Abstract:
A magnetoresistive head having a split coil structure including multiple, similar coil layers separated by an insulator and joined at their ends to define parallel electrical paths. The coil passes through a magnetic yoke having an open end and a closed end and is electrically insulated from the yoke. The parallel electrical paths of the separate coil layers can each be modeled as a resistor in series with an inductor, each of the paths also being in parallel with a capacitor. The split coil has a much faster current rise time than a comparable single layer coil or than multiple coils connected in series. Since the coil current provides the magneto-motive force for imparting a signal on a passing recording medium, the decreased current rise time corresponds to an increased data recording rate.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to magnetic disk data storage systems, and more particularly to magnetic write transducers and methods of making same. 
     Magnetic disk drives are used to store and retrieve data for digital electronic apparatuses such as computers. In FIGS. 1A and 1B, a magnetic disk data storage system  10  of the prior art includes a sealed enclosure  12 , a disk drive motor  14 , a magnetic disk  16 , supported for rotation by a drive spindle S 1  of motor  14 , an actuator  18  and an arm  20  attached to an actuator spindle S 2  of actuator  18 . A suspension  22  is coupled at one end to the arm  20 , and at its other end to a read/write head or transducer  24 . The transducer  24  (which will be described in greater detail with reference to FIG. 2A) typically includes an inductive write element with a sensor read element. As the motor  14  rotates the magnetic disk  16 , as indicated by the arrow R, an air bearing is formed under the transducer  24  causing it to lift slightly off of the surface of the magnetic disk  16 , or, as its is termed in the art, to “fly” above the magnetic disk  16 . Alternatively, some transducers, known as “contact heads,” ride on the disk surface. Various magnetic “tracks” of information can be written to and/or read from the magnetic disk  16  as the actuator  18  causes the transducer  24  to pivot in a short arc as indicated by the arrows P. The design and manufacture of magnetic disk data storage systems is well known to those skilled in the art. 
     FIG. 2A depicts a magnetic read/write head  24  including a substrate  25  above which a read element  26  and a write element  28  are disposed. Edges of the read element  26  and write element  28  also define an air bearing surface ABS, in a plane  29 , which can be aligned to face the surface of the magnetic disk  16  (see FIGS.  1 A and  1 B). The read element  26  includes a first shield  30 , an intermediate layer  32 , which functions as a second shield, and a read sensor  34  that is located within a dielectric medium  35  between the first shield  30  and the second shield  32 . The most common type of read sensor  34  used in the read/write head  24  is the magnetoresistive (AMR or GMR) sensor, which is used to detect magnetic field signals from a magnetic medium through changing resistance in the read sensor. 
     The write element  28  is typically an inductive write element which includes the intermediate layer  32 , which functions as a first pole, and a second pole  38  disposed above the first pole  32 . The first pole  32  and the second pole  38  are attached to each other by a backgap portion  40 , with these three elements collectively forming a yoke  41 . The combination of a first pole tip portion  43  and a second pole tip portion  45  near the ABS are sometimes referred to as the yoke tip portion  46 . A write gap  36  is formed between the first and second poles  32  and  38  in the yoke tip portion  46 . The write gap  36  is filled with a non-magnetic, electrically insulating material that forms a write gap material layer  37 . This non-magnetic material can be either integral with (as is shown here) or separate from a first insulation layer  47  that lies below the second pole  38  and extends from the yoke tip portion  46  to the backgap portion  40 . 
     Also included in write element  28  is a conductive coil  48 , formed of multiple winds  49  which each have a wind height Hw. The coil  48  can be characterized by a dimension sometimes referred to as the wind pitch P, which is the distance from one coil wind front edge to the next coil wind front edge, as shown in FIG.  2 A. As is shown, the wind pitch P is defined by the sum of the wind thickness Tw and the separation between adjacent winds Sw. The conductive coil  48  is positioned within a coil insulation layer  50  that lies above the first insulation layer  47 . The first insulation layer  47  thereby electrically insulates the winds  49  from each other and from the second pole  38 . 
     The configuration of the conductive coil  48  can be better understood with reference to a plan view of the read/write head  24  shown in FIG. 2B taken along line  2 B— 2 B of FIG.  2 A. Because the conductive coil extends beyond the first and second poles, insulation may be needed beneath, as well as above, the conductive coil to electrically insulate the conductive coil from other structures. For example, as shown in FIG. 2C, a view taken along line  2 C— 2 C of FIG. 2A, a buildup insulation layer  52  can be formed adjacent the first pole, and under the conductive coil layer  48 . As will be appreciated by those skilled in the art, these elements operate to magnetically write data on a magnetic medium such as a magnetic disk  16  (see FIGS.  1 A and  1 B). With reference to FIG. 3, the coil defines an electrical circuit which can be modeled as a head resistance Rh in series with a head inductance Lh, both of which are in parallel with a head capacitance Ch. 
     More specifically, an inductive write head such as that shown in FIGS. 2A-2C operates by passing a writing current through the conductive coil layer  48 . Because of the magnetic properties of the yoke  41 , a magnetic flux is induced in the first and second poles  32  and  38  by write currents passed through the coil layer  48 . The write gap  36  allows the magnetic flux to fringe out from the yoke  41  (thus forming a fringing gap field) and to cross a magnetic recording medium that is placed near the ABS. A critical parameter of a magnetic write element is a trackwidth of the write element, which defines track density. For example, a narrower trackwidth can result in a higher magnetic recording density. The trackwidth is defined by the geometries in the yoke tip portion  46  (see FIG. 2A) at the ABS. These geometries can be better understood with reference to FIG.  2 C. As can be seen from this view, the first and second poles  32  and  38  can have different widths W 1  and W 2  respectively in the yoke tip portion  46  (see FIG.  2 A). In the shown configuration, the trackwidth of the write element  28  is defined by the width W 2  of the second pole  38 . Thus, accurate definition of the trackwidth is critical during the fabrication of the write element. 
     However, the control of trackwidth, and coil pitch can be limited by typical fabrication processes, an example of which is shown in the process diagram of FIG.  4 A. The method  54  includes an operation  56  of providing a first pole. This operation can include, for example, forming a plating dam, plating and then removing the dam. In an operation  58 , a write gap material layer is formed over the first pole. In particular, the write gap material layer is formed over an upper surface of the first pole. Also, in operation  58 , a via is formed through the write gap material layer to the first pole in the backgap portion  40  (see FIG.  2 A). In the instance herein described, the write gap material layer extends above the first pole in the area between the yoke tip portion and the backgap portion, although in other cases the write gap material layer may not be above this area. A buildup insulation layer is typically formed by depositing (e.g., spinning) and patterning photoresistive material and then hard baking the remaining photoresistive material. Such processes often result in the height of the buildup insulation layer being non-uniform. 
     In an operation  62  the first coil layer is formed above the write gap material layer and the buildup insulation layer. This can include first depositing a seed layer above the first pole. Typically, photoresistive material can then be deposited and patterned. With the patterned photoresistive material, conductive material can be plated. With removal of the photoresistive material, the remaining conductive material thereby forms the first coil layer. 
     Unfortunately, when there is a difference in height between the write gap material layer and the buildup insulation layer, the patterning of the photoresistive material for the first coil layer can be complicated. In particular, it can be difficult to pattern the various heights to have consistent geometries. More specifically, winds of the resulting first coil layer can be wider at lower levels than at higher levels, such as between the first and second poles. Thus, for a given pitch, such greater width at the lower levels can result in smaller distances between winds. This can, in turn, result in electrical conduction between winds which can be detrimental to write performance. To avoid such electrical shorting, the minimum wind pitch can be set to a desired value that will result in adequate yield of non-shorting conductive coil layers. Because the coil winds are more narrow between the first and second poles, the resulting pitch there is typically greater than, and limited by this minimum. For example, typical wind pitches between the first and second poles may be limited to no less than about 3 microns. For a given number of winds and wind thickness, this in turn limits the minimum yoke length, and thereby limits the data transfer rate and data density as described above. For example, a pitch of about 3 microns maybe adequate for recording densities on the order of about 2 Gb/sq.in., however, these typical pitches can be inadequate for larger recording densities, such as about 10 Gb/sq.in. 
     In operation  64 , the method  54  further includes forming a coil insulation layer above the first coil layer that was formed in operation  62 . In an operation  66  a second pole is formed above the coil insulation layer of operation  64 . 
     Still another parameter of the write element performance is the stack height SH, the distance between the top surface of the first pole  32  and the top of the second pole  38 , as shown in FIG.  2 A. Of course this height is affected by the thickness of the first insulation layer  47 , the thickness of the coil layer  48  and any other coil layers that might be included, and the height of the coil insulation layer  50  and any other coil insulation layers that might be included. The stack height can be an indicator of the apex angle α, which partially characterizes the topology over which the second pole must be formed near the yoke tip portion. Typically, the reliability of the write element decreases as the apex angle increases. This is due, at least in part, to the corresponding increased difficulty, particularly in the yoke tip portion  46 , of forming the second pole  38  over the higher topography of the stack. For example, the definition of the second pole width W 2 , shown in FIG. 2C, including photoresist deposition and etching, can be decreasingly reliable and precise with increasing topography. When demand for higher density writing capabilities drives yoke tip portions to have smaller widths W, this aspect of fabrication becomes increasingly problematic. 
     Also, with higher topography, when the second pole is formed, for example by sputtering or plating, the material properties of the second pole in the sloped region, adjacent the second pole tip region  45 , can be undesirable. Thus, this decreased reliability results in undesirable lower production yield. A device with a lower apex angle is, therefore, desirable. 
     Magnetic recording density is equal to track density times linear density. Increasing linear density results in high data transfer rate. One may expect 1000 megabits per second will be required in year 2000. To support higher data rate applications, the second pole can otherwise be formed by lamination, which can be more time consuming than without lamination. In order to obtain faster recording speeds, and therefore higher data transfer rates, it may be desirable to have a shorter yoke length YL because this can shorten the flux rise time. The relationship can be seen in the graph of yoke length YL versus flux rise time shown in FIG.  4 B. This relationship can be more fully understood with reference to “Ultrafast Laser Diagnostics and Modeling for High-speed Recording Heads”, IEEE Transactions on Magnetics, Vol. 35 No. 2, 623 (1999) by Zhupei Shi, W. K. Hiebert and M. R. Freeman, the entirety of which is hereby incorporated by reference. 
     Another important parameter in the write element is the number of winds  49  in the coil layer  48 , which determines the magnetic motive force (MMF) of a write element. With increasing number of winds  49  between the first and second poles  32 ,  38 , the fringing field is stronger and, thus, the write performance increases. However, the number of winds is limited by the yoke length YL, shown in FIG. 2A, and the wind pitch P between adjacent winds  49 . 
     As will be appreciated from the above, the design of a write element having the ability to provide increased data rate capabilities is limited by many factors. For example it is desirable to minimize yoke length as well as stack height. However, a write head must also provide sufficient magneto-motive force, which is limited by current flow and the number of winds in the yoke. The number of winds can not be increased without increasing yoke length or stack height and the amount of current is limited by the amount of heat generation which can be tolerated within the head, as heat generation can effect the read characteristics of the head by causing thermal stresses which will be interpreted by the read sensor as magnetic signals. 
     Therefore, there remains a need for a fundamentally different approach to increase data rate capability in a write element in light of the other aforementioned design parameters and manufacturing limitations. The desired head would be capable of increasing data recording rate while recording with sufficient magneto-motive force data density on a passing magnetic disk and. Preferably, such a write element would have a low stack height and short yoke length as well as a small track width. Such a write element should also lend itself to cost effective manufacturing techniques. 
     SUMMARY OF THE INVENTION 
     The present invention provides a magnetic write element providing increased data rate recording performance while maintaining sufficient magneto-motive force and data density. The write element includes a magnetic yoke having an open end and a closed end and an open interior there between. A split coil is also provided, which has a portion of its winds passing through the open interior of the yoke. The split coil is electrically insulated from the yoke. The coil is split so that it defines first and second coil layers separated by a thin dielectric coil separation layer. The first and second coil layers are joined at their inner and outer ends to define parallel electrical circuits. 
     More particularly, the present invention is embodied in a combination read/write head having a read element and a write element, both of which are built upon a ceramic substrate. The read element includes a first shield disposed upon the substrate and a second shield disposed above the first shield. A first layer of dielectric material, sandwiched between the first and second shields contains a read sensor for detecting a magnetic signal from a recording medium passing thereby. The first layer of dielectric material extends beyond the edges of the shields filling the space from the substrate to the upper surface of the second shield. 
     The write element includes a first pole and a second pole joined together to form the magnetic yoke. The second shield provides a portion of the first pole of the write element. The first pole also includes a pedestal at the write gap, the open end of the yoke. The second shield is constructed of a magnetic material such as Ni 80 Fe 20 , and the pedestals can either be constructed of the same material at the shield or can be constructed of a material having a higher saturation moment. 
     A layer of dielectric material covers the first shield having an upper surface which is flush with the upper surfaces of the pedestals. The split coil is formed on top of this second dielectric layer and has contact pads at its inner and outer ends. The split coil can preferably be constructed of copper and its first and second coil layers are essentially identical and located one over the other. The first and second coil layers are separated by a very thin insulating layer which is preferably constructed of Al 2 O 3 . The first and second coil layer each share in common the inner and outer contact pads, thereby forming a parallel electrical circuit to which voltage can be applied at the contact pads. 
     A coil insulation layer covers the coil and is formed so that it does not cover either of the pedestals or the contact pads. A thin layer of non-magnetic, electrically insulating write gap material covers the coil insulation layer and also covers the pedestal at the open end of the yoke. The write gap material does not cover the back gap area or the coil contact pads. The second pole sits atop the write gap material above the first pole and contacts the first pole in the back gap area at the closed end to complete the yoke. The second pole is constructed of a magnetic material with a high magnetization such as Ni 45 Fe 55 . 
     The first and second coil layers define a parallel electrical circuit which can be modeled as two electrical paths each having a resistor in series with an inductor, both parallel paths being in parallel with a capacitor. The two inductive paths have the advantageous property of an increased current rise time as compared with a single inductive path, while still maintaining the same magneto-motive force. Furthermore, a split coil can achieve this while having essentially the same height as a single coil. In this way the write element of the present invention provides greatly increased data rate while maintaining other critical design parameters. 
     Other embodiments are also possible. For example, the write gap material could be disposed between the coil and the first pole or between the coil and the coil insulation layer. Also, the first pole could be constructed without any pedestals. In another embodiment, the split coil could be constructed with three or more coil layers, depending upon design requirements. 
     These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following descriptions of the invention and a study of the several figures of the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, with like reference numerals designating like elements. 
     FIG. 1A is a partial cross-sectional front elevation view of a magnetic data storage system; 
     FIG. 1B is a top plan view taken along line  1 B— 1 B of FIG. 1A; 
     FIG. 2 is a cross-sectional view of a prior art read/write head of the magnetic disk drive assembly of figures  1 A and  1 B; 
     FIG. 2B is a plan view taken along line  2 B— 2 B of FIG. 2A; 
     FIG. 2C is an ABS view taken along line  2 C— 2 C of FIG. 2A; 
     FIG. 3 is a schematic of an electrical circuit defined by a write element of the prior art; 
     FIG. 4A is a process diagram of a method for forming a write element of the prior art; 
     FIG. 4B is a graph of yoke length YL versus flux rise time; 
     FIG. 5 is a cross sectional view of a read/write head of the present invention; 
     FIG. 6 is a perspective view of a split coil of the present invention; 
     FIG. 7 is a schematic diagram of an electrical circuit defined by the write element of the present invention; 
     FIG. 8A is a graph illustrating the current rise time of a head of the present invention as compared with that of a prior art head; 
     FIG. 8B is a graph illustrating the data rate of a head of the present invention as compared with that of a prior art head; 
     FIG. 9 is a process diagram of a method of manufacturing a write element of the present invention; 
     FIGS. 10-15 are cross sectional views of a read/write head of the present invention in progressive intermediate stages of development; 
     FIG. 16 is a plan view of a coil of the present invention showing locations for localized etching; 
     FIG. 17-19 are cross sectional views of a read/write head of the present invention in progressive intermediate stages of development. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIG. 5, the present invention is embodied in a magnetoresistive head  500  including a read portion  502  and a write portion  504  all of which is built upon a substrate  506 . The read portion includes first and second shields  508  and  510 , separated by a first dielectric layer  512 . The first dielectric layer  512  extends beyond the edges of the shields  508  and  510 , extending to a level flush with an upper surface  514  of the second shield  510 . A read sensor  516  is embedded within the dielectric layer for sensing a magnetic signal from a recording medium passing thereby. 
     With continued reference to FIG. 5, the write element  504  also includes a magnetic yoke  518  having an open interior through which passes an electrically conductive split coil  520  which is electrically insulated from the yoke  518 . The write element  504  has a write gap portion  517  at one end and aback gap portion  519  at its opposite end. 
     More particularly, the yoke  518  includes a first magnetic pole  522  and a second magnetic pole  524  formed thereover. The second shield  510  of the read element serves as a portion of the first pole  522  of the yoke  518 . The first pole  522  also includes a write gap pedestal  526  which extends upward from the upper surface  514  of the shield  510  in the write gap portion of the write element  504 . The write gap pedestal  526  has a smooth flat upper surface  528 . Opposite the write gap pedestal, the first pole further includes a back gap pedestal  530  also extending from the upper surface  514  of the shield  510 . The back gap pedestal has a smooth, flat upper surface  532  which is coplanar with the upper surface  528  of the write gap pedestal. In the preferred embodiment, the shield  510  as well as the pedestals  526  and  530  are constructed of Ni 80 Fe 20 . Alternatively, one or both of the pedestals  526  and  530  are constructed of a high saturation moment material such as Ni 45 Fe 55 . 
     With continued reference to FIG. 5, a second dielectric layer  534  covers the second shield  510  and extends beyond the edges thereof. The second dielectric layer has a smooth flat upper surface which is flush with the upper surfaces  528  and  532  of the pedestals  526  and  530 . While the second dielectric layer  534  can be constructed of any suitable electrically insulating material, it is preferably constructed of Al 2 O 3 . 
     The split coil  520  sits atop the dielectric layer  534 , and is formed so that a portion of the coil passes over the first pole  522  between the write gap portion  517  and the back gap portion  519 . As can be more clearly understood with reference to FIG. 6 in conjunction with FIG. 5, the split coil  520  consists of a first coil layer  536  and a similar second coil layer  538  formed above the first coil layer  536  and separated therefrom by an electrically insulating coil separation layer  540 . The first and second coil layers  536  and  538  are joined by common coil contacts pads  542  and  544  formed at the inner and outer ends of the split coil  520  respectively. In this way, the first and second coil layers  536  and  538  define parallel electrical circuits when a current is supplied at the contacts  542  and  544 . Preferably the coil has a pitch of less than 2 microns in order to allow the yoke to have a small yoke length. 
     While the preferred embodiment has a coil  520  which is split once to include two coil layers  536  and  538 , alternate embodiments, not shown, having three or more separated coil layers are also possible. The split coil  20 , including the first and second coil layers  536  and  538  as well as the contacts  542  and  544  can be constructed of any suitable non-magnetic metal and is preferably constructed of copper. The coil separation layer, which can be constructed of any suitable dielectric insulating material, is preferably constructed of Al 2 O 3 . 
     With continued reference to FIG. 5, the split coil  520  is covered with a coil insulation layer  546  which electrically insulates the winds of the coil from one another as well as insulating the coil  520  from surrounding structure. While the coil insulation layer could be constructed of any suitable electrically insulating material it is preferably constructed of a spun, cured photoresist. The coil insulation layer  546  has a smoothly sloping edge adjacent the write gap pedestal  526 . 
     A thin layer of non-magnetic, electrically insulating write gap material  548  covers the coil insulation layer  546  and also covers the upper surface  528  of the write gap pedestal  526 . The write gap material is formed so that it does not cover the back gap pedestal  530  or the contacts  542  and  544 . While the write gap material could be constructed of many electrically insulating, non-magnetic materials it is preferably constructed of Al 2 O 3 . 
     With further reference to FIG. 5, the second pole  524  covers the write gap material layer  548  above the first pole  522 . The second pole contacts the upper surface  532  of the back gap pedestal  530 , thereby joining with the first pole  522  to form the magnetic yoke  518 . While the second pole  524  could be constructed of any suitable magnetic material, it is preferably formed of Ni 45 Fe 55  and is deposited by plating. 
     With reference to FIG. 7, the split coil  520  of the present invention provides a pair of parallel electrical paths through which to pass a current. The coil layers  536  and  538  can be modeled electrically as two branches of resistance and inductance: Rh 1 +Lh 1  and Rh 2 +Lh 2 . Both circuit segments are in parallel with one another and are also in parallel with a head capacitance Ch. This is to be distinguished from prior art write heads, illustrated with reference to FIG. 3, in which the coil is modeled as a head resistance in series with a head inductance both of which are in parallel with a head capacitance. With reference to FIGS. 8A and 8B, it can be seen that the parallel electrical circuit provided by the split coil structure provides a larger overshoot and a shorter current rise time. Analysis here has shown a 44% improvement in current rise time. 
     With reference to FIG. 9, a process  900  for constructing the head  500  of present invention will be described. With the read element already having been constructed, the process  900  begins with a step  902  of constructing the first pole  522  which includes building the write gap and back gap pedestals  526  and  530  on top of the second shield  510 . The pedestals are constructed of Ni 55 Fe 45  and are deposited by masking and plating. Then in a step  904 , the second dielectric layer  534  is deposited onto the first pole. The dielectric layer  534  is formed by first depositing the Al 2 O 3  so that it covers the entire first pole  522  including the pedestals  526  and  530 . The Al 2 O 3  is then polished by a chemical mechanical polishing process (CMP) until the upper surfaces  528  and  532  of the pedestals  526  and  530  are exposed and planarized. As can be more clearly seen with reference to FIG. 10, this results in a smooth flat surface across the tops of the dielectric layer and the pedestals. On top of this smooth flat surface, a copper seed layer is deposited. The copper seed layer provides an electrically conducting substrate on which to plate the coil in a subsequent plating process. 
     The process continues with a step  906  of depositing a layer of Silicon Oxide  1102 , as can be seen with reference to FIG.  11 . Then, in a step  908 , a layer of photoresist is deposited and masked on top of the Silicon Oxide layer to reveal the desired coil pattern. This structure can be more clearly understood with reference to FIG.  12 . In a step  910 , an etching process is performed which removes the Silicon Oxide  1102  according to the coil pattern revealed by the masked photoresist as is shown with reference to FIG.  13 . Subsequently, in a step  912 , the first copper coil layer  536  is deposited. This can be seen with reference to FIG.  14 . Then, in a step  914 , a thin layer of Al 2 O 3    1502  is deposited to provide the coil separation layer  540 , as can be seen with reference to FIG.  15 . In a step  916  the photoresist layer is stripped which leaves the Al 2 O 3  only in the area of the coil pattern. With reference to also FIG. 16, in a step  918 , the coil separation layer  540  is etched at the locations of the contact pads  542  and  544 . 
     In a step  920 , another layer of copper  1702  is deposited as shown with reference to FIG.  17 . The step  920  includes depositing a second seed layer and plating the full film copper layer so that it covers the Silicon Oxide layer  1102  as well as the Al 2 O 3  in the coil pattern area. With reference also to FIG. 18, in a step  922 , a CMP process is conducted sufficiently to generate individual coil winds having flat upper surfaces. Thereafter, in a step  924 , the Silicon Oxide layer  1102  is removed by an etching process, as can be understood more clearly with reference to FIG.  19 . 
     With reference to FIG. 5, the split coil having been formed, the process  900  continues with a step  926  of depositing the coil insulation layer  546  over the coil. The coil insulation layer  546  is a photoresist which is spun onto the coil. The photoresist is masked to reveal the back gap pedestal  530  and the coil contact pads  542  and  544 . The photoresist is then cured, causing it to form gradually sloped edges. In a step  928 , a thin layer of non-magnetic, electrically insulating write gap material is deposited over the coil insulation layer and the write gap pedestal  526 . The write gap material is preferably Al 2 O 3 . Over the write gap material, the second pole  524  is formed in a step  930 . The second pole  524  is preferably constructed of Ni 45 Fe 55  and is deposited by plating so that it contacts the back gap pedestal  530 . In this way the first and second poles  522  and  524  together form the yoke  518 . 
     In an alternate embodiment of the invention, not shown, the write gap material layer is formed prior to forming the coil so that the write gap material layer sits between the coil and the second dielectric layer. This embodiment functions in essentially the same way as the preferred embodiment, using a split coil to increase current rise time. 
     In another embodiment of the invention, also not shown, the first pole is formed without one or both of the write gap and back gap pedestals. This embodiment can either include a dielectric layer to separate the coil from the first pole, or alternatively can use the write gap material to provide such separation. 
     In summary, the present invention provides a write element which employs a fundamentally unique coil design to provide a significant decrease in current rise time. This provides a corresponding increase in data rate capability. While the invention has been described herein in terms of several preferred embodiments. Other embodiments of the invention, including alternatives, modifications, permutations and equivalents of the embodiments described herein, will be apparent to those skilled in the art from consideration of the specification, study of the drawings, and practice of the invention. Therefore, the embodiments and preferred features described above should be considered exemplary, with the invention being defined by the appended claims which include all such alternatives, modifications, permutations and equivalents as fall within the true spirit and scope of the invention.