Patent Application
20230005503
The disclosure relates, in some aspects, to magnetic recording media for use with heat-assisted magnetic recording (HAMR), and more particularly, to HAMR media with a magnesium trapping layer to reduce magnesium migration to a nearby slider.
Magnetic storage systems, such as a hard disk drive (HDD), are utilized in a wide variety of devices in both stationary and mobile computing environments. Examples of devices that incorporate magnetic storage systems include desktop computers, portable notebook computers, portable hard disk drives, digital versatile disc (DVD) players, high definition television (HDTV) receivers, vehicle control systems, cellular or mobile telephones, television set top boxes, digital cameras, digital video cameras, video game consoles, and portable media players.
A typical disk drive includes magnetic storage media in the form of one or more fiat disks. The disks are generally formed of two main substances, namely, a substrate material that gives it structure and rigidity, and a magnetic media coating that holds the magnetic impulses or moments that represent data in a recording layer within the coating. The typical disk drive also includes a read head and a write head, generally in the form of a magnetic transducer which can sense and/or change the magnetic fields stored on the recording layer of the disks.
Energy/Heat Assisted Magnetic Recording (EAMR/HAMR) systems can increase the areal density of information recorded magnetically on various magnetic media. To achieve higher areal density for magnetic storage, smaller magnetic grain size (e.g., less than 6 nm) media may be required. In HAMR, high temperatures are applied to the media during writing to facilitate recording to small grains. However, the use of these high temperatures can present operational challenges and undesirable effects such as reliability issues in the HAMR components, including the media and head/slider.
The following presents a simplified summary of some aspects of the disclosure to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present various concepts of some aspects of the disclosure in a simplified form as a prelude to the more detailed description that is presented later.
In one embodiment, a medium configured for heat-assisted magnetic recording (HAMR) includes a substrate, a seed layer on the substrate and comprising MgO, a magnetic recording layer on the seed layer, and a Mg trapping layer on the substrate. The Mg trapping layer is configured to mitigate Mg migration from the seed layer to a surface of the HAMR medium above the magnetic recording layer. The Mg trapping layer comprises an oxide selected from the group consisting of TiO, TiO2, SiO, BaO, HfO, ZrO, MgTiO, MgTiO2, MgSiO, MgBaO, MgHfO, MgZrO, and combinations thereof.
In one embodiment, a heat-assisted magnetic recording (HAMR) medium includes a substrate, a seed layer on the substrate and comprising MgO, a magnetic recording layer on the seed layer, and a Mg trapping layer on the substrate. The Mg trapping layer is configured to mitigate Mg migration from the seed layer to a surface of the HAMR medium above the magnetic recording layer. The Mg trapping layer comprises a first compound having a first bond dissociation energy that is lower than a second bond dissociation energy of SiO2, and the first compound comprises less than 90 atomic percent of Mg.
In one embodiment, a method for manufacturing a heat-assisted magnetic recording (HAMR) medium is disclosed. The method includes: providing a substrate; providing a seed layer on the substrate, the seed layer comprising MgO; providing a magnetic recording layer on the seed layer; and providing a Mg trapping layer on the substrate, the Mg trapping layer configured to mitigate Mg migration from the seed layer to a surface of the HAMR medium above the magnetic recording layer. The Mg trapping layer comprises an oxide selected from the group consisting of TiO, TiO2, SiO, BaO, HfO, ZrO, MgTiO, MgTiO2, MgSiO, MgBaO, MgHfO, MgZrO, and combinations thereof.
In one embodiment, a method for manufacturing a heat-assisted magnetic recording (HAMR) medium is disclosed. The method includes: providing a substrate; providing a seed layer on the substrate, the seed layer comprising MgO; providing a magnetic recording layer on the seed layer; and providing a Mg trapping layer on the substrate, the Mg trapping layer configured to mitigate Mg migration from the seed layer to a surface of the HAMR medium above the magnetic recording layer. The Mg trapping layer comprises a first compound having a first bond dissociation energy that is lower than a second bond dissociation energy of SiO2, and the first compound comprises less than 90 percent of Mg.
These and other aspects of the disclosure will become more fully understood upon a review of the detailed description, which follows. Other aspects, features, and implementations of the disclosure will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific implementations of the disclosure in conjunction with the accompanying figures. While features of the disclosure may be discussed relative to certain implementations and figures below, all implementations of the disclosure can include one or more of the advantageous features discussed herein. In other words, while one or more implementations may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various implementations of the disclosure discussed herein. In similar fashion, while certain implementations may be discussed below as device, system, or method implementations, it should be understood that such implementations can be implemented in various devices, systems, and methods,
A more particular description is included below with reference to specific aspects illustrated in the appended drawings. Understanding that these drawings depict only certain aspects of the disclosure and are not therefore to be considered to be limiting of its scope, the disclosure is described and explained with additional specificity and detail through the use of the accompanying drawings, in which:
In the following detailed description, reference is made to the accompanying drawings, which form a part thereof. In addition to the illustrative aspects, aspects, and features described above, further aspects, aspects, and features will become apparent by reference to the drawings and the following detailed description. The description of elements in each figure may refer to elements of proceeding figures. Like numbers may refer to like elements in the figures, including alternate aspects of like elements.
The disclosure relates in some aspects to various apparatuses, systems, methods, and media for providing heat-assisted magnetic recording (HAMR) media that can improve the reliability of a near field transducer (NFT) used in a slider of a HAMR disk drive. In a HAMR disk drive, a laser source and an optical waveguide with a NFT (typically implemented on or in a slider) are used to generate localized heating in the media while a writing element or writer writes data to the media.
In some aspects, magnesium (Mg), often in the form of MgO, may be used in a seed layer of a HAMR medium or disk. However, Mg atoms or ions can dissociate from the seed layer and migrate to the disk surface, and further to the slider/head positioned just above the disk surface. The migrated Mg on the disk surface and on the slider may cause damage (e.g., severe damage) to the NFT that is within the slider disposed just above the disk. The Mg on the disk surface or on the slider can react with Si or Si compound (e.g., SiO2 (quartz)) that forms the cladding for the NFT and adversely affects the NFT. For example, the migrated Mg can react with NFT Si and form a SiMgO compound. The SiMgO compound has a lower thermal conductivity than Si or Si compound (e.g., quartz). Thermal stress can accumulate on the NFT because of the new compound has a lower thermal conductivity, and excess thermal stress (e.g., heat) can damage the NFT structure. Furthermore, SiMgO compounds (e.g., talc) can have a layered mineral structure. Thus, this layered SiMgO substance on the NFT can easily break off from the NFT during HDD operation and cause HAMR disk failure. Therefore, improving the reliability of the NFT can improve the lifespan of a HAMR disk drive.
In operation, the laser 114 is configured to generate and direct light energy to a. waveguide (e.g., along the dashed line) in the slider which directs the light to a near field transducer (NFT) 122 near the air bearing surface (e.g., bottom surface) 108c of the slider 108. Upon receiving the light from the laser 114 via the waveguide, the NFT 122 generates localized heat energy that heats a portion of the media 102 within or near the write element 108a, and near the read element 108b. The anticipated recording temperature is in the range of about 350° C. to 400° C. In the aspect illustrated in
In some aspects, a HAMR medium can include an underlayer (e.g., a MgO seed layer) for growing one or more magnetic recording layers (e.g., FePt magnetic recording layers). However, as described above, Mg may migrate (dissociate) from the seed layer and escape from a surface of the HAMR medium during disk drive operations. The escaped Mg can have an adverse and unexpected effect in a HAMR HDD. For example, the dissociated Mg can adversely affect a head disk interface (e.g., NFT in a slider) when the Mg reacts with a Si compound (e.g., SiO2) on the NFT. The Mg escaped from the HAMR medium can break the Si—O bond in SiO2 at the NFT, and forms MgO or SiMgO that can peel off from the NFT.
Some aspects of the disclosure provide a HAMR medium configured to mitigate Mg migration so as to reduce the quantity of dissociated Mg available to react with the SiO2 of an NFT. To that end, the HAMR medium may include a Mg trapping layer to reduce Mg migration from a seed layer. In some aspects, the Mg trapping layer includes a substance or material (e.g., an oxide compound) that can react with the dissociated Mg. The Mg trapping substance or material may be selected to have a bond dissociation energy lower than that of the Si—O bond in SiO2 of the NFT; therefore, the dissociated Mg reacts with the Mg trapping substance before it can escape from the HAMR medium to react with the SiO2 of the NFT. The bond dissociation energy of the Si—O bond in SiO2 is about 798 kJ/mol. Therefore, the selected Mg trapping substance or material has a bond dissociation energy lower than 798 kJ/mol. In other words, the Mg trapping layer can work as an Mg absorbent. During laser irradiation of a portion of a HAMR medium (e.g., for writing), Mg can diffuse from a MgO seed layer. The diffused Mg ions or atoms can go above and below the MgO seed layer. Some Mg can migrate to the disk surface. The Mg trapping layer can trap or absorb dissociated Mg before it can reach and escape from the disk surface. Some examples of suitable Mg trapping compound or material are TiO, TiO2, SiO, BaO, HfO, ZrO, MgTiO, MgTiO2, MgSiO, MgBaO, MgHfO, and MgZrO. The bond dissociation energy of some exemplary oxides are shown in Table 1 below.
In some aspects, the substrate 302 may be made of one or more materials such as an Al alloy, NiP plated Al, glass, glass ceramic, and/or combinations thereof. In some aspects, the heat sink layer 304 can be made of one or more materials such as Ag, Al, Au, Cu, Cr, Mo, Ru, W, CuZr, MoCu, AgPd, CrRu, CrV, CrW, CrMo, CrNd, NiAl, NiTa, combinations thereof, and/or other suitable materials known in the art. In some aspects, the MgO seed layer 306 may be made of MgO or other suitable materials known in the art. In one embodiment, the MgO seed layer 306 has a certain lattice structure that determines or limits a lattice structure of a layer (e.g., Mg trapping layer 308) grown/deposited on the MgO seed layer 306.
In some aspects, the Mg trapping layer 308 may be made of a Mg trapping compound, for example, TiO, SiO, BaO, HfO, ZrO, MgTiO, MgTiO2, MgSiO, MgBaO, MgHfO, MgZrO, or combinations thereof. The Mg trapping compound can react with the Mg ions or atoms dissociated from the MgO seed layer 306. The Mg trapping compound may be selected to have a bond dissociation energy lower than that of the Si—O bond in SiO2 of the NFT; therefore, the dissociated Mg may react with the Mg trapping compound before it can escape from the HAMR medium to react with the SiO2 of the NFT. In one embodiment, the Mg trapping compound has a bond dissociation energy lower than about 798 kJ/mol. In some aspects, the Mg trapping layer 308 may have a thickness that can facilitate coherent growth with a lattice structure substantially matching the MgO seed layer 306. Therefore, when the MRL 310 is grown on the Mg trapping layer 308, the lattice mismatch between the MRL 310 and the MgO seed layer can be reduced or minimized. For example, the MgO seed layer 306 may have a lattice constant of 4.2 Angstrom.
In one embodiment, the Mg trapping layer 308 may include a Mg compound (e.g., MgTiO, MgTiO2, MgSiO, MgBaO, MgHfO, MgZrO) that contains less than 90 atomic percent Mg (e.g., less than about 90 atomic percent). For example, the Mg compound may include Mg(x)A(100-x)O and/or Mg(x)A(100-x)O2, where A can be Ti, Si, Ba, Hf, and/or Zr, and X is atomic percent in the range of 0%≤90%. In one aspect, MgNiO, depending on a concentration of Mg contained therein, may be a suitable Mg trapping compound. In one specific example, MgNiO, with Mg concentration at 90 atomic percent or higher, may not be a suitable Mg trapping compound for use in the Mg trapping layer 308 even if MgNiO may have a bond dissociation energy lower than about 798 kJ/mol. While not bound by any particular theory, it is believed that the high concentration of Mg contained in this MgNiO (e.g., higher than 90 percent) causes the MgNiO layer to be ineffective (or largely ineffective) in trapping Mg, at least as compared to the other materials disclosed above as being suitable Mg trapping layer compounds. Possibly the high concentration of Mg in the MgNiO prevents or inhibits the disassociated Mg ions/atoms from bonding with the NiO within the MgNiO compound.
In some aspects, the MRL 310 may be made of FePt or an alloy selected from FePtX, where X is a material selected from Cu, Ni, and combinations thereof. In some aspects, the MRL 310 may be made of a CoPt alloy. In some aspects, the capping layer 312 may be made of Co, Pt, or Pd. In one example, the capping layer 312 can be a bi-layer structure having a top layer including Co and a bottom layer including Pt or Pd. In addition to the Co/Pt and Co/Pd combinations of the top layer and the bottom layer, specific combinations of the top layer materials and the bottom layer materials may include, for example, Co/Au, Co/Ag, Co/Al, Co/Cu, Co/Ir, Co/Mo, Co/Ni, Co/Os, Co/Ru, Co/Ti, Co/V, Fe/Ag, Fe/Au, Fe/Cu, Fe/Mo, Fe/Pd, Ni/Au, Ni/Cu, Ni/Mo, Ni/Pd, Ni/Re, etc. In additional examples, top layer materials and bottom layer materials include any combination of Pt and Pd (e.g., alloys), or any of the following elements, alone or in combination: Au, Ag, Al, Cu, Ir, Mo, Ni, Os, Ru, Ti, V, Fe, Re, and the like. In some aspects, the overcoat layer 314 may be made of carbon. In one aspect, the lubricant layer 316 is made of a polymer-based lubricant.
In some aspects, the MgO seed layer and the Mg trapping layer of the HAMR medium 300/400 can be combined or manufactured as a single layer.
In this example, placing the Mg trapping layer 510 on the MRL 508 allows the MRL 508 to be formed directly on the MgO seed layer 506 such that it is easier to match the lattice structure of the MRL 508 with that of the MgO seed layer 506. This is in contrast to the HAMR medium 300 of
The terms “above,” “below,' on,” and “between” as used herein refer to a relative position of one layer with respect to other layers. As such, one layer deposited or disposed on, above, or below another layer may be directly in contact with the other layer or may have one or more intervening layers. Moreover, one layer deposited or disposed between layers may be directly in contact with the layers or may have one or more intervening layers.
In one aspect, the Mg trapping layer can include an oxide selected from the group consisting of TiO, TiO2, SiO, BaO, HfO, ZrO, MgTiO, MgTiO2, MgSiO, MgBaO, MgHfO, MgZrO, or combinations thereof. In one aspect, the Mg trapping layer can include a first compound having a first bond dissociation energy that is lower than a second bond dissociation energy of a compound included in a NFT of a slider (e.g., SiO2) for writing data to the HAMR medium. For example, the first compound may have a bond dissociation energy that is lower than 798 kJ/mol. In one aspect, the first compound can include Mg at less than 90 atomic percent.
In one aspect, the process can perform the sequence of actions in a different order. In another aspect, the process can skip one or more of the actions. In other aspects, one or more of the actions are performed simultaneously. In some aspects, additional actions can be performed.
In several aspects, the deposition of such layers can be performed using a variety of deposition sub-processes, including, but not limited to physical vapor deposition (PVD), sputter deposition and ion beam deposition, and chemical vapor deposition (CVD) including plasma enhanced chemical vapor deposition (PECVD), low pressure chemical vapor deposition (LPCVD) and atomic layer chemical vapor deposition (ALCVD). In other aspects, other suitable deposition techniques known in the art may also be used.
The examples set forth herein are provided to illustrate certain concepts of the disclosure. The apparatuses, devices, or components illustrated above may be configured to perform one or more of the methods, features, or steps described herein. Those of ordinary skill in the art will comprehend that these are merely illustrative in nature, and other examples may fall within the scope of the disclosure and the appended claims. Based on the teachings herein those skilled in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein.
Aspects of the present disclosure have been described above with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, systems, and computer program products according to aspects of the disclosure. It will be understood that each block of the schematic flowchart diagrams and/or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and/or schematic block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a computer or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor or other programmable data processing apparatus, create means for implementing the functions and/or acts specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.
The subject matter described herein may be implemented in hardware, software, firmware, or any combination thereof. As such, the terms “function,” “module,” and the like as used herein may refer to hardware, which may also include software and/or firmware components, for implementing the feature being described. In one example implementation, the subject matter described herein may be implemented using a computer readable medium having stored thereon computer executable instructions that when executed by a computer (e.g., a processor) control the computer to perform the functionality described herein. Examples of computer-readable media suitable for implementing the subject matter described herein include non-transitory computer-readable media, such as disk memory devices, chip memory devices, programmable logic devices, and application specific integrated circuits. In addition, a computer readable medium that implements the subject matter described herein may be located on a single device or computing platform or may be distributed across multiple devices or computing platforms.
It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures, For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated figures. Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding aspects. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted aspect.
The various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and sub-combinations are intended to fall within the scope of this disclosure. In addition, certain method, event, state or process blocks may be omitted in some implementations. The methods and processes described herein are also not limited to any particular sequence, and the blocks or states relating thereto can be performed in other sequences that are appropriate. For example, described tasks or events may be performed in an order other than that specifically disclosed, or multiple may be combined in a single block or state. The example tasks or events may be performed in serial, in parallel, or in some other suitable manner. Tasks or events may be added to or removed from the disclosed example aspects. The example systems and components described herein may be configured differently than described. For example, elements may be added to, removed from, or rearranged compared to the disclosed example aspects.
Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as“exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term “aspects” does not require that all aspects include the discussed feature, advantage or mode of operation.
While the above descriptions contain many specific aspects of the invention, these should not be construed as limitations on the scope of the invention, but rather as examples of specific aspects thereof. Accordingly, the scope of the invention should be determined not by the aspects illustrated, but by the appended claims and their equivalents. Moreover, reference throughout this specification to “one aspect,” “an aspect,” or similar language means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect of the present disclosure. Thus, appearances of the phrases “in one aspect,” “in an aspect,” and similar language throughout this specification may, but do not necessarily, all refer to the same aspect, but mean “one or more but not all aspects” unless expressly specified otherwise.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well (i.e., one or more), unless the context clearly indicates otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive anti/or mutually inclusive, unless expressly specified otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” “including,” “having,” an variations thereof when used herein mean “including but not limited to” unless expressly specified otherwise. That is, these terms may specify the presence of stated features, integers, steps, operations, elements, or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Moreover, it is understood that the word “or” has the same meaning as the Boolean operator “OR,” that is, it encompasses the possibilities of “either” and “both” and is not limited to “exclusive or” (“XOR”), unless expressly stated otherwise. It is also understood that the symbol “/” between two adjacent words has the same meaning as “or” unless expressly stated otherwise. Moreover, phrases such as “connected to,” “coupled to” or “in communication with” are not limited to direct connections unless expressly stated otherwise.
Any reference to an element herein using a designation such as “first,” “second,” and so forth does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements may be used there or that the first element must precede the second element in some manner. Also, unless stated otherwise a set of elements may include one or more elements. In addition, terminology of the form “at least one of a, b, or c” or “a, b, c, or any combination thereof” used in the description or the claims means “a or b or c or any combination of these elements.” For example, this terminology may include a, or b, or c, or a and b, or a and c, or a and b and c, or 2a, or 2b, or 2c, or 2a and b, and so on.
As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining, and the like. Also, “determining” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Also, “determining” may include resolving, selecting, choosing, establishing, and the like.
