Perpendicular magnetic recording with multiple antiferromagnetically coupled layers

Provided herein is an apparatus including a top continuous layer and a bottom continuous layer under the top continuous layer. The top continuous layer and the bottom continuous layer are antiferromagnetically coupled. A number of granular columns are under the bottom continuous layer. The number of granular columns include at least a first granular layer under the bottom continuous layer and a second granular layer also under the first granular layer. The first granular layer and the second granular layer are separated by a non-magnetic spacer. The first granular layer and the second granular layer are ferromagnetically coupled. The first granular layer is antiferromagnetically coupled to the bottom continuous layer.

BACKGROUND

Certain devices use disk drives with perpendicular magnetic recording media to store information. For example, disk drives can be found in many desktop computers, laptop computers, and data centers. Perpendicular magnetic recording media store information magnetically as bits. Bits store information by holding and maintaining a magnetization that is adjusted by a disk drive head. In order to store more information on a disk, bits are made smaller and packed closer together, thereby increasing the density of the bits. Therefore as the bit density increases, disk drives can store more information. However as bits become smaller and are packed closer together, the bits become increasingly susceptible to erasure, for example due to thermally activated magnetization reversal or adjacent track interference.

SUMMARY

Provided herein is an apparatus including a top continuous layer and a bottom continuous layer under the top continuous layer. The top continuous layer and the bottom continuous layer are antiferromagnetically coupled. A number of granular columnar layers are under the bottom continuous layer. The number of granular columnar layers include at least a first granular columnar layer under the bottom continuous layer and a second granular columnar layer also under the bottom continuous layer. The first granular columnar layer and the second granular columnar layer are separated by a non-magnetic spacer. The first granular columnar layer and the second granular columnar layer are antiferromagnetically coupled to the bottom continuous layer. These and other features and advantages will be apparent from a reading of the following detailed description.

DESCRIPTION

Before various embodiments are described in greater detail, it should be understood that the embodiments are not limiting, as elements in such embodiments may vary. It should likewise be understood that a particular embodiment described and/or illustrated herein has elements which may be readily separated from the particular embodiment and optionally combined with any of several other embodiments or substituted for elements in any of several other embodiments described herein.

It should also be understood that the terminology used herein is for the purpose of describing the certain concepts, and the terminology is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood in the art to which the embodiments pertain.

As the technology of perpendicular magnetic recording media reaches maturity, it becomes increasingly difficult to continue to increase the storage capacity of recording media (e.g. disk drive disks) or to reduce the size of recording media while maintaining storage capacity. Such challenges may be overcome by increasing the bit density on the recording media. However, increasing the bit density can decrease the signal to noise ratio (“SNR”) below acceptable levels. SNR can be increased by using ultra-thin magnetic films to bring the magnetic read/write head closer to the recording media. However, ultra-thin magnetic films lower the thermal stability of the grains within the bits, thereby increasing the grains' susceptibility to fluctuation and information loss. Embodiments described below address these concerns with a number of antiferromagnetically coupled continuous and granular layers.

It is understood that perpendicular magnetic recording (“PMR”) media includes both granular magnetic layers and continuous magnetic layers. Granular layers include grains that are segregated in order to physically and magnetically decouple the grains from one another. Segregation of the grains may be done, for example, with formation of oxides at the boundaries between adjacent magnetic grains. As such, the segregated magnetic grains form a granular layer. When multiple granular layers stacked together they form a columnar structure, where the magnetic alloys are hetero-epitaxially grown into columns while the oxides segregate into grain (column) boundaries. PMR media may include both granular layers and continuous layers. In various embodiments, continuous layers include zero or much less segregation materials than found in the granular layers.

Referring now toFIG. 1, a PMR media100with antiferromagnetically coupled layers is shown according to one aspect of the present embodiments. A substrate102is provided. In various embodiments, the substrate102is disc shaped may include a non-magnetic metal, alloy, or non-metal. For example, the substrate102may comprise aluminum, an aluminum alloy, glass, ceramic, glass-ceramic, polymeric material, a laminate composite, or any other suitable non-magnetic material.

Overlying the substrate102is a continuous amorphous soft magnetic underlayer (“SUL”)104. The SUL104may include one or more layers of a soft magnetic material. For example, the SUL104may be a 10 to 2000 Å thick layer including a soft magnetic material such as Ni, NiFe, Co, CoZr, CoZrCr, CoZrNb, CoCrTaB, CoCrB, CoCrTa, CoFe, Fe, FeN, FeSiAl, FeSiAlN, FeCoC, etc. In embodiments including multiple SUL layers, the multiple SUL layers may be either ferromagnetically coupled or antiferromagnetically coupled. In addition, the multiple SUL layers may be separated by one or more layers (e.g. Ru layers).

Overlying the SUL104is a seed layer106. In various embodiments the seed layer106includes materials with a face-centered cubic (“fcc”) structure in (111) orientation. For example, the seed layer106may include Ni or Ni alloy. The seed layer106fixes the orientation for an overlying first intermediate layer108(e.g. bottom layer). In various embodiments, the first intermediate layer108is continuous and includes materials with a hexagonal close-packed (“hcp”) structure in (0002) orientation that are deposited in a low pressure environment in order to provide a hcp lattice for the growth of a subsequent layer. For example, the first intermediate layer108may include Ru, RuCr, RuCrMn, RuCo, RuCoCr, etc. that was deposited with a pressure of 5 mTorr.

A second intermediate layer110(e.g. middle layer) overlies the first intermediate layer108(e.g. bottom layer). In various embodiments, the second intermediate layer110is granular and includes materials with a hcp structure in (0002) orientation that are deposited in a high pressure environment in order to provide a granular top surface for the growth of a subsequent layer. For example, the second intermediate layer110may include Ru that was deposited with a pressure of 100 mTorr. It is understood that the low 5 mTorr and high 100 mTorr are merely exemplary and not intended to limit the scope of the embodiments. In some embodiments, various elements (including Ru) may use different pressures or ranges of pressures to fix the hcp and granularity.

A third intermediate layer111(e.g. top layer) overlies the second intermediate layer110(e.g. middle layer). In various embodiments, the third intermediate layer111is granular and includes materials with a hcp structure in (0002) orientation that are deposited in a high pressure or lower pressure environment, with or without oxygen, in order to provide a granular top surface for the growth of a subsequent layer. For example, the third intermediate layer111may include Ru along with an oxide (e.g. SiO2, TiO2, B2O3, etc.).

Overlying the third intermediate layer111are multiple granular columns112that include magnetic materials with hcp structure (e.g. Co, CoCr, CoCrPt, CoCrTa, CoCrPtTa, CoCrPtRu, CoCrPtTaRu, etc.). For clarity of illustration, only a few of the multiple granular columns112are shown. However, it is understood that various embodiments may include any number of granular columns112. It is also understood that the shape and size of the granular columns depicted inFIG. 1is for illustration purposes. The actual shape and size of the granular columns may vary from each other.

In various embodiments, each of the granular columns112are separated by boundaries114that are non-magnetic spacers. In various embodiments, the boundaries114may be, for example, oxides (e.g. SiO2, TiO2, B2O3, etc.) or combinations of oxides. The boundaries114segregate the granular columns112by physically separating and therefore magnetically decoupling the granular columns112from each other. As such, the granular columns112parallel and horizontal to each other with respect to overlying and underlying layers, and the magnetization of the granular columns112is perpendicular to the overlying and underlying layers. Therefore the granular columns112are in the same horizontal plain.

Each of the multiple granular columns112may themselves include granular layers. For example, in some embodiments each of the granular columns112may include a first magnetic granular layer116overlying the third intermediate layer111, a first break layer118overlying the first magnetic granular layer116, and second magnetic granular layer120overlying the first break layer118, a second break layer122overlying the second magnetic granular layer120, and a third magnetic granular layer124overlying the second break layer122. In various embodiments, first magnetic layer116, second magnetic granular layer120, and third magnetic granular layer124are ferromagnetically coupled. Other embodiments may include various numbers of granular layers with or without various numbers of break layers as well as various couplings of layers.

In some embodiments the first break layer118and the second break layer122may be 0-20 Å thick, and include weak magnetic or non-magnetic materials (e.g. Co, Cr, Pt, Ru, B, SiO2, TiO2, or other oxides or alloys). The material and thickness of the first break layer118and the second break layer122are selected to induce ferromagnetic coupling between the first granular layer116and second granular magnetic layer120as well as the second granular magnetic layer120and the third granular magnetic layer124of the multiple granular columns112. In addition, the ferromagnetic coupling strength between layers may be adjusted by controlling the thickness of the break layer between the ferromagnetically coupled layers. Both granular layers and break layers include segregation materials, such as oxides (e.g. SiO2, TiO2, B2O3, etc. or their combinations). The volume fractions of segregation materials inside granular magnetic layers range from 5% to 40%. The volume fractions of segregation materials inside break layers range from 0 to 40%. The segregation materials (e.g. oxides) form a non-magnetic grain (column) boundaries114inside the multiple granular columns112.

In some embodiments the first magnetic layer116may be a harder magnetic layer (e.g. Hk=20 kOe), the second magnetic layer120may be a medium magnetic layer (e.g. Hk=15 kOe), and the third magnetic layer124may be a softer magnetic layer (e.g. Hk=10 kOe). It is understood that the values indicated with respect to layers116,120, and124are merely exemplary and not intended to limit the scope of the embodiments. The terminology harder, medium, and softer is intended to indicate the relative magnetic hardness of layers116,120, and124to each other. The magnetic layers116,118and120inside granular columns112include magnetic materials with hcp structure (e.g. Co, CoCr, CoCrPt, CoCrTa, CoCrPtTa, CoCrPtRu, CoCrPtTaRu, etc.).

A first non-magnetic antiferromagnetic (“AFC”) spacer layer126overlies the multiple granular columns112. In various embodiments the first AFC spacer layer126is a 1-10 Å thick continuous layer that may include, for example, Ru, Rh, or alloys thereof. The material and thickness of the first AFC spacer layer126are selected to induce antiferromagnetic coupling between the third magnetic layer124(e.g. a top surface) of the multiple granular columns112to a first continuous layer128, overlying the first AFC spacer layer126.

It is understood that varying the thickness and/or material of the first AFC spacer layer126may induce either ferromagnetic coupling or antiferromagnetic coupling between the first continuous layer128and the third magnetic layer124of the multiple granular columns112. For example, if a predetermined thickness of the AFC spacer layer126induces antiferromagnetic coupling, ferromagnetic coupling may instead be induced by either increasing or decreasing the thickness of the AFC spacer layer126, in various embodiments. In addition, the coupling strength between the third magnetic layer124and the first continuous layer128may be adjusted by controlling the thickness of the first AFC spacer layer126.

A second non-magnetic AFC spacer layer130overlies the first continuous layer128. In various embodiments the second AFC spacer layer130is a 1-10 Å thick continuous layer that may include, for example, Ru, Rh, or alloys thereof. The material and thickness of the second AFC spacer layer130are selected to induce antiferromagnetic coupling between the first continuous layer128to a second continuous layer132, overlying the second AFC spacer layer130. It is understood that varying the thickness and/or material of the second AFC spacer layer130may induce either ferromagnetic coupling or antiferromagnetic coupling between the second continuous layer132and the first continuous layer128. In addition, the coupling strength between the first continuous layer128and the second continuous layer132may be adjusted by controlling the thickness of the second AFC spacer layer130.

It is understood that one or more layers may be referred to as a layer stack. For example, a combination of the substrate102, the SUL104, the seed layer106, the first intermediate layer108, and the second intermediate layer110may be referred to as a layer stack. Various other combinations of any of the layers described in embodiments may also be referred to as layer stacks.

In the present embodiment, the first continuous layer128is a bottom continuous layer with respect to the second continuous layer132which is a top continuous layer. In various embodiments, the first continuous layer128and the second continuous layer132may include Co—Pt alloys. In some embodiments, the Pt atomic percentage may be in the range of 0-45%. The first continuous layer128and the second continuous layer132may also include multiple other elements, such as, Cr, Ru, Ni, Cu, B, C, etc as dopants or alloying compounds. In various embodiments the multiple other elements may be transition metals with an atomic percentage of 0-30%. The first continuous layer128and the second continuous layer132may also include a small amount of multiple segregation materials, such as, SiO2, TiO2, B2O3, etc. In different embodiments, the first continuous layer128and the second continuous layer132may be the same material or different materials.

Referring now toFIG. 2, the perpendicular magnetic recording media100including a first bit240and a second bit242is shown according to one aspect of the present embodiments. The first bit240includes the granular columns112, the first AFC spacer layer126, the first continuous layer128, the second AFC spacer layer130, and the second continuous layer132. For clarity of illustration, other layers of the perpendicular magnetic recording media100are not illustrated, but are understood to be present (see for exampleFIG. 1). As such, a number of the granular columns112overly an underlying layer stack.

In addition for clarity of illustration, the magnetizations of the grains or layers are depicted by up and down arrows. Therefore, the plurality of granular columns112, the first continuous layer128, and the second continuous layer132are perpendicularly magnetically oriented to the layer stack, as depicted by the up and down arrows. The granular columns112and the second continuous layer132include the same magnetization orientation, as indicated by the up arrow. The first continuous layer128includes an opposite magnetization orientation, as indicated by the down arrow. It is understood that magnetization orientations may also be referred to as positive (+), negative (−), north pole, south pole, etc. However, it is understood that such magnetic representations are simplifications indicating, for example, the general location from which magnetic field lines emerge and reenter.

The second bit242includes corresponding layers to the layers in the first bit240. As such the second bit242includes the second bit layers: granular columns212, AFC spacer layer226, first continuous layer228, second AFC spacer layer230, and second continuous layer232. For clarity of illustration, other layers are not illustrated, but are understood to be present.

The layers of the first bit240magnetically orient in response to one another, and the layers of the second bit242magnetically orient in response to one another. Therefore, the magnetizations (figuratively depicted with up and down arrows) of the layers of the first bit240are independent of the magnetizations (figuratively depicted with up and down arrows) of the layers of the second bit242. As such, the first bit240may have different magnetizations than the second bit242. Alternatively, the first bit240may have the same magnetizations (not shown) of the second bit242.

As such, in a non-limiting example the first bit240may be referred to as a first region and the second bit242may be referred to as a second region. The granular columns112in the first region may include a first top magnetic granular layer, a first middle magnetic granular layer and a first bottom magnetic granular layer under a bottom continuous layer in the first region (e.g. the first continuous layer128). The granular columns212in the second region may include a second top magnetic granular layer, second middle magnetic granular layer and a second bottom magnetic granular layer under the bottom continuous layer in the second region (e.g. the first continuous layer228). Therefore, the first top, first middle, first bottom, second top, second middle and, second bottom magnetic granular layers are horizontally beside each other in a same horizontal plain with respect to the bottom continuous layer. In addition, the first top granular layer is antiferromagnetically coupled to the bottom continuous layer in the first region, as indicated by the arrows. The second top magnetic granular layer is antiferromagnetically coupled to the bottom continuous layer in the second region, as indicated by the arrows. Furthermore, the arrows illustrate that the first region and the second region may include different magnetization orientations. As such, the first region and the second region magnetically orient independently from each other, and may have the same or different magnetizations.

Referring now toFIG. 3, the first bit240magnetically responding to a read/write head350is shown according to one aspect of the present embodiments. It is understood that in various embodiments the read/write head350may be a read head or a write head, and the various embodiments may therefore include a separate read head and a separate write head. Further embodiments may include one or more read heads, write heads, and/or read/write heads.

During a writing operation, the read/write head350generates a magnetic field strong enough to orient the magnetization of the second continuous layer132to the desired direction. In the illustrated example, the magnetization of the second continuous layer132is therefore switched, as indicated by the black down arrow. In response to the antiferromagnetic coupling between the first continuous layer128and the second continuous layer132as well as the magnetic field of the read/write head350, the magnetization of the first continuous layer128is switched. Furthermore, in response to the AFC coupling between the first continuous layer128and the multiple granular columns112as well as the magnetic field of the read/write head350the multiple granular columns112are also switched, as indicated by the corresponding black up and black down arrows.

During a reading operation, the read/write head350reads the signals carried by the magnetization of the second continuous layer132, which matches the magnetization of the multiple granular columns112. In the illustrated example, the magnetizations of the second continuous layer132and the multiple granular columns112, as indicated by the black down arrows, are the same because of their antiferromagnetic couplings with the first continuous layer128, with an opposite magnetic magnetization indicated by the black up arrow.

In various embodiments, the second continuous layer132is thicker than the first continuous layer128, has higher magnetization, or has a higher product of thickness and saturation magnetization (“Mst”). As a result of the higher Mst, the moment generated by the second continuous layer132is stronger than the moment generated by the first continuous layer128. Therefore, the read/write head350can detect the moment of the second continuous layer132because it is not totally canceled out by the opposite moment of the first continuous layer128. As a result, the read/write head350can perform read operations on the relatively closer second continuous layer132(as compared to the relatively further multiple granular columns112).

For example, if the first continuous layer128fully canceled out the moment of the second continuous layer132, then the read/write head350would need to read the multiple granular columns112. However, the multiple granular columns112are much further away from the read/write head350. As a result, read operations would be relatively more blurred, with lower resolution.

On the other hand, in embodiments presented herein the magnetization of the second continuous layer132is not canceled by the magnetization of the first continuous layer128. Therefore, the read/write head350interacts with the closer second continuous layer132. Due to AFC coupling between the second continuous layer132and first continuous layer128, the second continuous layer132has a higher switching field than the case when it is ferromagnetically coupled to the first continuous layer128. In addition, the second continuous layer132has a lower switching field strength than the multiple granular columns112, thereby making write operations relatively easier. However, the robustness of magnetic information is maintained because the second continuous layer132is coupled to (through the first continuous layer128) and matches the magnetization of the magnetically harder multiple granular columns112. For example, in the illustrated embodiment the second continuous layer132(with a magnetization represented by an up arrow) is antiferromagnetically coupled to the first continuous layer128, and the first continuous layer128is antiferromagnetically coupled to the multiple granular columns112(with a magnetization represented by an up arrow, matching the magnetization of the second continuous layer).

For clarity of illustration, the read/write head350is figuratively depicted interacting with only the first magnetic bit240. However, it is understood that the read/write head350may be relatively much larger than the first magnetic bit240, and the magnetic head350may simultaneously interact with many magnetic grains in adjacent bits.

Referring now toFIGS. 4, 5, 6, and 7, the interaction of the layers of the first bit240magnetically responding in sequential order to a write operation are shown according to one aspect of the present embodiments. At the beginning of the write operation (seeFIG. 4) and before a reversing magnetic field is turned on from a read/write head (not shown) the second continuous layer132may have, for example, a magnetization indicated by the up arrow.

As previously discussed, the second continuous layer132is antiferromagnetically coupled to the first continuous layer128, with the second AFC spacer layer130in-between. Due to the antiferromagnetic coupling, the first continuous layer128has a magnetization which is opposite to the second continuous layer132, and indicated by the down arrow.

In addition, the first continuous layer128is antiferromagnetically coupled to the multiple granular columns112, with the first AFC spacer layer126in-between. Due to the antiferromagnetic coupling, the multiple granular columns112have a magnetization which is opposite to the first continuous layer128, and indicated by the up arrows.

In response to a reversing magnetic field from a read/write head (not shown), the second continuous layer132changes magnetization orientation. In the present example, the magnetization of the second continuous layer132switches (seeFIG. 5), as indicated by the black down arrow. In response to the switching of the magnetization of the second continuous layer132, the magnetization of the first continuous layer128switches (seeFIG. 6), as indicated by the black up arrow. This is due to the AFC coupling between the two layers and that this coupling strength overcomes the writer field. In addition, in response to the switching of the magnetization of the first continuous layer128and the writer reversing field, the magnetizations of the multiple granular columns112switch (seeFIG. 7), as indicated by the black down arrows. As a result, the whole bit is reversed in a cascading fashion or domino effect.

Referring now toFIG. 8, a figurative representation of a profile of a magnetic writing field860interacting with a first track862, a second track864, and a third track866is shown according to one aspect of the present embodiments. Each of the tracks (862,864,866) include a number of bits868, and each of the bits868include a number of grains870. For clarity of illustration, the bits868in the tracks (862,864,866) are figuratively illustrated using equal rectangles. It is understood that in various embodiments, the size and shape of the bits868may be different between bits in the same track or different tracks. In addition, for clarity of illustration the grains870within separate bits868are figuratively illustrated using different shapes. In addition, the grains870are only illustrated in one bit per track, however, it is understood that the grains870are present in numerous bits per track.

When recording information to a disk, the grains870within one of the bits868are uniformly magnetically oriented with the magnetization orientation either pointing up (out of the surface ofFIG. 8) or pointing down (into the surface ofFIG. 8). Thus, information can be stored to and read back from each bit by reading/writing the uniform magnetization of the grains870within the bits868. As such, different bits have a positive or negative magnetization, that is used to store information on a disk.

However the magnetic writing field860can overlap adjacent tracks, thereby creating adjacent track interference. For example, the magnetic writing field860may be writing to second track864. While writing to the second track864, the magnetic writing field860may overlap a portion of the first track862and a portion of the third track866. As a result of the overlap, a portion of the bits868in the first track862and the third track866are exposed to the magnetic writing field860.

Although the magnetic writing field860is weaker in the overlapped regions, the grains870within the overlapped regions of the bits868have an increased likelihood of having their magnetization switched. Thus, the grains in the bits868in the first track862and the third track866may be undesirably affected (e.g. written) by the writer field during the writing process of writing the grains870in the second track864. If enough of the grains870within the bit868include undesired magnetizations, the disk drive may not be able to interpret the intended magnetization of the bit868, thereby losing information.

Due to AFC coupling between the first and second continuous layers, the embodiments presented herein unexpectedly reduce adjacent track interference, by increasing the robustness (e.g. resistance to erasure) of adjacent tracks, thereby reducing the likelihood that the bits868in adjacent tracks (e.g. the first track862and the third track866) will be affected by overlapping magnetic write fields (e.g. during write operations to the second track864). In addition, the embodiments presented herein unexpectedly reduce spontaneous fluctuation of the grains870, for example caused by thermal fluctuations. As a result of reducing adjacent track interference, tracks in various embodiments may be packed closer together, thereby increasing the cross-track density. By increasing the cross-track density, more information may be stored in the same area of a disk drive.

Referring now toFIG. 9, a perpendicular magnetic recording media900with antiferromagnetically coupled layers and ferromagnetically coupled layers is shown according to one aspect of the present embodiments. The magnetic recording media900is similar to the media described inFIG. 1from the substrate up to the granular columns. Thus, a substrate902is provided. Overlying the substrate902is a SUL904. Overlying the SUL904is a seed layer906. Overlying the seed layer906is a first intermediate layer908. A second intermediate layer910overlies the first intermediate layer908. A third intermediate layer911overlies the second intermediate layer910. Overlying the third intermediate layer911are multiple granular columns912. Boundaries914segregate the granular columns912.

In some embodiments each of the granular columns912may include a first magnetic layer916overlying the third intermediate layer911, a first break layer918overlying the first magnetic layer916, a second magnetic layer920overlying the first break layer918, a second break layer922overlying the second magnetic layer920, and a third magnetic layer924overlying the second break layer922. In various embodiments, first magnetic layer916, second magnetic layer920, and third magnetic layer924are ferromagnetically coupled through the corresponding first break layer918and the second break layer922. In various embodiments, the first break layer918and the second break layer922are non-magnetic spacer layers.

UnlikeFIG. 1, the magnetic recording media900includes a third break layer927overlying the multiple granular columns912, and a first continuous layer928overlying the third break layer927. The third break layer927is illustrated as continuous, however in various embodiments the third break layer927may be either granular or continuous. The third break layer927may be 0-20 Å thick, and could be weak magnetic or non-magnetic. The third break layer may include materials, such as Co, Cr, Pt, Ru, B, SiO2, TiO2, or other oxides or alloys. The material and thickness of the third break layer927are selected to induce ferromagnetic coupling between the first continuous layer928and the third magnetic layer924of the multiple granular columns912. In various embodiments, the third break layer927is a non-magnetic spacer layer.

A first non-magnetic AFC spacer layer926overlies the first continuous layer928. In various embodiments the first AFC spacer layer926is continuous and may include Ru. The first AFC spacer layer926induces antiferromagnetic coupling between the first continuous layer928to a second continuous layer932, overlying the first AFC spacer layer926.

A second non-magnetic AFC spacer layer930overlies the second continuous layer932. In various embodiments the second AFC spacer layer930is continuous and may include Ru. The second AFC spacer layer930induces antiferromagnetic coupling between the second continuous layer932to a third continuous layer933, overlying the second AFC spacer layer930. In some embodiments, the AFC spacer layer930may be sandwiched between two additional continuous layers (not shown) with high magnetization. The two additional continuous layers may include, for example, Co, CoCr, Co—Pt, Co—Cr—Pt alloys, or Co—Cr—Pt—B, and the two additional continuous layers may include other dopants of transition metals. Furthermore, the two additional continuous layers may be the same or different compositions. In some embodiments, the magnetization of the two additional continuous layers may be higher than the two coupled layers (e.g. the second continuous layer932to a third continuous layer933). It is understood that the two additional continuous sandwiching layers may be applied to all of the AFC spacers described herein (e.g. the first AFC spacer layer126and the second AFC spacer layer130).

In the present embodiment, the first continuous layer928is a bottom continuous layer with respect to the second continuous layer932which is a middle continuous layer. In addition, the third continuous layer933is a top continuous layer with respect to the second continuous layer932. In various embodiments, the first continuous layer928, the second continuous layer932, and the third continuous layer933may include Co—Pt alloys. In some embodiments, the Pt atomic percentage may be in the range of 0-50%. The first continuous layer928, the second continuous layer932, and the third continuous layer933may also include multiple other elements as dopants or alloying compounds, or even a small amount of oxides, such as SiO2, TiO2, B2O3, etc. In various embodiments the multiple other elements may be transition metals with an atomic percentage of 0-30%. In different embodiments, the first continuous layer928, the second continuous layer932, and the third continuous layer933may be the same material or different materials.

Referring now toFIG. 10, the relative magnetizations of the perpendicular magnetic recording media900are shown according to one aspect of the present embodiments. The multiple granular columns912and the first continuous layer928are ferromagnetically coupled and share the same magnetization, represented by the up arrows. The second continuous layer932is antiferromagnetically coupled to the first continuous layer928and has an oppose magnetization to the first continuous layer928, represented by the down arrow. The third continuous layer933is antiferromagnetically coupled to the second continuous layer932and has an opposite magnetization to the second continuous layer932, represented by the up arrow.

While the embodiments have been described and/or illustrated by means of particular examples, and while these embodiments and/or examples have been described in considerable detail, it is not the intention of the Applicants to restrict or in any way limit the scope of the embodiments to such detail. Additional adaptations and/or modifications of the embodiments may readily appear to persons having ordinary skill in the art to which the embodiments pertain, and, in its broader aspects, the embodiments may encompass these adaptations and/or modifications. Accordingly, departures may be made from the foregoing embodiments and/or examples without departing from the scope of the concepts described herein. The implementations described above and other implementations are within the scope of the following claims.