Heat assisted magnetic recording head having wider heat sink and pole

In one embodiment, a system includes a magnetic head having a write portion having a main pole, a near field transducer comprising a conductive metal film having outer regions extending from an active region, and an optical waveguide for illumination of the near field transducer, wherein the conductive metal film extends in a cross track direction for a width at least 200% greater than a width of the active region of the conductive metal film, wherein a portion of the main pole extends along the conductive metal film in a cross track direction for a width at least 200% greater than the width of the active region of the conductive metal film.

FIELD OF THE INVENTION

The present invention relates to data storage systems, and more particularly, this invention relates to heat assisted recording heads which have a wider heat sink and/or main pole.

BACKGROUND

A magnetic hard disk drive (HDD) includes a rotating magnetic disk, a slider that has read and write heads, a suspension arm above the rotating disk and an actuator arm that swings the suspension arm to place the read and/or write heads over selected circular tracks on the rotating disk. The suspension arm biases the slider into near contact with the surface of the disk, whereby air is swirled by the rotating disk adjacent an air bearing surface (ABS) of the slider, causing the slider to ride on an air bearing a slight distance from the surface of the rotating disk. When the slider rides on the air bearing the write and read heads are employed for writing magnetic impressions to and reading magnetic signal fields from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.

The volume of information processing in the information age is increasing rapidly. In particular, it is desired that HDDs be able to store more information in their limited area and volume. A technical approach to this desire is to increase the capacity by increasing the recording density of the HDD.

The ongoing quest for higher storage bit densities in magnetic media used in disk drives have reduced the size (volume) of data cells to the point where the cell dimensions are limited by the grain size of the magnetic material. Although grain size can be reduced further, there is concern that data stored within the cells is no longer thermally stable, as random thermal fluctuations at ambient temperatures are sufficient to erase data. This state is described as the superparamagnetic limit, which determines the maximum theoretical storage density for a given magnetic media. This limit may be raised by increasing the coercivity of the magnetic media or lowering the temperature. Lowering the temperature is not a practical option when designing hard disk drives for commercial and consumer use. Raising the coercivity is a practical solution, but requires write heads employing higher magnetic moment materials, or techniques such as perpendicular recording (or both).

One additional solution has been proposed, which employs heat to lower the effective coercivity of a localized region on the magnetic media surface and writes data within this heated region. The data state becomes “fixed” upon cooling the media to ambient temperatures. This technique is broadly referred to as “heat assisted (magnetic) recording”, HAMR, or “thermally assisted magnetic recording” TAR or TAMR. It can be applied to both longitudinal or perpendicular recording systems, although the highest density state of the art storage systems are more likely to be perpendicular recording systems. Heating of the media surface has been accomplished by a number of techniques such as focused laser beams or near field optical sources.

Although thermally assisted recording allows for a more precise recording to media, operating temperatures can rise high enough to compromise head functionality if left unmanaged. Peak temperatures in TAR media can reach over 800° C. during normal operation of heating media while writing data thereto, e.g., to reach the media's Curie temperature. Moreover, HAMR heads having inadequate heat sinking capabilities may also reach temperatures of several hundred degrees. Thus, thermal management is an important factor for TAR heads and is one of the gating issues for head reliability. Without thermal management, serious damage to the head and/or magnetic medium may result, such as metal diffusion on the TAR head, thermal degradation, etc.

SUMMARY

In one embodiment, a system includes a magnetic head having a write portion having a main pole, a near field transducer comprising a conductive metal film having outer regions extending from an active region, and an optical waveguide for illumination of the near field transducer, wherein the conductive metal film extends in a cross track direction for a width at least 200% greater than a width of the active region of the conductive metal film, wherein a portion of the main pole extends along the conductive metal film in a cross track direction for a width at least 200% greater than the width of the active region of the conductive metal film.

In another embodiment, a system includes a magnetic head having a write portion having a main pole and a return pole, a near field transducer comprising a conductive metal film having an active region, the active region having a main body and a ridge extending from the main body; and outer regions extending from the active region; an optical waveguide for illumination of the near field transducer, wherein each outer region has a width in a cross track direction that is at least 100% greater than a width of the active region in the cross track direction.

Any of these embodiments may be implemented in a magnetic data storage system such as a disk drive system, which may include a magnetic head, a drive mechanism for passing a magnetic medium (e.g., hard disk) over the magnetic head, and a controller electrically coupled to the magnetic head.

DETAILED DESCRIPTION

The following description discloses several preferred embodiments of disk-based storage systems and/or related systems and methods, as well as operation and/or component parts thereof.

In one general embodiment, a system includes a magnetic head having a write portion having a main pole, a near field transducer comprising a conductive metal film having outer regions extending from an active region, and an optical waveguide for illumination of the near field transducer, wherein the conductive metal film extends in a cross track direction for a width at least 200% greater than a width of the active region of the conductive metal film, wherein a portion of the main pole extends along the conductive metal film in a cross track direction for a width at least 200% greater than the width of the active region of the conductive metal film.

In another general embodiment, a system includes a magnetic head having a write portion having a main pole and a return pole, a near field transducer comprising a conductive metal film having an active region, the active region having a main body and a ridge extending from the main body; and outer regions extending from the active region; an optical waveguide for illumination of the near field transducer, wherein each outer region has a width in a cross track direction that is at least 100% greater than a width of the active region in the cross track direction.

Referring now toFIG. 1, there is shown a disk drive100in accordance with one embodiment of the present invention. As shown inFIG. 1, at least one rotatable magnetic medium (e.g., magnetic disk112) is supported on a spindle114and rotated by a drive mechanism, which may include a disk drive motor118. The magnetic recording on each disk is typically in the form of an annular pattern of concentric data tracks (not shown) on the disk112. Thus, the disk drive motor118preferably passes the magnetic disk112over the magnetic read/write portions121, described immediately below.

At least one slider113is positioned near the disk112, each slider113supporting one or more magnetic read/write portions121, e.g., of a magnetic head according to any of the approaches described and/or suggested herein. As the disk rotates, slider113is moved radially in and out over disk surface122so that portions121may access different tracks of the disk where desired data are recorded and/or to be written. Each slider113is attached to an actuator arm119by means of a suspension115. The suspension115provides a slight spring force which biases slider113against the disk surface122. Each actuator arm119is attached to an actuator127. The actuator127as shown inFIG. 1may be a voice coil motor (VCM). The VCM comprises a coil movable within a fixed magnetic field, the direction and speed of the coil movements being controlled by the motor current signals supplied by controller129.

During operation of the disk storage system, the rotation of disk112generates an air bearing between slider113and disk surface122which exerts an upward force or lift on the slider. The air bearing thus counter-balances the slight spring force of suspension115and supports slider113off and slightly above the disk surface by a small, substantially constant spacing during normal operation. Note that in some embodiments, the slider113may slide along the disk surface122.

The various components of the disk storage system are controlled in operation by control signals generated by controller129, such as access control signals and internal clock signals. Typically, control unit129comprises logic control circuits, storage (e.g., memory), and a microprocessor. In a preferred approach, the control unit129is electrically coupled (e.g., via wire, cable, line, etc.) to the one or more magnetic read/write portions121, for controlling operation thereof. The control unit129generates control signals to control various system operations such as drive motor control signals on line123and head position and seek control signals on line128. The control signals on line128provide the desired current profiles to optimally move and position slider113to the desired data track on disk112. Read and write signals are communicated to and from read/write portions121by way of recording channel125.

An interface may also be provided for communication between the disk drive and a host (integral or external) to send and receive the data and for controlling the operation of the disk drive and communicating the status of the disk drive to the host, all as will be understood by those of skill in the art.

In a typical head, an inductive write portion includes a coil layer embedded in one or more insulation layers (insulation stack), the insulation stack being located between first and second pole piece layers. A gap is formed between the first and second pole piece layers by a gap layer at an air bearing surface (ABS) of the write portion. The pole piece layers may be connected at a back gap. Currents are conducted through the coil layer, which produce magnetic fields in the pole pieces. The magnetic fields fringe across the gap at the ABS for the purpose of writing bits of magnetic field information in tracks on moving media, such as in circular tracks on a rotating magnetic disk.

The second pole piece layer has a pole tip portion which extends from the ABS to a flare point and a yoke portion which extends from the flare point to the back gap. The flare point is where the second pole piece begins to widen (flare) to form the yoke. The placement of the flare point directly affects the magnitude of the magnetic field produced to write information on the recording medium.

FIG. 2Aillustrates, schematically, a conventional recording medium such as used with magnetic disc recording systems, such as that shown inFIG. 1. This medium is utilized for recording magnetic impulses in or parallel to the plane of the medium itself. The recording medium, a recording disc in this instance, comprises basically a supporting substrate200of a suitable non-magnetic material such as glass, with an overlying coating202of a suitable and conventional magnetic layer.

FIG. 2Bshows the operative relationship between a conventional recording/playback head204, which may preferably be a thin film head, and a conventional recording medium, such as that ofFIG. 2A.

FIG. 2Cillustrates, schematically, the orientation of magnetic impulses substantially perpendicular to the surface of a recording medium as used with magnetic disc recording systems, such as that shown inFIG. 1. For such perpendicular recording the medium typically includes an under layer212of a material having a high magnetic permeability. This under layer212is then provided with an overlying coating214of magnetic material preferably having a high coercivity relative to the under layer212.

FIG. 2Dillustrates the operative relationship between a perpendicular head218and a recording medium. The recording medium illustrated inFIG. 2Dincludes both the high permeability under layer212and the overlying coating214of magnetic material described with respect toFIG. 2Cabove. However, both of these layers212and214are shown applied to a suitable substrate216. Typically there is also an additional layer (not shown) called an “exchange-break” layer or “interlayer” between layers212and214.

In this structure, the magnetic lines of flux extending between the poles of the perpendicular head218loop into and out of the overlying coating214of the recording medium with the high permeability under layer212of the recording medium causing the lines of flux to pass through the overlying coating214in a direction generally perpendicular to the surface of the medium to record information in the overlying coating214of magnetic material preferably having a high coercivity relative to the under layer212in the form of magnetic impulses having their axes of magnetization substantially perpendicular to the surface of the medium. The flux is channeled by the soft underlying coating212back to the return layer (P1) of the head218.

FIG. 2Eillustrates a similar structure in which the substrate216carries the layers212and214on each of its two opposed sides, with suitable recording heads218positioned adjacent the outer surface of the magnetic coating214on each side of the medium, allowing for recording on each side of the medium.

FIG. 3Ais a cross-sectional view of a perpendicular magnetic head. InFIG. 3A, helical coils310and312are used to create magnetic flux in the stitch pole308, which then delivers that flux to the main pole306. Coils310indicate coils extending out from the page, while coils312indicate coils extending into the page. Stitch pole308may be recessed from the ABS318. Insulation316surrounds the coils and may provide support for some of the elements. The direction of the media travel, as indicated by the arrow to the right of the structure, moves the media past the lower return pole314first, then past the stitch pole308, main pole306, trailing shield304which may be connected to the wrap around shield (not shown), and finally past the upper return pole302. Each of these components may have a portion in contact with the ABS318. The ABS318is indicated across the right side of the structure.

Perpendicular writing is achieved by forcing flux through the stitch pole308into the main pole306and then to the surface of the disk positioned towards the ABS318.

FIG. 3Billustrates a piggyback magnetic head having similar features to the head ofFIG. 3A. Two shields304,314flank the stitch pole308and main pole306. Also sensor shields322,324are shown. The sensor326is typically positioned between the sensor shields322,324.

FIG. 4Ais a schematic diagram of one embodiment which uses looped coils410, sometimes referred to as a pancake configuration, to provide flux to the stitch pole408. The stitch pole then provides this flux to the main pole406. In this orientation, the lower return pole is optional. Insulation416surrounds the coils410, and may provide support for the stitch pole408and main pole406. The stitch pole may be recessed from the ABS418. The direction of the media travel, as indicated by the arrow to the right of the structure, moves the media past the stitch pole408, main pole406, trailing shield404which may be connected to the wrap around shield (not shown), and finally past the upper return pole402(all of which may or may not have a portion in contact with the ABS418). The ABS418is indicated across the right side of the structure. The trailing shield404may be in contact with the main pole406in some embodiments.

FIG. 4Billustrates another type of piggyback magnetic head having similar features to the head ofFIG. 4Aincluding a looped coil410, which wraps around to form a pancake coil. Also, sensor shields422,424are shown. The sensor426is typically positioned between the sensor shields422,424.

InFIGS. 3B and 4B, an optional heater is shown near the non-ABS side of the magnetic head. A heater (Heater) may also be included in the magnetic heads shown inFIGS. 3A and 4A. The position of this heater may vary based on design parameters such as where the protrusion is desired, coefficients of thermal expansion of the surrounding layers, etc.

Magnetic heads, such as those listed above, may be used in conjunction with TAR. However, as described above, peak temperature in TAR heads can reach over 800° C. during normal operation. Thus, thermal management is an important factor for TAR heads. Without thermal management, damage to the head and/or magnetic medium may result, such as metal diffusion on the TAR head.

To alleviate this problem, various embodiments described and/or suggested herein preferably provide an improved TAR head heat sink design, which reduces head peak temperature. Preferably, the different approaches described and/or suggested herein may reduce head peak temperature by up to about 10%, more preferably up to about 20%, still more preferably up to about 25%, compared to an otherwise identical head without the novel features discussed herein, as will be discussed in further detail below.

Now referring toFIG. 5A, a partial cross section view of a system500having a thin film perpendicular write head design incorporating an integrated aperture near field optical source (e.g., for TAR operation) is shown according to one embodiment. Of course, this embodiment may be used in conjunction with any structures and systems described in any of the other figures. In order to simplify and clarify the structures presented, spacing layers, insulating layers, and write coil layers may be omitted from the subsequent figures and descriptions.

With continued reference toFIG. 5A, the write head has a lower return pole layer502, back-gap layer(s)504, upper return pole layer506, and upper pole tip layer508. In one approach, the lower return pole layer502may also have a lower pole tip (not shown) at the ABS. Layer510is an optical waveguide core, which may be used while conducting TAR, e.g., to heat a medium (not shown) at the ABS when the system500is writing thereto. According to a preferred approach, the optical waveguide core is surrounded by cladding layers512. Moreover, layers510and512may extend through at least a portion of back-gap layer(s)504. The components inside of Circle5B are shown in an expanded view inFIG. 5B, as discussed in further detail below.

Layer510may be comprised of a suitable light transmitting material, as would be known by one of reasonable skill in the relevant art. Exemplary materials preferably include Ta2O5, and/or TiO2. As shown, the core layer510has approximately uniform cross section along its length. As well known in the art, the optical waveguide can have a number of other possible designs including a planar solid immersion mirror or planar solid immersion lens which have a non-uniform core cross section along the waveguide's length.

In various approaches, coil layers (not shown) and various insulating and spacer layers (not shown) might reside in the cavity bounded by the ABS, back-gap(s)504, lower return pole502, and/or upper bounding layers506,508, and512as would be recognized by those of skill in the art. Layers502,504,506, and508may be comprised of a suitable magnetic alloy or material, as would be known by one of reasonable skill in the relevant art. Exemplary materials include Co, Ni, and/or Fe and combinations thereof.

As described above,FIG. 5Bis a partial cross section expanded view of detail5B inFIG. 5A, in accordance with one embodiment. Pole lip516is magnetically coupled to upper pole tip layer508, and to optional magnetic step layer514. Aperture518(also known as a ridge aperture), surrounding metal layer520, and pole lip516comprise the near field aperture optical source (or near field transducer), which is supplied optical energy via optical waveguide core510. Pole lip516and optional magnetic step layer514may be comprised of a suitable magnetic alloy, such as Co, Fe, Ni, and/or combinations thereof. Metal layer520may be comprised of Cu, Au, Ag, and/or alloys thereof, etc.

With continued reference toFIG. 5B, cladding layer512thickness may be nominally about 200 nm, but may be thicker or thinner depending on the dimensions of other layers in the structure. Optional magnetic step layer514may have a nominal thickness (the dimension between layers508and510) of about 150 nm, and a nominal depth (as measured from layer516to layer512) of about 180 nm. Pole lip516may have a nominal depth (as measured from the ABS) approximately equal to that of layer520, with the value being determined by the performance and properties of the near field optical source (see examples below). The thickness of the pole lip516can vary from about 150 nm (with the optional magnetic step layer514) to about 1 micron, preferably between about 250 nm and about 350 nm. The thickness of optical waveguide core layer510may be nominally between about 200 nm and about 400 nm, sufficient to cover the thickness of the aperture518.

As described above, thermal management is an important factor for TAR heads, as high operating temperatures in TAR heads can lead to serious damage thereto. Thus, various embodiments described and/or suggested herein preferably include an improved heat sink design which may reduce the head peak temperature of TAR heads. As a result, according to various approaches, the NFT peak temperature can effectively be reduced, thereby improving head reliability significantly. Moreover, approaches described and/or suggested herein may also allow for a narrower main pole lip in addition to a wider step, thereby improving performance of the system.

FIGS. 6A-7Bdepict a system600for reducing TAR head peak operating temperatures, in accordance with one embodiment. As an option, the present system600may be implemented in conjunction with features from any other embodiment listed herein, such as those described with reference to the other FIGS. Of course, however, such system600and others presented herein may be used in various applications and/or in permutations which may or may not be specifically described in the illustrative embodiments listed herein. Further, the system600presented herein may be used in any desired environment. ThusFIGS. 6A-7B(and the other FIGS.) should be deemed to include any and all possible permutations.

Referring now toFIGS. 6A-7B, the system600includes a magnetic head602. As illustrated, the magnetic head602includes a write portion having a main pole606and a near field transducer. According to various approaches, the near field transducer ofFIGS. 6A-7Bmay include the same or similar approaches as516,518,520ofFIG. 5. Moreover, although not shown, the magnetic head602may also include a return pole (e.g., seeFIGS. 3A-4B).

With continued reference toFIGS. 6A-7B, the near field transducer includes an electrically conductive metal film608having outer regions610extending from an active region612. The active region612of the conductive metal film608is generally defined as the portion thereof that is illuminated by light from the waveguide616as will soon become apparent, but is not limited thereto. According to various approaches, the conductive metal film608may include ruthenium, gold, rhodium, chrome, gold-copper alloy, etc., or any other conductive material suitable for use as a near field transducer, which would be apparent to one skilled in the art upon reading the present description. In a preferred approach, the conductive metal film608is nonmagnetic, e.g., to prevent from affecting the magnetic recording of the head602, but is not limited thereto.

The system600additionally includes an optical waveguide616and cladding layers615for illumination of the near field transducer, e.g., to enable TAR performance. According to different approaches, the optical waveguide616may include any of the materials and/or configurations described above with reference to layer510ofFIG. 5. Moreover, cladding layers615may incorporate any of the approaches described above with reference to512ofFIGS. 5A-5B.

Referring again toFIGS. 6A-7B, the thickness t of the conductive metal film608, in the in-track direction Y, may have a value in a range from less than the width of the waveguide in the same direction, to greater than the width of the waveguide and cladding. Thus, in various approaches, the waveguide616, cladding layers615and/or conductive metal film608may have a thickness in the in-track direction Y from about 0.35 μm to about 0.65 μm, but may be higher or lower depending on the desired embodiment.

According to one approach, the light guiding core of the optical waveguide616may be directly coupled to the near field transducer (e.g., having physical contact therebetween). However, in another approach, the light guiding core of the optical waveguide616may be spaced from the near field transducer in a height direction, e.g., perpendicular to the media facing surface thereof, by a spacer614. According to different approaches, the optical waveguide may be spaced from the near field transducer by greater than 0 nanometers and less than about 100 nanometers, more preferably greater than 0 nanometers and less than about 20 nanometers, but may be higher depending on the desired embodiment. According to one approach, which is in no way intended to limit the invention, the dimensions of the spacer614may depend, at least in part, on the design of the active region of the conductive metal film608.

According to some embodiments, to effectively implement TAR, it may be beneficial to confine the heat applied to the medium to about a single data track. Thus, according to one approach a ridge may be used to focus heating to a single track. In a preferred approach, the active region612of the conductive metal film608may have a main body and a ridge extending from the main body. Thus, according to one approach, the near field transducer may include a ridge622extending from the conductive metal film608in the active region612thereof. Depending on the desired embodiment, the ridge622may be formed by incorporating different designs. In one approach, the conductive metal film may have a C aperture formed therein. However, according to another approach, the conductive metal film may have an E shape.

According to various approaches, the size and/or shape of the ridge may be tunable based on the desired performance thereof. Moreover, the conductive metal film designs incorporating a ridge as mentioned above, in addition to other exemplary embodiments thereof, are described in further detail in U.S. patent application Ser. No. 13/438,811, which is herein incorporated by reference.

Referring still toFIGS. 6A-7B, the conductive metal film608extends in a cross track direction X for a total width W1. Preferably the width W1extends much wider than the width W2of the active region612such that the heat generated therein is directed away e.g., towards the outer regions, and preferably absorbed by the main pole606therealong. Thus, according to one approach, the total width W1of the conductive metal film608may extend at least 200% greater than a width W2of the active region612of the conductive metal film608, more preferably greater than 400% thereof, even more preferably greater than 500% thereof. According to another approach, each outer region610may have a width in a cross track direction that is at least 100% greater than the width W2of the active region612in the cross track direction X, preferably greater than 200% thereof, more preferably greater than 250% thereof.

Preferably, the conductive metal film608may have a total width W1from about 1 μm to about 10 μm, preferably about 1.5 μm to about 5 μm. In one illustrative embodiment, the total width W1may be about 3 μm.

FIGS. 6C and 6Ddepict partial cross sectional ABS views of the head ofFIG. 6A, and an alternate embodiment. As shown, the active portion612and the outer regions610of the conductive metal film may have the same composition, as shown inFIG. 6C, or may have different compositions as shown inFIG. 6D. In such case, the outer regions610are preferably formed of a nonmagnetic metal (or other material) having a high thermal conductivity, e.g., comparable to the thermal conductivity of the pole606. Illustrative materials for the outer regions include chromium, aluminum, ruthenium, rhodium, gold, copper, etc.

FIG. 8depicts a graphical representation formed by the inventors through modeling of the head design illustrated inFIGS. 6A-6B. The graph800illustrates the relationship between peak operating temperatures corresponding to different widths of the main pole in a cross track direction at a media-facing surface (X direction in FIG.6A). Moreover, as noted on the graph800, the lip thickness in the Y direction of the head used in the testing was 280 nm. The inventors found that by increasing the width of the main pole (e.g., heat sink) as described in the various approaches herein, the peak temperature of the TAR head desirably decreases. After testing a wide range of widths for the main pole, the inventors discovered that the peak temperature drops very little for main pole widths larger than about 3 μm. Thus, without wishing to be bound by any theory, the inventors believe the optimal width of the main pole to be about 3 μm, for the design tested.

Referring again toFIGS. 6A-7B, the width W1of the conductive metal film608is preferably about the same as the width of the portion of the main pole606at a media-facing surface (e.g., an air bearing surface (ABS)) of the portion of the main pole606. Moreover, in a similar approach the distance between outer ends of the outer regions610may be about as wide as a width of a portion of the main pole606at a media-facing surface of the portion of the main pole606. Thus, the wider main pole606may absorb a maximized amount of the heat carried by the conductive metal film608along the width of W1.

In other embodiments, the width W1of the conductive metal film608may be greater than, or less than, the width of the portion of the main pole606at the media-facing surface.

In a further approach, the portion of the main pole606(e.g., at a media facing surface) may extend along the conductive metal film608in a cross track direction X for a width at least 200% greater than the width W2of the active region612of the conductive metal film608.

According to another approach, the width of the portion of the main pole606is preferably about the same as or greater than a track width. According to the present description, the track width can be generally defined as an average width of a track of data as written by the head to a continuous (as opposed to patterned) magnetic medium in the cross track direction X, prior to any shingling.

Looking now toFIGS. 7A-7B, according to one approach, the height h1of at least one part of the outer regions610may be greater than a height h2of the active region612. As illustrated, the heights h1, h2are measured in a direction perpendicular to a media facing side of the conductive metal film608.

According to one approach, the height of at least a portion of the outer regions may increase therealong away from the active region. For example, as illustrated inFIGS. 7A-7B, the height of the conductive metal film increases away from the active region, thereby creating a tapered (e.g., flared) shape. Furthermore, according to various other approaches, the height of the conductive metal film608may increase in a stepped fashion, a curved shape, etc., depending on the desired embodiment.

However, in yet another approach, the height of the conductive metal film608may be about uniform from the active region612spanning through the outer regions610(e.g., seeFIG. 6B). According to different instances, the height of a uniform conductive metal film608from the active region612spanning through the outer regions610may be from about 30 nm to about 200 nm, but may be higher or lower depending on the desired embodiment. According to various approaches, the height of the conductive metal film608may vary depending on the materials used therein, design of the system, fabrication methods, etc.

The increased height of the outer regions610preferably allows for more area for heat transfer between the conductive metal film608and the main pole606, thereby further increasing the amount of heat transferred therebetween and absorbed by the main pole606. The inventors have discovered through further modeling that the peak operating temperatures may be reduced by 31° C., in the examples modeled, by incorporating a conductive metal film having tapered outer regions, relative to a model where the conductive metal film has an about uniform height. Modeling also showed that the peak operating temperatures may be reduced by 98° C., in the examples modeled, by incorporating a conductive metal film having tapered outer regions, relative to a model where the heat sink is not extended in the cross track direction. This reduction in peak operating temperature desirably elongates TAR head life expectancies, by at least reducing thermal degradation thereof.

With continued reference toFIGS. 6A-7B, the main pole606of the write portion may have a step618extending towards the conductive metal film608of the near field transducer in an in-track direction Y. According to various approaches, the step618may have a thickness in the in-track direction Y from about 0.10 to about 0.25, but may be higher or lower, depending on the desired embodiment.

Moreover, according to a preferred approach, the step618is shown inFIGS. 6A and 7Aextending from the portion of the main pole606, e.g., at about the media-facing surface. Thus, the outer regions610of the conductive metal film608preferably extend along the step618as illustrated. The step618may be part of the main pole606, or a layer formed separately therefrom.

Although in a preferred approach the conductive metal film may be in direct contact with the main pole as inFIG. 7A, a secondary heat sink layer620may extend from the main pole606of the write portion, towards the conductive metal film608, e.g., spanning to the outer regions610. SeeFIG. 6A. Thus, according to one approach, if the main pole606has a step618, the secondary heat sink layer620may be positioned between the conductive metal film608and the step618, and extend laterally from the main pole lip623, shown inFIG. 6C. In a preferred approach, the secondary heat sink layer620may have about the same height(s) (e.g., shape or profile) as the conductive metal film608. It follows that, according to one approach, if the height h1of the outer regions610is greater than the height h2of the active region612, the height of portions of the secondary heat sink layer620extending along the outer regions610is preferably greater than a height of the secondary heat sink layer620adjacent the active region612as well; where as described above, the heights are measured in a direction perpendicular to a media facing side of the conductive metal film.

In a preferred approach, the height of the secondary heat sink layer620may be about the same as the height of the conductive metal film608extending therealong. According to one approach, the maximum height of the outer regions of the conductive metal film may be as high as the lip623, and preferably have a height that is equal to the height of the lip ±25% of a height h of the lip (i.e., 75% to 125% of the height of the lip623, seeFIG. 6C), but could be higher or lower depending on the desired embodiment. Moreover, according to another approach, the maximum height of the portions of the secondary heat sink layer620extending along the outer regions may be as high as the step, and preferably have a height that is equal to the height of the step ±25% of a height of the step (i.e., 75% to 125% of the height of the step), but could be higher or lower depending on the desired embodiment. Thus, according to an illustrative approach, which is in no way intended to limit the invention, the outer regions of the conductive metal layer may be about the same height as the lip623, secondary heat sink layer620and/or the step extending along the outer regions thereof.

Furthermore, according to different approaches, the lip620and/or secondary heat sink layer620may have a thickness in the in-track direction Y from about 0.16 to about 0.175, but may be higher or lower depending on the desired embodiment.

Illustrative materials from which the secondary heat sink layer620may be formed include nonmagnetic metals (or other material) having a high thermal conductivity, e.g., comparable to the thermal conductivity of the pole606. Illustrative materials for the outer regions include chromium, aluminum, ruthenium, rhodium, gold, copper, etc.

According to an exemplary approach which is in no way intended to limit the invention, the outer regions610may be formed as a continuous layer with the active region612, e.g., the outer regions610may be part of the conductive metal film608. However, it should be noted that the conductive metal film608may be formed using various layers, and may not necessarily be a unitarily-formed film. Thus, according to different approaches, the active region612and outer regions610may be constructed of the same or different materials, and/or in a separate manufacturing step depending on the desired embodiment. Moreover, according to an exemplary approach, which is in no way intended to limit the invention, the outer regions610and parts of the active region612of the conductive metal film608may be formed in a single step. However, in other approaches, the outer regions610may be formed in a separate step, and optionally of different material than a main body of the active region612.

As described in the various approaches above, the large mass of the main pole acts as an effective thermal conductor for the magnetic head. This significant reduction in the peak operating temperature desirably lengthens the expected life of the embodiments described and/or suggested herein from that of conventional products, thereby favorably reducing system upkeep and operating costs.

It should be noted that methodology presented herein for at least some of the various embodiments may be implemented, in whole or in part, in computer hardware, software, by hand, using specialty equipment, etc. and combinations thereof.

Moreover, any of the structures and/or steps may be implemented using known materials and/or techniques, as would become apparent to one skilled in the art upon reading the present specification.