Abstract: A perpendicular magnetic recording medium is disclosed that is characterized by a lowered noise component and improved thermal stability. The method for making the recording medium includes the serial steps of forming a soft magnetic back-lining layer on a non-magnetic substrate, forming an intermediate layer on the soft magnetic back-lining layer, forming a magnetic recording layer on the intermediate layer, and forming a protective film and then a liquid lubricating layer on the magnetic recording layer. Thermal treatment is executed after the formation of the magnetic recording layer and before the formation of the protective film, or after the formation of the protective film and before the formation of the liquid lubricating layer. The thermal-processing steps are is executed in a vacuum higher than about 0.1 Pa and in a thermal environment within a range from about 200° C. to about 250° C. for a period of less than about 60 seconds.

Abstract: A perpendicular magnetic recording medium is disclosed that achieves improved recordability without deteriorating thermal stability by reducing the switching field. A perpendicular magnetic recording medium of the invention has a first magnetic recording layer and a second magnetic recording layer between with is interposed a coupling layer that ferromagnetically couples the two layers. The first and second magnetic recording layers satisfy an inequality Ku1T1>Ku2T2 in the case where Hk1 >Hk2 and an inequality Ku1T1<Ku2T2 in the case where Hk1<Hk2, where Hk1 and Hk2 are anisotropy magnetic fields, Ku1 and Ku2 are uniaxial anisotropy constants, and T1 and T2 are thicknesses of the first magnetic recording layer and the second recording layer, respectively. An exchange coupling energy between the magnetic recording layers is preferably at least 5×10?3 erg/cm2.

Abstract: A perpendicular magnetic recording medium is provided that achieves excellent magnetic performance by suppressing spike noises due to a soft magnetic backing layer, as well as good productivity. The perpendicular magnetic recording medium comprises at least a soft magnetic backing layer, an antiferromagnetic layer, an nonmagnetic underlayer, and a magnetic recording layer sequentially laminated on a nonmagnetic substrate, wherein the magnetic recording layer has a granular structure, the nonmagnetic underlayer is composed of ruthenium or a ruthenium alloy having an hcp structure having a thickness of at least 5 nm, the antiferromagnetic layer is composed of an alloy having an fcc structure and containing at least manganese, and the antiferromagnetic layer is laminated directly on the soft magnetic backing layer. Preferably, the antiferromagnetic layer is composed of an IrMn alloy, and the soft magnetic backing layer has an fcc structure and contains at least nickel and iron.

Abstract: A perpendicular magnetic recording medium includes a soft magnetic backing layer, an underlayer, a nonmagnetic intermediate layer, and a magnetic recording layer sequentially deposited on a nonmagnetic substrate. The underlayer can contain cobalt, nickel, and iron and have an fcc structure and exhibit soft magnetic property. The underlayer preferably contains nickel in a range of 30 to 88 at % and iron in a range of 0.1 to 22 at %. The underlayer can further contain Si, B, Nb, N, Ta, Al, Pd, Cr, or Mo. The nonmagnetic intermediate layer preferably contains at least one element selected from Ru, Re, Pd, Ir, Pt, and Rh. The magnetic recording layer preferably has a granular structure. A seed layer can be further provided between the soft magnetic backing layer and the underlayer.

Abstract: A perpendicular magnetic recording medium is disclosed in which each magnetic crystal grain in the magnetic recording layer has a multilayer structure and has a configuration like a truncated cone shape, in which the crystal grain of the final layer deposited in the film surface side at the final stage is smaller than the diameter of the crystal grain in the initial layer deposited on the substrate side at the initial stage. The invention improves S/N (signal output to noise ratio) by enhancing signal output and reducing noises. The medium is produced by a simple manufacturing method suitable for mass production, and provides a medium of high recording density by improving recording resolution.

Abstract: A perpendicular magnetic recording medium has a nonmagnetic substrate, a nonmagnetic underlayer, a magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on the substrate. The nonmagnetic layer is composed of a metal or alloy having a hcp crystal structure. The magnetic recording layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary phase mainly composed of an oxide surrounding the grains. A seed layer of a metal or alloy having a fcc crystal structure can be provided under the nonmagnetic underlayer, and a nonmagnetic alignment control layer can be provided under the seed layer. The recording medium can provide high output and low noise by improving the alignment of the magnetic recording layer, reducing the initial growth layer in the magnetic recording layer, and minimizing the grain size of the magnetic recording layer.

Abstract: A performance of a perpendicular magnetic recording medium, such as an increase in output or a decrease in noise, is improved by providing a good orientation of a magnetic recording layer in the perpendicular magnetic recording medium and by reducing an amount of an initial growth layer in the magnetic recording layer. The perpendicular magnetic recording medium includes an under layer, a magnetic recording layer, a protective film, and a liquid lubrication layer, which are sequentially provided on a non-magnetic substrate. The under layer contains non-magnetic NiFeCr or a permalloy-based soft magnetic material.

Abstract: A perpendicular magnetic recording medium is disclosed that is characterized by a lowered noise component and improved thermal stability. The method for making the recording medium includes the serial steps of forming a soft magnetic back-lining layer on a non-magnetic substrate, forming an intermediate layer on the soft magnetic back-lining layer, forming a magnetic recording layer on the intermediate layer, and forming a protective film and then a liquid lubricating layer on the magnetic recording layer. Thermal treatment is executed after the formation of the magnetic recording layer and before the formation of the protective film, or after the formation of the protective film and before the formation of the liquid lubricating layer. The thermal-processing steps are is executed in a vacuum higher than about 0.1 Pa and in a thermal environment within a range from about 200° C. to about 250° C. for a period of less than about 60 seconds.

Abstract: A perpendicular magnetic recording media and method of manufacturing therefore includes a nonmagnetic substrate, an underlayer deposited on the nonmagnetic substrate, and a magnetic recording layer formed on the underlayer, quickly heated, and quenched. A protective layer is deposited on the magnetic recording layer, and a liquid lubricant layer is deposited on the protective layer, to improve an uniaxial anisotropy Ku and a coercive force Hc of the magnetic recording layer.

Abstract: A perpendicular magnetic recording medium, which suppresses generation of spike noises, has a soft magnetic backing layer constructed of a laminated structure. The backing layer has at least one nonmagnetic metal layer at most 5 nm thick and at least two soft magnetic layers each at least 10 nm thick being alternately laminated, with the top layer and the bottom layer being the soft magnetic layers. The nonmagnetic metal layer is composed of a metal selected from Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au, or an alloy of these metals. The directions of magnetization in the two soft magnetic layers sandwiching the nonmagnetic metal layer are parallel to the plane of the soft magnetic layer and different from each other by 180 degrees, and the two soft magnetic layers are antiferromagnetically coupled. This structure prevents formation of magnetic domain walls when an external magnetic field is applied, thus suppressing spike noises.

Abstract: A perpendicular magnetic recording media and method of manufacturing therefore includes a nonmagnetic substrate, an underlayer deposited on the nonmagnetic substrate, and a magnetic recording layer formed on the underlayer, quickly heated, and quenched. A protective layer is deposited on the magnetic recording layer, and a liquid lubricant layer is deposited on the protective layer, to improve an uniaxial anisotropy Ku and a coercive force Hc of the magnetic recording layer.

Abstract: A perpendicular magnetic recording medium has a nonmagnetic substrate, a nonmagnetic underlayer, a magnetic layer, a protective film, and a liquid lubrication layer sequentially laminated on the substrate. The nonmagnetic layer is composed of a metal or alloy having a hcp crystal structure. The magnetic recording layer consists of ferromagnetic crystal grains and a nonmagnetic grain boundary phase mainly composed of an oxide surrounding the grains. A seed layer of a metal or alloy having a fcc crystal structure can be provided under the nonmagnetic underlayer, and a nonmagnetic alignment control layer can be provided under the seed layer. The recording medium can provide high output and low noise by improving the alignment of the magnetic recording layer, reducing the initial growth layer in the magnetic recording layer, and minimizing the grain size of the magnetic recording layer.

Abstract: A perpendicular magnetic recording media and method of manufacturing therefore includes a nonmagnetic substrate, an underlayer deposited on the nonmagnetic substrate, and a magnetic recording layer formed on the underlayer, quickly heated, and quenched. A protective layer is deposited on the magnetic recording layer, and a liquid lubricant layer is deposited on the protective layer, to improve an uniaxial anisotropy Ku and a coercive force Hc of the magnetic recording layer.

Abstract: A performance of a perpendicular magnetic recording medium, such as an increase in output or a decrease in noise, is improved by providing a good orientation of a magnetic recording layer in the perpendicular magnetic recording medium and by reducing an amount of an initial growth layer in the magnetic recording layer. The perpendicular magnetic recording medium includes an under layer, a magnetic recording layer, a protective film, and a liquid lubrication layer, which are sequentially provided on a non-magnetic substrate. The under layer contains non-magnetic NiFeCr or a permalloy-based soft magnetic material.