摘要:
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. Because the LCL grain boundaries overlay the boundaries of the generally segregated and decoupled grains of MAG1, and the LCL and MAG1 grains are strongly coupled perpendicularly, the LCL introduces an effective intergranular exchange coupling in the MAG1.
摘要:
A patterned perpendicular magnetic recording medium has discrete magnetic islands, each of which has a recording layer (RL) structure that comprises two exchange-coupled ferromagnetic layers. The RL structure may be an “exchange-spring” RL structure with an upper ferromagnetic layer (MAG2), sometimes called the exchange-spring layer (ESL), ferromagnetically coupled to a lower ferromagnetic layer (MAG1), sometimes called the media layer (ML). The RL structure may also include a coupling layer (CL) between MAG1 and MAG2 that permits ferromagnetic coupling. The interlayer exchange coupling between MAG1 and MAG2 may be optimized, in part, by adjusting the materials and thickness of the CL. The RL structure may also include a ferromagnetic lateral coupling layer (LCL) that is in contact with at least one of MAG1 and MAG2 for mediating intergranular exchange coupling in the ferromagnetic layer or layers with which it is in contact (MAG2 or MAG1). The ferromagnetic alloy in the LCL has significantly greater intergranular exchange coupling than the ferromagnetic alloy with which it is in contact (MAG2 or MAG1).
摘要:
A patterned perpendicular magnetic recording medium has discrete magnetic islands, each of which has a recording layer (RL) structure that comprises two exchange-coupled ferromagnetic layers. The RL structure may be an “exchange-spring” RL structure with an upper ferromagnetic layer (MAG2), sometimes called the exchange-spring layer (ESL), ferromagnetically coupled to a lower ferromagnetic layer (MAG1), sometimes called the media layer (ML). The RL structure may also include a coupling layer (CL) between MAG1 and MAG2 that permits ferromagnetic coupling. The interlayer exchange coupling between MAG1 and MAG2 may be optimized, in part, by adjusting the materials and thickness of the CL. The RL structure may also include a ferromagnetic lateral coupling layer (LCL) that is in contact with at least one of MAG1 and MAG2 for mediating intergranular exchange coupling in the ferromagnetic layer or layers with which it is in contact (MAG2 or MAG1). The ferromagnetic alloy in the LCL has significantly greater intergranular exchange coupling than the ferromagnetic alloy with which it is in contact (MAG2 or MAG1).
摘要:
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.
摘要翻译:垂直磁记录系统使用交换弹簧式垂直磁记录介质。 介质具有记录层(RL),其包括ML上方的下介质层(ML)和多层交换弹簧层(ESL)。 较高的各向异性场(high-H k k N)较低的ML和多层ESL在耦合层之间交换耦合。 多层ESL具有由耦合层隔开的至少两个ESL,其中每个ESL具有基本上小于ML的H k k N。 具有多层ESL的交换弹簧结构利用写入场幅度和写场梯度随着与写入极的距离的函数而变化的优点。 可以独立地改变每个ESL的厚度和厚度值,以优化介质的整体记录性能。
摘要:
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. Because the LCL grain boundaries overlay the boundaries of the generally segregated and decoupled grains of MAG1, and the LCL and MAG1 grains are strongly coupled perpendicularly, the LCL introduces an effective intergranular exchange coupling in the MAG1.
摘要:
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.
摘要:
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., a low switching field, as well as lower intrinsic media noise, over a medium with a conventional single-layer RL.
摘要:
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. Because the LCL grain boundaries overlay the boundaries of the generally segregated and decoupled grains of MAG1, and the LCL and MAG1 grains are strongly coupled perpendicularly, the LCL introduces an effective intergranular exchange coupling in the MAG1.
摘要:
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. Because the LCL grain boundaries overlay the boundaries of the generally segregated and decoupled grains of MAG1, and the LCL and MAG1 grains are strongly coupled perpendicularly, the LCL introduces an effective intergranular exchange coupling in the MAG1.
摘要:
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. Because the LCL grain boundaries overlay the boundaries of the generally segregated and decoupled grains of MAG2, and the LCL and MAG2 grains are strongly coupled perpendicularly, the LCL introduces an effective intergranular exchange coupling in the MAG2.