Abstract: A patterned perpendicular magnetic recording medium, such as a disk for use in hard disk drives, has a flux channeling layer (FCL) located below the recording layer (RL) in each of the discrete data islands. The disk includes a substrate, a soft underlayer (SUL) of soft magnetically permeable material on the substrate, and a nonmagnetic exchange break layer (EBL) on the SUL. A nonmagnetic separation layer (SL) is located between the FCL and the RL in the islands. The FCL has an anisotropy field substantially lower than the anisotropy field of the RL, and a magnetization equal to or higher than the magnetization of the RL. The FCL is saturated at a much lower field than the RL and thus channels the magnetic flux from the write head through the island positions. The dipolar fields from the RL above the FCL polarize the magnetization of the FCL parallel to the magnetization direction of the RL in the absence of an external field, to thereby enhance the readback signal.

Abstract: A longitudinal magnetic recording medium comprising at least four magnetic layers including a substrate, a CoCrTa magnetic intermediate layer on the substrate, wherein the CoCrTa magnetic intermediate layer comprises Cr<16 at % and Ta<6 at %, a first CoCrPtB magnetic layer on the CoCrTa layer, wherein the first CoCrPtB magnetic layer comprises Cr: 10-14%, Pt: 4-8 at %, B: 6-10%, a second CoCrPtB magnetic layer on the first CoCrPtB magnetic layer, and a third CoCrPtB magnetic layer on the second CoCrPtB layer, wherein the third CoCrPtB magnetic layer comprises Cr: 12-16 at %, Pt: 12-16 at %, B: 10-14 at % and has <10 at % Cr than that in the second CoCrPtB magnetic layer is disclosed.

Abstract: A perpendicular recording medium having a perpendicular magnetic recording layer and a magnetically soft underlayer structure disposed beneath the recording layer. The soft underlayer structure includes at least first and second soft magnetic layers having different magnetic permeabilities to create a magnetic permeability gradient in the soft underlayer structure. One or more of the soft magnetic layers can be anti-parallel coupled. The soft underlayer structure of the present invention having a magnetic permeability gradient advantageously leads to reduced adjacent track erasure (ATE) while maintaining good overwrite (OW) properties.

Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium improved for fly ability, high in read signal quality, and capable of suppressing magnetic decay of recorded magnetization to be caused by stray fields. In one embodiment, a perpendicular recording layer is formed over a substrate with a soft magnetic underlayer therebetween, then an amorphous or nano-crystalline layer is formed between the substrate and the soft magnetic underlayer. The soft magnetic underlayer includes first and second amorphous soft magnetic layers, as well as a nonmagnetic layer formed between those first and second amorphous soft magnetic layers. The first and second amorphous soft magnetic layers are given uniaxial anisotropy in the radial direction of the substrate respectively and coupled with each other antiferromagnetically.

Abstract: Embodiments of the invention provide a perpendicular magnetic recording medium improved for fly ability, high in read signal quality, and capable of suppressing magnetic decay of recorded magnetization to be caused by stray fields. In one embodiment, a perpendicular recording layer is formed over a substrate with a soft magnetic underlayer therebetween, then an amorphous or nano-crystalline layer is formed between the substrate and the soft magnetic underlayer. The soft magnetic underlayer includes first and second amorphous soft magnetic layers, as well as a nonmagnetic layer formed between those first and second amorphous soft magnetic layers. The first and second amorphous soft magnetic layers are given uniaxial anisotropy in the radial direction of the substrate respectively and coupled with each other antiferromagnetically.

Abstract: A perpendicular magnetic recording medium, usable for either continuous or patterned media, has a recording layer structure (RLS) of first and second perpendicular magnetic layers (PM1, PM2) and an antiferromagnetically coupling (AFC) layer and a ferromagnetic switching layer (SWL) between PM1 and PM2. The magnetic recording system uses heat to assist in the reading and/or writing of data. The SWL is a Co/Ni multilayer with a Curie temperature (TC-SWL) less than the Curie temperatures of PM1 and PM2. At room temperature, there is ferromagnetic coupling between SWL and the upper ferromagnetic layer (PM2) so that the magnetizations of SWL and PM2 are parallel, and antiferromagnetic coupling between SWL and the lower ferromagnetic layer (PM1) across the AFC layer so that the magnetization of PM1 is aligned antiparallel to the magnetizations of SWL and PM2.

Abstract: A perpendicular magnetic recording medium adapted for high recording density and high data recording rate comprises a non-magnetic substrate having at least one surface with a layer stack formed thereon, the layer stack including a perpendicular recording layer containing a plurality of columnar-shaped magnetic grains extending perpendicularly to the substrate surface for a length, with a first end distal the surface and a second end proximal the surface, wherein each of the magnetic grains has: (1) a gradient of perpendicular magnetic anisotropy field Hk extending along its length between the first end and second ends; and (2) predetermined local exchange coupling strengths along the length.

Abstract: A perpendicular magnetic recording system and medium has a multilayered recording layer that includes an exchange-spring structure and a ferromagnetic lateral coupling layer (LCL). The exchange-spring structure is made up of two ferromagnetically exchange-coupled magnetic layers (MAG1 and MAG2), each with perpendicular magnetic anisotropy. MAG1 and MAG2 may have a coupling layer (CL) located between them that permits ferromagnetic exchange coupling of MAG1 with MAG2. The LCL is located either above or below MAG1 and in direct contact with MAG1 and mediates an effective intergranular exchange coupling in MAG1. The ferromagnetic alloy in the LCL has significantly greater intergranular exchange coupling than the ferromagnetic alloy in MAG1, which typically will include segregants such as oxides. The LCL is preferably free of oxides or other non-metallic segregants, which would tend to reduce intergranular exchange coupling in the LCL.

Abstract: The present invention relates to perpendicular magnetic recording media with improved signal-to-medium noise ratio (“SMNR”) and thermal stability, which media include a pair of vertically spaced-apart perpendicular ferromagnetic layers which are anti-ferromagnetically coupled (“AFC”) across a non-magnetic spacer layer. The invention is of particular utility in the fabrication of data/information storage and retrieval media, e.g., hard disks, having ultra-high areal recording/storage densities.

Abstract: Embodiments of the present invention provide a magnetic disk drive capable of allowing higher data transfer rates and higher recording densities. According to one embodiment, an upper magnetic core and lower magnetic core comprise a multi-layered magnetic film formed by alternately stacking a face-centered cubic (fcc) crystalline magnetic thin layer and a body-centered cubic (bcc) crystalline magnetic thin layer by plating. The plating bath is such that the temperature is about 30±1° C., pH is about 2.0?1.0 to 2.0+0.5, metal ion concentrations are about 5 to 25 (g/l) for Ni2+ and 5 to 15 (g/l) for Fe2+, saccharin sodium concentration is about 1.5±1.0 (g/l), sodium chloride concentration is about 25±5 (g/l), and boric acid concentration is about 25±5 (g/l). Since each layer's crystal structure is different from that of its adjacent lower layer, epitaxial growth is broken within each layer.

Abstract: A perpendicular magnetic recording medium, including a soft-magnetic backing layer; and a recording layer provided over the oft-magnetic backing layer. There is provided a magnetic flux slit layer between the soft-magnetic backing layer and the recording layer. The magnetic flux slit layer includes a soft-magnetic layer having a generally columnar structure generally isolated magnetically in an in-plane direction. The magnetic flux slit layer contains at least one selected from the group consisting of Co, Fe, Ni, a Co alloy, a Fe alloy, and a Ni alloy, as a major component, and the magnetic flux slit layer further contains any one selected from the group consisting of Ta, Cu, Pb, Cr, and Re.

Abstract: A perpendicular magnetic recording medium including a soft magnetic underlayer. The perpendicular magnetic recording medium includes: a lower structural body including an anti-ferromagnetic layer; a first soft magnetic underlayer, a non-magnetic layer, and a second soft magnetic underlayer sequentially formed on the anti-ferromagnetic layer, where the thickness ratio of the second soft magnetic underlayer to that of the first soft magnetic underlayer is designed to be within specific range; and a recording layer formed on the second soft magnetic underlayer. Therefore, noise generated on the soft magnetic underlayer due to external magnetic fields of a magnetic head and a voice coil motor can be reduced greatly.

Abstract: A perpendicular magnetic recording medium composed of a nonmagnetic substrate having a surface onto which are provided a plurality of layers including, in the order recited, a soft underlayer; a nonmagnetic coupling layer; a hard magnetic pinning layer which is antiferromagnetically coupled to the soft underlayer at ambient temperature via the nonmagnetic coupling layer and which has an axis of easy magnetization which extends in a direction which is perpendicular to that of the surface of the nonmagnetic substrate; a nonmagnetic intermediate layer; and a magnetic recording layer. Such a perpendicular magnetic recording medium has an improved medium performance, with reduced noise originating from the presence of the soft underlayer, and no erasure of recorded magnetization when influenced by an external magnetic field.

Abstract: A multilayered three-dimensional media having a plurality of magnetic sublayers, each of the magnetic sublayers being separated from one another by a non-magnetic layer. The plurality of magnetic sublayers can be a stack of one or more coupled Co/Pd or Co/Pt layers; a layer of Co—Cr alloys optionally containing TiO2, SiO2, C, Pt, and B; a stack of one or more Co—Cr—Pt/Pt layers; a stack of one or more Co—Cr—Pd/Pd layers; and/or a stack of one or more layers of Fe—Pt, Fe—Pd, Co—Pt, and Co—Pd materials in an L10 phase. The non-magnetic layers are Pd, Pt, Ti, Ta, Cu, Au, Ag, MgO, or/and ITO. In addition, a multilayered three-dimensional recording system is disclosed, which includes a three-dimensional media, the three-dimensional media includes a plurality of magnetic sublayers, wherein each magnetic sublayer is adapted for writing data to; and a recording head having a trailing edge, and wherein the trailing edge has a higher permeability than the recording head.

Abstract: A magnetic recording medium having a Au, Ag-containing magnetic layer having Co, Cr, Ag and Au; the magnetic recording layer having Co-containing magnetic grains surrounded by substantially nonmagnetic Cr-containing grain boundaries; wherein said Ag and said Au are substantially immiscible in the Co-containing magnetic grains is disclosed.

Abstract: A perpendicular magnetic recording medium includes: a nonmagnetic substrate; a soft magnetic backing layer formed above the nonmagnetic substrate; a nonmagnetic intermediate layer formed on the soft magnetic backing layer; and a magnetic recording layer formed on the nonmagnetic intermediate layer, the magnetic recording layer including a first ferromagnetic recording layer having perpendicular magnetic anisotropy, a coupling layer formed on the first ferromagnetic recording layer and made of Pd, Pt or alloy of Pd and Pt, and a second ferromagnetic recording layer formed on the coupling layer and having perpendicular magnetic anisotropy.

Abstract: A bit error rate is improved and, at the same time, an aging change due to thermal fluctuation is decreased. In one embodiment, a magnetic recording medium has first, second, third, and fourth magnetic layers stacked over the underlayer film on a substrate. The product (Brt2) of the residual magnetic flux density and film thickness of the second magnetic layer is smaller than the product (Brt3) of the residual magnetic flux density and film thickness of the third magnetic layer. The second magnetic layer has a thickness larger than that of the third magnetic layer and is anti-ferromagnetically coupled with the first magnetic layer by way of the first non-magnetic intermediate layer. The fourth magnetic layer is formed by way of a second non-magnetic intermediate layer above the third magnetic layer.

Abstract: Embodiments of the present invention help to provide an excellent perpendicular recording medium of high medium signal-to-noise (S/N) and with suppressed blurring in writing. According to one embodiment, a perpendicular recording layer is provided by way of a negative magnetic strain soft-magnetic underlayer above a substrate applied with texturing in the circumferential direction. The soft-magnetic underlayer has a first soft magnetic layer, a second soft magnetic layer and a nonmagnetic magnetic layer formed between the first soft magnetic layer and the second soft magnetic layer in which the first soft magnetic layer and the second soft magnetic layer are antiferromagnetically coupled to each other and the easy magnetization axis is directed in the radial direction.

Abstract: A thin film structure comprises a first layer including a first plurality of grains of magnetic material having a first intergranular exchange coupling, and a second layer positioned adjacent to the first layer and including a second plurality of grains of magnetic material having a second intergranular exchange coupling, wherein the second intergranular exchange coupling is larger than the first intergranular exchange coupling and wherein the Curie temperature of the first layer is greater than the Curie temperature of the second layer. A data storage system including the thin film structure is also provided.

Abstract: A magnetic recording medium having a first magnetic layer, a spacer layer, and a second magnetic layer, in this order, wherein the spacer layer includes a non-magnetic layer and a thickness of the spacer layer is selected to establish anti-ferromagnetic coupling between the first magnetic layer and the second magnetic layer, and a thickness of both the first and second magnetic layers are less than a critical thickness for formation of stripe domains in the magnetic layers is disclosed.

Abstract: An AFC magnetic recording medium having a three-layered ferromagnetic structure capable of reducing noises without deteriorating thermal stability is provided in order to achieve ultra-high recording density.

Abstract: A perpendicular magnetic recording medium has an “exchange-spring” type magnetic recording layer (RL) with an improved coupling layer (CL). The RL includes the first or lower ferromagnetic layer MAG1, sometimes called the “media” layer, the second or upper ferromagnetic layer MAG2, sometimes called the “exchange-spring” layer, and the intermediate CL that provides ferromagnetic exchange coupling between MAG1 and MAG2. The CL is formed of NiCr or RuCr based alloys, or CoCr or CoCrB alloys with high Cr and/or B content (Cr plus B>about 25 atomic percent), or RuCoCr alloys with low Co content (<about 65 atomic percent). For each CL composition there is a CL thickness range that provides the optimal interlayer exchange coupling between MAG1 and MAG2. The selected CL materials provide an exchange-type perpendicular magnetic recording medium with good magnetic performance, while the relatively high amount of Cr of the CL improves the corrosion resistance of the medium.

Abstract: A magnetic recording medium is provided with a first magnetic layer, a nonmagnetic coupling layer provided on the first magnetic layer, and a second magnetic layer provided on the nonmagnetic coupling layer. The first and second magnetic layers are exchange-coupled, and have magnetization directions which are mutually parallel in a state where no external magnetic field is applied thereto, and the first magnetic layer switches the magnetization direction thereof before the second magnetic layer in response to a recording magnetic field which switches the magnetization directions of the first and second magnetic layers.

Abstract: A disclosed perpendicular magnetic recording medium includes a substrate; a soft magnetic underlayer disposed on the substrate and having no remanent magnetization; and a ferromagnetic recording layer disposed on the soft magnetic underlayer. The soft magnetic underlayer includes at least three soft magnetic layers laid one above the other with a non-magnetic intermediate layer interposed between every two adjacent soft magnetic layers. Among the (at least) three soft magnetic layers, at least one pair of soft magnetic layers form ferromagnetic coupling. Among the (at least) three soft magnetic layers, at least one pair of soft magnetic layers form antiferromagnetic coupling.

Abstract: Embodiments of the present invention provide a perpendicular magnetic recording medium that reduces the noise of granular recording layers, obtains sufficient overwrite characteristic that suppresses an increase in the magnetic cluster size, and allows high-density recording. According to one embodiment, a perpendicular magnetic recording medium comprising substrate having thereon at least soft magnetic layer, nonmagnetic intermediate layer, a perpendicular recording layer and protective layer formed in that order. The perpendicular recording layer consists of three or more layers of first recording layer, a second recording layer, and a third recording layer from the side nearer to the substrate. The first recording layer and the second recording layer have a granular structure comprising a grain boundary of an oxide surrounding ferromagnetic crystal grains containing Co and Pt, and the third recording layer has a non-granular structure mainly comprising Co and not containing an oxide.

Abstract: A recording medium including a perpendicular magnetic recording layer and a laminated SUL formed on a substrate is provided. The SUL includes an antiferromagnetic layer interposed between laminated structures including a magnetic layer, a non-magnetic layer and a magnetic layer. The layers may each have a thickness of 20 nm or less and the layers below the antiferromagnetic layer may be thinner than the layers on the antiferromagnetic layer. The laminated structures formed on and below the antiferromagnetic layer have unidirectional magnetic anisotropies set in the opposite radial direction to each other by an exchange bias. As a result, media magnetic domain noise can be diminished.

Abstract: A disclosed magnetic recording medium includes a substrate; a soft magnetic backing layer disposed on the substrate; an intermediate layer disposed on the soft magnetic backing layer; a first recording layer disposed on the intermediate layer and having perpendicular magnetic anisotropy; an exchange-coupling-energy control layer disposed on the first recording layer and made of a granular material in which oxide is added to metal including ruthenium; and a second recording layer disposed on the exchange-coupling-energy control layer, having perpendicular magnetic anisotropy, and ferromagnetically coupled with the first recording layer via the exchange-coupling-energy control layer.

Abstract: A perpendicular magnetic recording medium includes a nonmagnetic substrate; a first underlayer provided on the nonmagnetic substrate; a first nonmagnetic intermediate layer provided on the first underlayer; a second underlayer provided on the first nonmagnetic intermediate layer; a second nonmagnetic intermediate layer provided on the second underlayer; and a magnetic recording layer provided on the second nonmagnetic intermediate layer, wherein the first underlayer comprises a soft magnetic material which has a face-centered cubic structure and which includes at least Ni and Fe, and wherein the second underlayer comprises a soft magnetic material which has a face-centered cubic structure and which includes at least Co.

Abstract: A magnetic recording medium and a magnetic recording apparatus for perpendicular magnetic recording. The recording medium includes a magnetically soft underlayer and a hard magnetic pinning layer having perpendicular anisotropy. The magnetically soft underlayer is substantially free of domain walls.

Abstract: A perpendicular magnetic recording system and medium has a multilayered recording layer that includes an exchange-spring structure and a ferromagnetic lateral coupling layer (LCL). The exchange-spring structure is made up of two ferromagnetically exchange-coupled magnetic layers (MAG1 and MAG2), each with perpendicular magnetic anisotropy. MAG1 and MAG2 are either in direct contact with one another or have a coupling layer (CL) located between them. The LCL is located in direct contact with MAG2 and mediates intergranular exchange coupling in MAG2. The ferromagnetic alloy in the LCL has significantly greater intergranular exchange coupling than the ferromagnetic alloy in MAG2, which typically will include segregants such as oxides. The LCL is preferably free of oxides or other segregants, which would tend to reduce intergranular exchange coupling in the LCL.

Abstract: A perpendicular magnetic recording disk has a soft magnetic underlayer (SUL) that has high corrosion resistance as well as high moment. The material of the SUL is an alloy comprising Co, Fe, X, and Y; where X is Ta or Nb, Y is Zr or Hf, and the combined amount of X and Y present in the alloy is between about 10 and 20 atomic percent. The atomic ratio of Co to Fe in the alloy is between about 90:10 to 10:90, preferably between about 25:75 and 35:65. The SUL may be a single-layer SUL or a multilayer SUL formed of multiple soft magnetic layers separated by an interlayer film or films.

Abstract: A perpendicular magnetic recording disk has an antiferromagnetically-coupled (AFC) recording layer (RL) comprised of lower and upper ferromagnetic layers, each having a hexagonal-close-packed (hcp) crystalline structure and perpendicular magnetic anisotropy, separated by an antiferromagnetically (AF) coupling layer, wherein the lower ferromagnetic layer (LFM) has substantially higher magnetic permeability than the upper ferromagnetic layer (UFM). The AFC RL is located on an actual exchange break layer (EBL) that separates the AFC RL from the disk's soft magnetic underlayer (SUL). The LFM functions as part of an “effective” exchange break layer (EBL) that also includes the actual EBL and the AF-coupling layer, thereby allowing the actual EBL to be made as thin as possible. The hcp LFM promotes the growth of the hcp UFM in the same way the actual EBL does so that its thickness contributes to the thickness necessary to grow the hcp UFM.

Abstract: A perpendicular magnetic recording system uses an exchange-spring type of perpendicular magnetic recording medium. The medium has a recording layer (RL) that includes a lower media layer (ML) and a multilayer exchange-spring layer (ESL) above the ML. The high anisotropy field (high-Hk) lower ML and the multilayer ESL are exchange-coupled across a coupling layer. The multilayer ESL has at least two ESLs separated by a coupling layer, with each of the ESLs having an Hk substantially less than the Hk of the ML. The exchange-spring structure with the multilayer ESL takes advantage of the fact that the write field magnitude and write field gradient vary as a function of distance from the write pole. The thicknesses and Hk values of each of the ESLs can be independently varied to optimize the overall recording performance of the medium.

Abstract: An embodiment of the invention is a layered magnetic thin film structure that uses antiferromagnetically coupled (AFC) magnetic layers where the top layer structure consists of an upper magnetic layer that is weakly ferromagnetically coupled via a nonmagnetic or weakly magnetic exchange coupling layer (interlayer) to a ferromagnetic exchange enhancing layer that is in turn, AF coupled to the lower ferromagnetic layer of the AFC structure. Preferred materials for the weak coupling layer include alloys of cobalt such as CoRu, CoBRu and CoCr in which the Co content is below the point at which the material would be ferromagnetic. A second embodiment of the invention is a laminated, AF-coupled media structure. In this structure the lower AFC layer that makes up the lower laminate layer includes: the middle magnetic layer, the weak ferromagnetic coupling layer, and the exchange enhancing layer.

Abstract: According to one embodiment, a perpendicular magnetic recording medium includes a substrate, soft magnetic underlying layer, nonmagnetic underlying layer, and perpendicular magnetic recording layer. The perpendicular magnetic recording layer has an array of magnetic structures each corresponding to 1 bit of recording information, and includes a crystalline hard magnetic recording layer having perpendicular magnetic anisotropy, and an amorphous soft magnetic recording layer. The hard and soft magnetic recording layers are coupled by exchange coupling.

Abstract: A perpendicular magnetic recording medium has an “exchange-spring” type magnetic recording layer (RL) formed of two ferromagnetic layers with substantially similar anisotropy fields that are ferromagnetically exchange-coupled by a nonmagnetic or weakly ferromagnetic coupling layer. Because the write head produces a larger magnetic field and larger field gradient at the upper portion of the RL, while the field strength decreases further inside the RL, the upper ferromagnetic layer can have a high anisotropy field. The high field and field gradient near the top of the RL, where the upper ferromagnetic layer is located, reverses the magnetization of the upper ferromagnetic layer, which then assists in the magnetization reversal of the lower ferromagnetic layer. Because both ferromagnetic layers in this exchange-spring type RL have a high anisotropy field, the thermal stability of the medium is not compromised. The medium shows improved writability, i.e.

Abstract: A magnetoresistive tunnel junction sensor having improved free layer stability, as well as improved free sensitivity. The free layer is constructed to have a low magnetic coercivity which improves free layer sensitivity. The free layer is also constructed to have a negative magnetostriction which improves free layer stability by preventing the free layer from having an easy axis that is oriented perpendicular to die air bearing surface.

Abstract: A longitudinal magnetic recording medium having a high medium S/N, with no problems in view of the overwrite characteristic, excellent in the bit error rate and sufficiently stable also to thermal fluctuations is provided. In one embodiment, a first underlayer, second underlayer, and a third underlayer are formed on a substrate and, further, a first magnetic layer, a spacer layer including Ru as a main ingredient, a second magnetic layer, and a third magnetic layer are formed in adjacent with each other in this order. The thickness of the second magnetic layer is made larger than the thickness of the third magnetic layer and the total for the concentrations of cobalt and platinum obtained in the second magnetic layer is not more than the total for the concentrations of cobalt and platinum contained in the third magnetic layer.

Abstract: The invention uses an upper and lower magnetic layer of a laminated magnetic layer structure that includes an AF spacer layer that results in weak antiferromagnetic coupling of the magnetic layers that is insufficient to cause either of the layers to switch so that the magnetic orientations of the two ferromagnetic layers remain parallel. An advantage of the invention is that the AF-coupling tends to anti-correlate the noise in the two layers. The weak AF coupling according to the invention is believed to act at the transition boundaries in the media to cause some of the noise domains to be oriented antiparallel and the noise to be less correlated than would be the case without the AF coupling and thereby to achieve improved SNR.

Abstract: Laminated magnetic recording medium with two Co-containing layers separated by a non-magnetic Ru-containing interlayer is stabilized by Ru-containing layer between the recording layers and Co-containing stabilization layers through anti-ferromagnetic coupling. The insertion of Co layer beneath Ru spacer has resulted in increased coupling, and further coupling enhancement is achieved by low pressure process of Co and Ru layers.

Abstract: A perpendicular magnetic recording medium includes a metamagnetic antiferromagnetically-coupled (AFC) layer between the recording layer (RL) and the soft magnetically permeable underlayer (SUL). The metamagnetic AFC layer has essentially no net magnetic moment in the absence of a magnetic field, but is highly ferromagnetic in the presence of a magnetic field above a threshold field. Thus the metamagnetic AFC layer does not contribute to the readback signal during reading, but channels the write field to the SUL during writing because the threshold field is selected to be below the write field. An exchange-break layer EBL is located between the metamagnetic AFC layer and the RL. The metamagnetic AFC layer contains films with a crystalline structure suitable as a growth template for the EBL and RL, so the metamagnetic AFC layer also functions as part of an “effective EBL”, thereby allowing the actual EBL to be made as thin as possible.

Abstract: A laminated film structure is disclosed comprising multiple ferromagnetic layers achieving improved data recording performance. A non-magnetic spacer layer is disposed between an upper ferromagnetic layer and an antiferromagnetic coupled (AFC) structure. The AFC structure is comprised of a ferromagnetic layer and an antiferromagnetic slave layer. The ferromagnetic layer in the AFC structure, referred to as lower ferromagnetic layer, may contain tantalum to promote chromium segregation at the grain boundaries to achieve magnetic decoupling of the grains with relatively thin boundaries, improving medium signal-to-noise ratio while maintaining good thermal stability of the medium. In some embodiments, the interlayer is a five-element alloy such as a CoCrPtBTa alloy.

Abstract: A perpendicular magnetic recording medium is disclosed that exhibits reduced media noise and enhanced thermal stability of recorded magnetization, and thus provides a medium of high recording density and excellent read-write performance. The perpendicular magnetic recording medium comprises a magnetic film on a nonmagnetic substrate. The magnetic film is a multilayered lamination film composed of alternately laminated first magnetic layers of cobalt and second magnetic layers of palladium, the second magnetic layers containing SiO2. By setting a ratio of Ku2 to Ku to a value not smaller than a specified value, the compatibility between the ease of writing-in to the perpendicular magnetic recording medium by a head and the thermal stability of recorded magnetization is more improved.

Abstract: A perpendicular magnetic recording medium, such as a perpendicular magnetic recording disk, has a magnetic “torque” layer (MTL) that exerts a magnetic torque onto the perpendicular magnetic recording layer (RL) in the presence of the applied perpendicular write field. The MTL thus acts as a write assist layer in reversing the magnetization of the RL. A coupling layer (CL) is located between the MTL and the RL and provides the appropriate ferromagnetic coupling strength between the MTL and the RL.

Abstract: A magnetic recording medium having a substrate, an interlayer and a magnetic layer, the interlayer having at least a first intermediary layer, a second intermediary layer and a third intermediary layer, wherein the first intermediary layer or the third intermediary layer is non-magnetic or magnetic and the second intermediary layer has a hexagonal close pack crystal structure and a property of providing RKKY coupling between the first intermediary layer and the third intermediary layer when the first intermediary layer and the second intermediary layer are magnetic layers is disclosed.

Abstract: A laminated perpendicular magnetic recording medium has two recording layers (RL1 and RL2) that are separated and magnetically decoupled by a nonmagnetic spacer layer (SL). The SL has a thickness and composition to assure there is no antiferromagnetic or ferromagnetic coupling between RL1 and RL2. Thus in the presence of the write field, RL1 and RL2 respond independently and become oriented with the direction of the write field. Each RL is an “exchange-spring” type magnetic recording layer formed of two ferromagnetic layers (MAG1 and MAG2) that have substantially perpendicular magnetic anisotropy and are ferromagnetically exchange-coupled by a nonmagnetic or weakly ferromagnetic coupling layer (CL). The medium takes advantage of lamination to attain higher signal-to-noise ratio (SNR) yet has improved writability as a result of each RL being an exchange-spring type RL.

Abstract: Embodiments of the present invention help to provide a perpendicular magnetic recording medium in which a perpendicular magnetic recording layer is formed via a soft magnetic under-layer on a disk substrate, whereby the error rate is reduced and high density recording is enabled. According to one embodiment, the disk substrate is textured so that the center line average height (Ra) is from 0.05 nm to 0.2 nm, in which the soft magnetic under-layer is amorphous and has a film thickness from 2.5 nm to 10 nm, and the magnetic field for saturation (Hs) of the perpendicular magnetic recording layer is 7 kOe or less.

Abstract: A method and apparatus for improving the signal-to-noise ratio in a longitudinal recording media is disclosed. The apparatus includes a first recording layer of the longitudinal recording media residing at the top of a recording media structure. The first recording layer includes an upper sublayer comprised of a CoPtCrB-based alloy material. The first recording layer also includes a lower sublayer comprised of a CoPtCrB-based alloy material and a middle sublayer comprised of a CoCrB-alloy. The middle sublayer is coupled to the upper sublayer and to the lower sublayer and is substantially thinner than the upper sublayer and the lower sublayer.

Abstract: A perpendicular magnetic recording medium has an “exchange-spring” type magnetic recording layer (RL) with an improved coupling layer (CL). The RL includes the first or lower ferromagnetic layer MAG1, sometimes called the “media” layer, the second or upper ferromagnetic layer MAG2, sometimes called the “exchange-spring” layer, and the intermediate CL that provides ferromagnetic exchange coupling between MAG1 and MAG2. The CL is formed of NiCr or RuCr based alloys, or CoCr or CoCrB alloys with high Cr and/or B content (Cr plus B>about 25 atomic percent), or RuCoCr alloys with low Co content (<about 65 atomic percent). For each CL composition there is a CL thickness range that provides the optimal interlayer exchange coupling between MAG1 and MAG2. The selected CL materials provide an exchange-type perpendicular magnetic recording medium with good magnetic performance, while the relatively high amount of Cr of the CL improves the corrosion resistance of the medium.

Abstract: This application discloses a magnetoresistive multilayer film having the structure where an antiferromagnetic layer, a pinned-magnetization layer, a non-magnetic spacer layer and a free-magnetization layer are laminated in this order. An opposite-side layer is provided on the side of the antiferromagnetic layer opposite to the pined-magnetization layer. The opposite-side layer has components of nickel and chromium. An atomic numeral ratio of chromium in the opposite-side layer is preferably not less than 41% and not more than 70%, more preferably not less than 43%.