Abstract: A magnetic recording medium includes a substrate and a magnetic recording layer formed on the substrate. The magnetic recording layer includes a recording region on which a magnetic material is formed as a bit pattern, and a spacing layer which fills a peripheral area of the recording region with a non-magnetic material with relatively higher thermal conductivity than that of the magnetic material.

Abstract: Embodiments of the present invention help to suppress the effects of thermal fluctuation in a thermally assisted magnetic field recording, and improve recording density. According to one embodiment, a recording area of a magnetic disk is heated and the full width at half maximum of an optical power distribution of a near field light generator is controlled to be 100 nm or less. Thereby, the cooling time of the magnetic disk is made 2 nm or less and the effects of thermal fluctuation are suppressed. Moreover, although an incomplete area of the magnetization reversal at the rear end of the magnetic domain is created with rapid cooling, by creating an overshoot at the rising end of the magnetic field waveform of the magnetic recording head, the incomplete area of the magnetization reversal can be overwritten, which is created at the rear end of the magnetic domain previously recorded by the overshoot magnetic field.

Abstract: One purpose of the invention according to one embodiment is to provide a magnetic recording apparatus of high recording density in which magnetization transition curvature amount of a recording pattern is small. In one embodiment, the center of a heating area is arranged at a track edge side of a recording pattern as compared with the width-direction center position of a main magnetic pole of a recording head, and a recording magnetic field is applied while a medium is locally heated at the time of signal recording. A switching magnetic field of the medium is locally reduced by heating, so that a line where the switching magnetic field of the medium is equal to the recording magnetic field from the head approaches the heating center position, and a desired recording pattern in which the transition curvature amount is reduced can be realized. Other systems and methods are also presented.

Abstract: The aim of the present invention is to apply an intense magnetic field to a portion where an optical near-field is generated by a thermal assisted magnetic recording head with a scatterer having conductivity as an optical near-field generating element. To this end, a scatterer for generating an optical near-field is formed in a bottom portion of a slider, and a magnetic field is applied thereto using a coil. In order to increase the intensity of the magnetic field, a magnetic pole made of a soft magnetic material is formed over the scatterer.

Abstract: A thermally assisted magnetic recording medium includes a substrate and at least two, i.e., first and second magnetic recording layers. These layers are hard magnetic layers and contain magnetic grains and a non-magnetic substance magnetically segregating the magnetic grains at grain boundaries. The first magnetic recording layer has a magnetic anisotropy energy Ku1, a grain volume v1, and energy for maintaining its recording magnetization Ku1v1; the second magnetic recording layer has a magnetic anisotropy energy Ku2, a grain volume v2, and energy for maintaining its recording magnetization Ku2v2; and the ratio Ku1v1/kBT of Ku1v1 to a thermal fluctuation energy kBT, where kB represents a Boltzmann constant and T represents an absolute temperature, and the ratio Ku2v2/kBT of Ku2v2 to kBT satisfy the following conditions: Ku1v1/kBT is larger than Ku2v2/kBT at room temperature, but is smaller than Ku2v2/kBT at temperatures around the Curie temperature of the first magnetic recording layer.

Abstract: A thermally assisted magnetic recording system is provided to achieve excellent thermal resistance and low noise. In one embodiment, a magnetic recording medium is used, in which the magnetic intergrain exchange coupling is large to let the magnetization be thermally stable by coupling the magnetic grains constituting the recording layer at room temperature (the temperature maintaining the magnetization) and reduced by heating during recording to let the recording magnetization transition slope become steep. Parameter A normalizing the slope around the coercivity of the MH-loop of the medium is 1.5?A<6.0 at room temperature, and it becomes approximately 1.0 with heating.

Abstract: The optimum head-field intensity for saturation recording is assumed to be 560×103 A/m or more. Under a condition where the recording track width of an information recording medium is equal to or less than 60 nm, the optimum head-field intensity Y satisfies the following inequalities (1) and (2): Y?(X2?119×X+4135)×1000??(1) Y?(X2?119×X+const)×1000??(2) where X denotes the nondimensional value of the recording track width divided by 10?9 m, and Y denotes a magnetic field (expressed in units of A/m) which a magnetic pole for head-field application applies to the center of the information recording medium in the direction of the thickness thereof. Note that const=?0.8×v2+33.7×v+4250 if the relative velocity v between the head and the medium at the position of the head is less than 20 m/sec, or const=4600 if the velocity v is equal to or more than 20 m/sec.

Abstract: A thermally assisted magnetic recording medium includes a substrate and at least two, i.e., first and second magnetic recording layers. These layers are hard magnetic layers and contain magnetic grains and a non-magnetic substance magnetically segregating the magnetic grains at grain boundaries. The first magnetic recording layer has a magnetic anisotropy energy Ku1, a grain volume v1, and energy for maintaining its recording magnetization Ku1v1; the second magnetic recording layer has a magnetic anisotropy energy Ku2, a grain volume v2, and energy for maintaining its recording magnetization Ku2v2; and the ratio Ku1v1/kBT of Ku1v1 to a thermal fluctuation energy kBT, where kB represents a Boltzmann constant and T represents an absolute temperature, and the ratio Ku2v2/kBT of Ku2v2 to kBT satisfy the following conditions: Ku1v1/kBT is larger than Ku2v2/kBT at room temperature, but is smaller than Ku2v2/kBT at temperatures around the Curie temperature of the first magnetic recording layer.

Abstract: One purpose of the invention according to one embodiment is to provide a magnetic recording apparatus of high recording density in which magnetization transition curvature amount of a recording pattern is small. In one embodiment, the center of a heating area is arranged at a track edge side of a recording pattern as compared with the width-direction center position of a main magnetic pole of a recording head, and a recording magnetic field is applied while a medium is locally heated at the time of signal recording. A switching magnetic field of the medium is locally reduced by heating, so that a line where the switching magnetic field of the medium is equal to the recording magnetic field from the head approaches the heating center position, and a desired recording pattern in which the transition curvature amount is reduced can be realized. Other systems and methods are also presented.

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 thermally assisted magnetic recording system is provided to achieve excellent thermal resistance and low noise. In one embodiment, a magnetic recording medium is used, in which the magnetic intergrain exchange coupling is large to let the magnetization be thermally stable by coupling the magnetic grains constituting the recording layer at room temperature (the temperature maintaining the magnetization) and reduced by heating during recording to let the recording magnetization transition slope become steep. Parameter A normalizing the slope around the coercivity of the MH-loop of the medium is 1.5?A<6.0 at room temperature, and it becomes approximately 1.0 with heating.

Abstract: A thermally assisted magnetic recording system is provided to achieve excellent thermal resistance and low noise. In one embodiment, a magnetic recording medium is used, in which the magnetic intergrain exchange coupling is large to let the magnetization be thermally stable by coupling the magnetic grains constituting the recording layer at room temperature (the temperature maintaining the magnetization) and reduced by heating during recording to let the recording magnetization transition slope become steep. Parameter A normalizing the slope around the coercivity of the MH-loop of the medium is 1.5?A<6.0 at room temperature, and it becomes approximately 1.0 with heating.

Abstract: Embodiments of the present invention help to suppress the effects of thermal fluctuation in a thermally assisted magnetic field recording, and improve recording density. According to one embodiment, a recording area of a magnetic disk is heated and the full width at half maximum of an optical power distribution of a near field light generator is controlled to be 100 nm or less. Thereby, the cooling time of the magnetic disk is made 2 nm or less and the effects of thermal fluctuation are suppressed. Moreover, although an incomplete area of the magnetization reversal at the rear end of the magnetic domain is created with rapid cooling, by creating an overshoot at the rising end of the magnetic field waveform of the magnetic recording head, the incomplete area of the magnetization reversal can be overwritten, which is created at the rear end of the magnetic domain previously recorded by the overshoot magnetic field.

Abstract: The optimum head-field intensity for saturation recording is assumed to be 560×103 A/m or more. Under a condition where the recording track width of an information recording medium is equal to or less than 60 nm, the optimum head-field intensity Y satisfies the following inequalities (1) and (2): Y?(X2?119×X+4135)×1000 ??(1) Y?(X2?119×X+const)×1000 ??(2) where X denotes the nondimensional value of the recording track width divided by 10?9 m, and Y denotes a magnetic field (expressed in units of A/m) which a magnetic pole for head-field application applies to the center of the information recording medium in the direction of the thickness thereof. Note that const=?0.8×v2+33.7×v+4250 if the relative velocity v between the head and the medium at the position of the head is less than 20 m/sec, or const=4600 if the velocity v is equal to or more than 20 m/sec.

Abstract: There are provided a magnetic head and a magnetic disk apparatus wherein an upper magnetic pole is so shaped that, at a position where skew angle is maximum, the maximum of its projected length in the radial direction of a magnetic disk is not more than the track pitch of the magnetic disk, whereby acceleration of thermal relaxation of information recorded on adjacent tracks is obviated even in an area where the skew angle is large.

Abstract: The aim of the present invention is to apply an intense magnetic field to a portion where an optical near-field is generated by a thermal assisted magnetic recording head with a scatterer having conductivity as an optical near-field generating element. To this end, a scatterer for generating an optical near-field is formed in a bottom portion of a slider, and a magnetic field is applied thereto using a coil. In order to increase the intensity of the magnetic field, a magnetic pole made of a soft magnetic material is formed over the scatterer.

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: There are provided a magnetic head and a magnetic disk apparatus wherein an upper magnetic pole is so shaped that, at a position where skew angle is maximum, the maximum of its projected length in the radial direction of a magnetic disk is not more than the track pitch of the magnetic disk, whereby acceleration of thermal relaxation of information recorded on adjacent tracks is obviated even in an area where the skew angle is large.

Abstract: A thermally assisted magnetic recording system is provided to achieve excellent thermal resistance and low noise. In one embodiment, a magnetic recording medium is used, in which the magnetic intergrain exchange coupling is large to let the magnetization be thermally stable by coupling the magnetic grains constituting the recording layer at room temperature (the temperature maintaining the magnetization) and reduced by heating during recording to let the recording magnetization transition slope become steep. Parameter A normalizing the slope around the coercivity of the MH-loop of the medium is 1.5?A<6.0 at room temperature, and it becomes approximately 1.0 with heating.

Abstract: There are provided a magnetic head and a magnetic disk apparatus wherein an upper magnetic pole is so shaped that, at a position where skew angle is maximum, the maximum of its projected length in the radial direction of a magnetic disk is not more than the track pitch of the magnetic disk, whereby acceleration of thermal relaxation of information recorded on adjacent tracks is obviated even in an area where the skew angle is large.