM only HAMR head where the optical spot FWHM was ~124 nm and for a fully integrated HAMR head with apertures where the optical spot FWHM was ~14 nm. Sidelobes in the intensity profile were apparent for the head without apertures, and they were significantly reduced for the head with apertures. An MFM image of media showed that was not able to be written using Non-HAMR (laser power off), even at very high write currents, but transitions could be written using HAMR (laser power on), even at lower write currents. A cross-track profile was shown for a fully integrated HAMR head where the pole was ~35 nm wide, and the written track was ~2 nm wide, which shows the HAMR effect. A HAMR optimization contour showed that there was an optimum write current and laser power and that simply going to the highest write current and laser power did not lead to the best recording. Lastly, some prospects for advancing HAMR were given and a few key problems to be solved were mentioned. ACKNOWLEDGMENT The authors would like to thank Jay Jayashankar for his chemical mechanical processing, Stanko Brankovic for his electrodeposition processing, Xiaobin Zhu for the MFM work, and Mark Kryder for his leadership and giving us the resources to do this work. REFERENCES [1] R. E. Rottmayer, S. Batra, D. Buechel, W. A. Challener, J. Hohlfeld, Y. Kubota, L. Li, B. Lu, C. Mihalcea, K. Mountfield, K. Pelhos, C. Peng, T. Rausch, M. A. Seigler, D. Weller, and X. Yang, Heat-Assisted Magnetic Recording, IEEE Trans. Magn. Vol. 42, No. 1, (26) [2] M. A. Seigler, T. W. Clinton, M. W. Covington, and C. D. Mihalcea, Data writing with plasmon resonator, US Patent Appl [3] W. A. Challener, C. D. Mihalcea, T. Rausch, Apparatus and method for producing a small spot of optical energy, US Patent 6,795,63 [4] W. Challener, C. Mihalcea, C. Peng, and K. Pelhos, Miniature planar solid immersion mirror with focused spot less than a quarter wavelength, Opt. Exp., vol. 13, no. 18, pp , (25). [5] C. Peng, C. Mihalcea, D. Buechel, W. Challener and E. Gage, Near field optical recording with a planar solid immersion mirror, APL, vol. 87, pp [6] T. Rausch, et al., Near field heat assisted magnetic recording with a planar solid immersion lens, Jpn. J. Appl. Phys., vol. 45, no. 2B, pp , 26. [7] C. Mihalcea, K. Pelhos, T. Rausch, C. Peng, W. A. Challener, E. Gage, K. Mountfield, and M. A. Seigler, Fabrication of dielectric optical waveguides on AlTiC sliders for heat assisted magnetic recording, Proc. of SPIE, Vol. 538, Optical Data Storage 24, pp (24). [8] P. Yeh, Optical Waves in Layered Media, John Wiley & Sons, New York, 1988, chapter 11. [9] J.-U. Thiele, K. R. Coffey, M. F. Toney, J. A. Hedstrom, and A. J. Kellock, Temperature dependent magnetic properties of highly chemically ordered FeNiPt L1 films, JAP 91, pp (22) [1] T. Rausch, C. D. Mihalcea, K. Pelhos, C. Peng, E. C. Gage, K. Mountfield, M. A. Seigler, and W. A. Challener, Spin stand characterization of dielectric optical waveguides fabricated on AlTiC sliders for heat assisted magnetic recording, Proc. of SPIE, Vol. 538, Optical Data Storage 24, pp (24). [11] L.Yin et al., Surface plasmons at single nanoholes in Au films, Appl. Phys. Lett., vol. 85, no. 3, pp , Jul. 24. [12] E. Popov, et al., Surface plasmon excitation on a single subwavelength hole in a metallic sheet, Appl. Opt., vol. 44, pp , (25). [13] Shi and Hesselink, Jap. J. Appl. Phys. vol. 41, 22. [14] R. Grober, S. Bukofsky, and S. Selberg, Application of near-field optics to critical dimension metrology, Appl. Phys. Lett.. vol. 7, pp May [15] T. Matsumoto, Y. Anzai, T. Shintani, K Nakamura, and T. Nishida, Writing 4-nm marks by using a beaked metallic plate near-field optical probe, ISOM/ODS 5, Honolulu, Hawaii, July 14, 25. Michael A. Seigler (M 91) received the B.S. degree in electrical and computer engineering from the Pennsylvania State University in 1992, and M.S. and Ph.D. degrees in electrical and computer engineering from Carnegie Mellon University in 1995 and 1998 respectively. His graduate work included the design, fabrication and characterization of integrated optical devices and near-field optical imaging. He joined Seagate Research in Pittsburgh, Pennsylvania as a Research Staff Member in 1998 and is currently the Research Engineering Manager of the Materials & Device Processing group in Seagate Research.