Short yoke length writer having assist coils

A magnetic apparatus has a media-facing surface (MFS), a pole, a top shield, a back gap and coil(s). The pole includes a yoke extension, a yoke between the yoke extension and the MFS, and a pole tip between the yoke and the MFS. The write gap is between the top shield and the pole tip. The back gap is recessed from the ABS and magnetically and physically connects the top shield to the yoke. The coil(s) energize the pole and have multiple turns. Part of a first turn is between the yoke and the top shield. Part of a second turn is recessed from the MFS and aligned with part of the yoke extension. Part of the first turn is between the part of the second turn and the MFS. The back gap is between part of the first turn and part of the second turn.

BACKGROUND

FIG. 1depicts a side view of a conventional magnetic recording apparatus10. The magnetic recording apparatus10may be a perpendicular magnetic recording (PMR) apparatus. The conventional magnetic apparatus10includes a read apparatus12and a write apparatus20. The conventional read apparatus12includes shields14and18and sensor16. The read sensor16is typically a giant magnetoresistive (GMR) sensor or tunneling magnetoresistive (TMR) sensor. The write apparatus20includes a first or return pole22, coils24and32, back gap, auxiliary poles28, main pole30and shield34. Although not shown, the pole30may have leading and/or trailing edge bevels. In such cases, the pole30is shortest in the down track direction at the ABS.

Although the conventional magnetic recording head10functions, there are drawbacks. In particular, the conventional magnetic recording head10may not perform sufficiently at higher recording densities and higher recording speeds. For example, as recording areal density approaches 1 Tb/in2and above, the data recording rate may exceed 2.2 Gb/s. High data rates require rapid changes in the magnetic flux provided by the pole22. The pole22may not have sufficiently low rise time for the magnetic flux. The write field provided by the main pole30may also be desired to meet particular standards, such as magnitude and gradient. The pole22may not be capable of meeting these standards. Accordingly, what is needed is a system and method for improving the performance of a magnetic recording head, particularly at higher areal densities.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the various embodiments disclosed are applicable to a variety of data storage devices such as magnetic recording disk drives, solid-state hybrid disk drives, networked storage systems etc., for the sake of illustration the description below uses disk drives as examples.

FIG. 2depicts a side view of an exemplary embodiment of a portion of a disk drive100including a write apparatus120.FIG. 3depicts a close-up side view of an exemplary embodiment of a magnetic disk drive100/write apparatus120. For clarity,FIGS. 2-3are not to scale. Referring toFIGS. 2-3, for simplicity not all portions of the disk drive100are shown. In addition, although the disk drive100is depicted in the context of particular components other and/or different components may be used. For example, circuitry used to drive and control various portions of the disk drive100is not shown. For simplicity, only single components102,110,120and their components are shown. However, multiples of each components102,110,120and/or and their sub-components, might be used. The disk drive100may be a PMR disk drive. However, in other embodiments, the disk drive100may be configured for other types of magnetic recording.

The disk drive100includes media102, a slider110and the write apparatus120. Additional and/or different components may be included in the disk drive100. Although not shown, the slider110and thus the write apparatus120are generally attached to a suspension (not shown). The write apparatus120is fabricated on the slider110and includes a media-facing surface (MFS) proximate to the media102during use. In the embodiment shown, the MFS is an air-bearing surface (ABS). In general, the disk drive100includes a write apparatus120and a read apparatus. However, for clarity, only the write apparatus120is shown.

The write apparatus120includes a pole130, a back gap140, a top shield142/144, write gap146and coil(s)150. In other embodiments, different and/or additional components may be used in the write apparatus120. For example, the write apparatus120might include a return pole.

The pole130includes a pole tip132, a yoke134and a yoke extension136. The separate portions132,134and136of the pole130are delineated by dashed lines. The pole tip132is shown as occupying a portion of the ABS. However, in other embodiments, the pole tip132might be recessed from the ABS. The pole tip132is between the yoke134and the ABS. Similarly, the yoke134is between the yoke extension136and the ABS. The write gap146separates the pole tip132from a portion144of the top shield142/144. The back gap140is recessed from the ABS. The back gap140magnetically and physically connects a portion142of the top shield142/144to the yoke134of the pole130. In some embodiments, the edge of the back gap140furthest from the ABS defines the back edge of the yoke134. The yoke extension136is the portion of the pole130that extends beyond the back gap140in the yoke direction. The yoke length, YL, of the pole130, defined herein as the distance from the ABS to the front of the back gap140, is reduced. In some embodiments, the yoke length is not more than three micrometers. In some such embodiments, the yoke length may be two micrometers or less.

The coil(s)150are used to energize the pole130for writing and include turns152,154,156and158. In other embodiments, another number of turns may be used. For example, more turns recessed from the ABS in a manner analogous to the turns154and158may be used. Although termed separate turns, the turns152,154,156and158may be connected such that fewer turns are present. For example, the coil(s)150may be a helical coil. In such a case, the turns152and156may be part of the same turn. The turns154and158may be then part of the same turn. Similarly, if the coil(s)150are spiral coil(s), then the turns152and154may be part of the same turn. The turns156and158may thus be part of the same turn. Thus, as used herein, a “turn” of a coil may be the portion of the turn depicted in the drawing. In addition, although not shown, it is possible for the write apparatus120to have coil turns that are far from the ABS and not depicted in the drawings. Finally, in some embodiments, the turns156and158might be omitted.

One turn152is between the yoke134and a portion142of the top shield142/144. Another turn154is recessed from the ABS such that the turn154is aligned with part of the yoke extension136. Although shown as having its back edge aligned with the back edge of the yoke extension136, the turn154might be closer to the ABS. However, the back gap140is between the turns152and154. In some embodiments, the turn154is recessed from the ABS by at least two micrometers and not more than eight micrometers. In some embodiments, the turn154is recessed from the ABS by at least three micrometers. In addition, the turn154is separated from the back gap140by length RL. RL may be at least 0.25 μm, which allows the turn154to be electrically insulated from the back gap140. In some embodiments, however, RL is significantly larger than 0.25 μm. In the embodiment shown, the turns152and154have the same cross-sectional area and shape. In other embodiments, the cross-sectional areas and/or shapes may differ.

As can be seen fromFIG. 3, the turns156and158may be considered analogous to the turns152and154, respectively. Thus, the turn158is recessed further from the ABS and aligned with the yoke extension136. The turn156is aligned with the yoke134. In the embodiment shown, the turns156and158have the same cross-sectional area and shape. In other embodiments, the cross-sectional areas and/or shapes may differ. In addition, the turns152and156are shown as having different cross-sectional area(s) than the turns156and158. However, in other embodiments, the cross-sectional area(s) may be the same. Alternatively, the cross-sectional areas of the turns156and158may be smaller than that of the turns152and154.

The turns152and156are closer to the ABS than the back edge of the back gap140. Thus, the turns152and156may be considered primary turns while the turns154and158may be considered assist turns. The assist turns154and158provide additional current that aids (or assists) the turns152and156in energizing the pole130. For example, the turns152and158may carry current in one direction (e.g. out of the plane of the page inFIG. 3) while the turns154and156carry current in the opposite direction. In other embodiments, the turns152and156may carry current in one direction while the turns154and158carry current in the opposite direction. Similarly, the turns152and154may carry current in one direction while the turns156and158carry current in the opposite direction. Other configurations for carrying current are possible.

In operation, current is driven through the turns152,154,156and158of the coil(s)150to energize the pole130. In some embodiments, the current carried by the turns152,154,156and158is increased over that which might be used in the coils24and32of the conventional write apparatus10. The current through the turns152,154,156and158may be increased such that the magnitude of the field produced by the pole130is analogous to that produced by the conventional pole30. For example, the150coil may carry a current that is 150% of the current carried by the conventional coils24and32. However, other values of the current are possible.

The magnetic disk drive100may exhibit improved performance. Because of the configuration of the turns152,154,156and158of the coil150, the yoke length may be reduced. For example, in some embodiments, the yoke length for the main pole130may be not more than three micrometers. In some such embodiments, the yoke length may be not more than two micrometers. The response time of the pole130may thus be reduced. Data may be written at a higher rate. Further, because of the presence of the assist turns154and158, the coil(s)150may include greater than one turn. Thus, more current may be driven in proximity to the pole130. Therefore, the coil(s)150may better energize the pole130. In particular, the pole130may be configured for a single turn152/156near the ABS, but include additional, assist turn(s)154/158. As a result, a higher magnetic field may be generated in the main pole130for the same write current driven through the coil(s)150. Thus, performance of the disk drive100may be improved.

FIG. 4depicts a side view of an exemplary embodiment of a magnetic disk drive100′. More specifically, a portion of the apparatus120′ is depicted. For simplicity, only a portion of the magnetic recording apparatus120′ is shown.FIG. 4is not to scale for clarity. The magnetic recording disk drive100′ is analogous to the magnetic disk drive100. Consequently, analogous components have similar labels. The write apparatus120′ thus includes a slider (not shown), a pole130, a back gap140, a top shield142/144, write gap146and coil(s)150′ analogous to the pole130, back gap140, top shield142/144, write gap146and coil(s)150, respectively, depicted inFIGS. 2-3.

The pole130includes a pole tip132, a yoke134and a yoke extension136and which are analogous to those described inFIG. 2. The yoke length, YL, of the pole130is reduced. In some embodiments, the yoke length is not more than three micrometers. In some such embodiments, the yoke length may be two micrometers or less. The coil(s)150′ are used to energize the pole130for writing and include turns152,154,156and158. The coil(s)150′ may be spiral or helical coils, as mentioned above. Turns154and158are still assist turns that are recessed from the ABS. One turn152is between the yoke134and a portion142of the top shield142/144. The turn154further from the ABS. Thus, the turn154is a distance RL′ from the back gap140. The back gap140remains between the turns152and154. The turn154is recessed from the ABS by a distance in the range of distances described above. As can be seen fromFIG. 4, the turns156and158may be considered analogous to the turns152and154, respectively. The turn158, though recessed from the ABS and aligned with the yoke extension136, is closer to the ABS than inFIGS. 2-3. Thus, the back edge of the turn158is not substantially the same distance from the ABS as is the back edge of the yoke extension136.

The magnetic write apparatus120′ also includes a return pole170. The return pole170includes a front gap connection174, a back gap connection172and a central region176. The front gap connection174has a portion at the ABS that may act as a leading shield. The back gap connection172that connects the return pole170to the yoke134and, in the embodiment shown, the yoke extension136of the pole130. Thus, in the embodiment shown, the back gap connection172is recessed further from the ABS in the yoke direction than the back gap140. However, the back gap connection172may be a different distance from the ABS. In some embodiments, the front gap connection174and/or the back gap connection172might be omitted.

The magnetic write apparatus120′ may share the benefits of the magnetic write apparatus120. Because of the configuration of the turns152,154,156and158of the coil150′, the yoke length may be reduced. For example, in some embodiments, the yoke length for the main pole130may be not more than three micrometers. In some such embodiments, the yoke length may be not more than two micrometers. The response time of the pole130may be reduced and data written at a higher rate. Because of the use of the assist turns154and158, the coil(s)150′ may include more than one turn close to the pole130despite the reduced yoke length. As a result, a higher magnetic field may be generated in the main pole130for the same write current driven through the coil(s)150′. Thus, performance of the disk drive100′ may be improved. Further, use of the return pole170including the front gap connection174and the back gap connection172may improve the wide area track erasure (WATER) for the write apparatus120′. The return pole170may aid in shielding other tracks from the (possibly higher) current driven through the coils150′. Thus, the improved data rate may be attained without adversely affecting WATER.

FIG. 5depicts a side view of an exemplary embodiment of a magnetic disk drive200. More specifically, a portion of a write apparatus220is depicted. For simplicity, only a portion of the magnetic recording apparatus220is shown.FIG. 5is not to scale for clarity. The magnetic recording disk drive200is analogous to the magnetic disk drive100and100′. Consequently, analogous components have similar labels. The write apparatus220thus includes a slider (not shown), a pole230, a back gap240, a top shield242/244, write gap246, coil(s)250and return pole270analogous to the pole130, back gap140, top shield142/144, write gap146, coil(s)150/150′ and return pole170, respectively.

The pole230includes a pole tip232, a yoke234and a yoke extension236which are delineated by dashed lines and analogous to those described inFIGS. 2-4. The yoke length, YL, of the pole230is reduced. In some embodiments, the yoke length is not more than three micrometers. In some such embodiments, the yoke length may be two micrometers or less. The coil(s)250are used to energize the pole230for writing and include turns252,254,256and258. The coil(s)250may be spiral or helical coils, as mentioned above. Turns254and258are assist turns that are recessed from the ABS. One turn252is between the yoke234and a portion242of the top shield242/244. The turn254is further from the ABS. Thus, the turn254is a distance RL″ from the back gap240. Although a portion of the turn254is aligned with the yoke extension236, another portion of the turn254further from the ABS than the yoke extension236. The back gap240remains between the turns252and254. The turns256and258are analogous to the turns252and254, respectively. The turn258, though recessed from the ABS and partially aligned with the yoke extension236, the back edge of the turn258is further from the ABS than the back edge of the yoke extension236. The magnetic write apparatus220also includes a return pole270having a front gap connection274, a back gap connection272and a central region276. In another embodiment, the return pole270might be omitted. Also depicted inFIG. 5is one configuration in which current may be driven through the turns252,254,256and258.

The magnetic write apparatus220may share the benefits of the magnetic write apparatuses120and120′. Because of the configuration of the turns252,254,256and258, the yoke length may be reduced in a manner analogous to that described above. The response time of the pole230may be reduced and data written at a higher rate. Use of the assist turns254and258, more current can be driven close to the pole230despite the reduced yoke length. As a result, a higher magnetic field may be generated in the main pole230for the same write current driven through the coil(s)250. Further, the use of the return pole270having front gap connection274and the back gap connection272may improve the WATER for the write apparatus220. Thus, the improved data rate and field may be attained without adversely affecting WATER.

FIG. 6depicts a side view of an exemplary embodiment of a magnetic disk drive200′. More specifically, a portion of a write apparatus220′ is depicted. For simplicity, only a portion of the magnetic recording apparatus220′ is shown.FIG. 6is not to scale for clarity. The magnetic recording disk drive200′ is analogous to the magnetic disk drive100,100′ and200. Consequently, analogous components have similar labels. The write apparatus220′ thus includes a slider (not shown), a pole230, a back gap240, a top shield242/244, write gap246, coil(s)250′ and return pole270analogous to the pole130/230, back gap140/240, top shield142/144/242/244, write gap146/246, coil(s)150/150′/250and return pole270, respectively.

The pole230includes a pole tip232, a yoke234and a yoke extension236which are delineated by dashed lines and analogous to those described inFIGS. 2-4. The yoke length, YL, of the pole230is reduced. In some embodiments, the yoke length is not more than three micrometers. In some such embodiments, the yoke length may be two micrometers or less. The coil(s)250′ are used to energize the pole230for writing and include turns252,254,256and258. The coil(s)250′ may be spiral or helical coils, as mentioned above. Turns254and258are assist turns that are recessed from the ABS. One turn252is between the yoke234and a portion242of the top shield242/244. The turn254is further from the ABS. Thus, the turn254is a distance RL′″ from the back gap240. The turn254is aligned with part of the yoke extension236. The back gap240remains between the turns252and254. The turns256and258are analogous to the turns252and254, respectively. The turn258, though recessed from the ABS and partially aligned with the yoke extension236, the back edge of the turn258is further from the ABS than the back edge of the yoke extension236. The magnetic write apparatus220also includes a return pole270having a front gap connection274, a back gap connection272and a central region276. Also depicted inFIG. 6is another configuration in which current may be driven through the turns252,254,256and258.

The magnetic write apparatus220′ may share the benefits of the magnetic write apparatuses120,120′ and220. Because of the configuration of the turns252,254,256and258, the yoke length may be reduced in a manner analogous to that described above. The response time of the pole230may be reduced and data written at a higher rate. Use of the assist turns254and258, more current can be driven close to the pole230despite the reduced yoke length. As a result, a higher magnetic field may be generated in the main pole230for the same write current driven through the coil(s)250′. Further, the use of the return pole270having front gap connection274and the back gap connection272may improve the WATER for the write apparatus220. Thus, the improved data rate and field may be attained without adversely affecting WATER.

FIG. 7depicts a plan view of an exemplary embodiment of a magnetic write apparatus280. For simplicity, only a portion of the magnetic recording apparatus280is shown.FIG. 7is not to scale for clarity. The magnetic write apparatus280is analogous to the magnetic write apparatus120,120′,220and220′. Consequently, analogous components have similar labels. The write apparatus280thus includes a pole281analogous to the pole130/230. For simplicity, other components of the write apparatus280are not shown. In the embodiment shown, the yoke and yoke extension region have a substantially rectangular footprint. However, other shapes are possible.

FIG. 8depicts a plan view of an exemplary embodiment of a magnetic write apparatus280′. For simplicity, only a portion of the magnetic recording apparatus280′ is shown.FIG. 8is not to scale for clarity. The magnetic write apparatus280′ is analogous to the magnetic write apparatus120,120′,220,220′ and280. Consequently, analogous components have similar labels. The write apparatus280thus includes a pole281′ analogous to the pole130/230/281. For simplicity, other components of the write apparatus280′ are not shown. In the embodiment shown, the yoke and yoke extension region have a substantially oval footprint. However, other shapes are possible. Various configurations have been depicted inFIGS. 2-8. Although specific features have been highlighted, one of ordinary skill in the art that the features described herein may be combined in other manners not explicitly depicted.

FIG. 9depicts an exemplary embodiment of a method300for providing a magnetic recording apparatus having a pole that may have a shortened yoke length. For simplicity, some steps may be omitted, interleaved, combined and/or include substeps. The method300is also described in the context of providing a magnetic recording head100′ depicted inFIG. 4. The method300may also be used to fabricate other magnetic recording apparatuses including but not limited to any combination of120,120′,220,220′,280and/or280′. In addition, the method300may be used to fabricate multiple magnetic recording heads at substantially the same time. The method300is also described in the context of particular layers. A particular layer may include multiple materials and/or multiple sub-layers. The method300also may start after formation of other portions of the magnetic recording apparatus. For example, the method300may start after a read apparatus, return pole/shield and/or other structure have been fabricated.

Referring toFIGS. 4 and 9, the return pole170may optionally be provided, via step302. In some embodiments, the back gap connection172and/or the front gap connection174may be omitted. The pole130is provided, via step304. Step304may include using a damascene process. For example, a trench may be formed in a layer and the material(s) for the pole130deposited and patterned. One or more ferromagnetic materials are deposited. The pole tip132, yoke134and yoke extension136may be formed. Other methods may also be used to form the pole130including but not limited to full film deposition of magnetic materials and removal for example via milling and/or lapping.

The write gap146may be provided, via step306. In addition, the back gap140is formed, via step308. The coil(s)150are provided, via step310. Portions of step310may thus be interleaved with the remaining steps of the method300. For example, the turns156and158may be provided before the formation of the pole130. However, the other portions of the coil(s)150may be provided after the pole130has been formed. Step310may also include depositing and patterning the material(s) used for the coil(s)150. Step310may include forming helical coil(s) formed of the coils150. Alternatively, one or two spiral coils may be formed using turns152,154,156and158. The turns152,154,156and158are also located as depicted in the drawings. For example, the turn152is separated from the turn154by the back gap140. The shield(s)142/144may also optionally be provided, via step312.

Using the method300, the magnetic write apparatuses120,120′,220,220′,280and/or280′ may be provided. Thus, the benefits of the magnetic apparatuses120,120′,220,220′,280and/or280′ may be achieved.