Abstract: A perpendicular magnetic recording medium according to an embodiment includes a substrate and perpendicular magnetic recording layer. The perpendicular magnetic recording layer includes a recording portion and non-recording portion. The recording portion has patterns regularly arranged in the longitudinal direction, and includes magnetic layers containing Fe or Co and Pt as main components, and at least one additive component selected from Ti, Si, Al, and W. The non-recording portion includes oxide layers formed by oxidizing the side surfaces of the magnetic layers, and nonmagnetic layers formed between the oxide layers.

Abstract: According to one embodiment, a magnetic recording head includes a magnetic pole, a stacked body, and a first non-magnetic layer. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the magnetic pole, and a non-magnetic intermediate layer provided between the first magnetic layer and the second magnetic layer. The first non-magnetic layer is provided between the second magnetic layer and the magnetic pole, and contacts the magnetic pole and the second magnetic layer. The first magnetic layer has a first thickness and a first saturation magnetic flux density. The second magnetic layer has a second thickness and a second saturation magnetic flux density. A second product of the second thickness and the second saturation magnetic flux density is larger than a first product of the first thickness and the first saturation magnetic flux density.

Abstract: According to one embodiment, a method of manufacturing a magnetic recording head includes forming a microwave oscillator to cover a main pole and a side shield and also to cross at least a part of a side gap between the main pole and the side shield, and lapping the main pole, the side shield and the microwave oscillator in a height direction while monitoring an electric resistance between the main pole and the side shield.

Abstract: According to one embodiment, a magnetic recording head includes a magnetic pole, a stacked body, and a first nonmagnetic layer. The stacked body includes first magnetic layer, a second magnetic layer provided between the first magnetic layer and the magnetic pole, and an intermediate layer provided between the first magnetic layer and the second magnetic layer and being nonmagnetic. The first nonmagnetic layer is provided between the second magnetic layer and the magnetic pole. A product of a thickness and a saturation magnetic flux density of the second magnetic layer is larger than a product of a thickness and a saturation magnetic flux density of the first magnetic layer. The length of the first magnetic layer is shorter than a length of the second magnetic layer. A current flows from the second magnetic layer toward the first magnetic layer.

Abstract: According to one embodiment, a magnetic recording head includes a magnetic pole, a stacked body, and a first nonmagnetic layer. The stacked body includes first magnetic layer, a second magnetic layer provided between the first magnetic layer and the magnetic pole, and an intermediate layer provided between the first magnetic layer and the second magnetic layer and being nonmagnetic. The first nonmagnetic layer is provided between the second magnetic layer and the magnetic pole. A product of a thickness and a saturation magnetic flux density of the second magnetic layer is larger than a product of a thickness and a saturation magnetic flux density of the first magnetic layer. The length of the first magnetic layer is shorter than a length of the second magnetic layer. A current flows from the second magnetic layer toward the first magnetic layer.

Abstract: According to one embodiment, there is provided a spin torque oscillator including an oscillation layer formed of a magnetic material, a spin injection layer formed of a magnetic material and configured to inject a spin into the oscillation layer, and a current confinement layer including an insulating portion formed of an oxide or a nitride and a conductive portion formed of a nonmagnetic metal and penetrating the insulating portion in a direction of stacking. The conductive portion of the current confinement layer is positioned near a central portion of a plane of a device region including the oscillation layer and the spin injection layer.

Abstract: According to one embodiment, a magnetic recording head includes a magnetic pole, a stacked body, and a first non-magnetic layer. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the magnetic pole, and a non-magnetic intermediate layer provided between the first magnetic layer and the second magnetic layer. The first non-magnetic layer is provided between the second magnetic layer and the magnetic pole, and contacts the magnetic pole and the second magnetic layer. The first magnetic layer has a first thickness and a first saturation magnetic flux density. The second magnetic layer has a second thickness and a second saturation magnetic flux density. A second product of the second thickness and the second saturation magnetic flux density is larger than a first product of the first thickness and the first saturation magnetic flux density.

Abstract: According to one embodiment, a method of manufacturing a magnetic recording head includes forming a microwave oscillator to cover a main pole and a side shield and also to cross at least a part of a side gap between the main pole and the side shield, and lapping the main pole, the side shield and the microwave oscillator in a height direction while monitoring an electric resistance between the main pole and the side shield.

Abstract: According to one embodiment, a recording head includes a recoding magnetic pole which applies a recording magnetic field, a write shield which faces the recording magnetic pole across a recording gap, and a spin-torque oscillator provided in the recording gap between the recording magnetic pole and the write shield. The spin-torque oscillator is physically and/or magnetically destroyed and has resistance greater than or equal to a predetermined value.

Abstract: A perpendicular magnetic recording medium according to an embodiment includes a substrate and perpendicular magnetic recording layer. The perpendicular magnetic recording layer includes a recording portion and non-recording portion. The recording portion has patterns regularly arranged in the longitudinal direction, and includes magnetic layers containing Fe or Co and Pt as main components, and at least one additive component selected from Ti, Si, Al, and W. The non-recording portion includes oxide layers formed by oxidizing the side surfaces of the magnetic layers, and nonmagnetic layers formed between the oxide layers.

Abstract: According to one embodiment, there is provided a method for forming a pattern including forming an island-like metal underlayer comprised of a first metal, a phase-separated release layer including a first metal, a second metal, and a metal oxide, a mask layer, and a resist layer on a processed layer in this order, forming a concave-convex pattern on the resist layer, transferring the pattern to the mask layer, the phase-separated release layer, and the processed layer in this order, dissolving the phase-separated release layer using a peeling liquid for dissolving the first metal and the second metal, and removing the mask layer from the processed layer to expose the concave-convex pattern.

Abstract: According to one embodiment, a microwave-assisted magnetic head includes a main magnetic pole configured to apply a recording magnetic field to a magnetic recording medium, an auxiliary magnetic pole configured to constitute a magnetic circuit together with the main magnetic pole, and a domain propagation element including a domain propagation path having two ends and a magnetic anisotropy perpendicular to a domain propagation direction, and a domain input portion configured to write a magnetic domain in the domain propagation path, and a current supply mechanism connected to the domain propagation path, and at least part of the domain propagation path passes between the main magnetic pole and the auxiliary magnetic pole.

Abstract: According to one embodiment, a pattern formation method includes steps of forming a layer to be processed on a substrate, forming a metal microparticle layer by coating the layer to be processed with a metal microparticle coating solution containing metal microparticles and a solvent, reducing a protective group amount around the metal microparticles by first etching, forming a protective layer by exposing the substrate to a gas containing C and F and adsorbing the gas around the metal microparticles to obtain a projection pattern, and transferring the projection pattern to the layer to be processed by second etching.

Abstract: According to one embodiment, a magnetic recording medium including a substrate and a magnetic recording layer formed on the substrate and including a plurality of projections is obtained. The array of the plurality of projections includes a plurality of domains in which the projections are regularly arranged, and a boundary region between the domains, in which the projections are irregularly arranged. The boundary region is formed along a perpendicular bisector of a line connecting the barycenters of adjacent projections.

Abstract: According to one embodiment, a magnetic recording medium including a substrate and a magnetic recording layer formed on the substrate and including a plurality of projections is obtained. The array of the plurality of projections includes a plurality of domains in which the projections are regularly arranged, and a boundary region between the domains, in which the projections are irregularly arranged. The boundary region is formed along a perpendicular bisector of a line connecting the barycenters of adjacent projections.

Abstract: A method for measuring the frequency in a spin torque oscillator having at least a magnetic oscillation layer (MOL), junction layer, and magnetic reference layer (MRL) is disclosed. In a first embodiment, a small in-plane magnetic field is applied to the STO after a DC current is applied to excite the MOL into an oscillation state. The MRL has a perpendicular magnetization that is tilted slightly to give an in-plane magnetization component to serve as a reference layer for measuring the oscillation frequency of the MOL in-plane magnetization component. An AC voltage change is produced in the DC current as a result of variable STO resistance and directly correlates to MOL oscillation frequency. Alternatively, a field having both perpendicular and in-plane components may be applied externally or by forming the STO between two magnetic poles thereby producing an in-plane magnetization reference component in the MRL.

Abstract: A magnetic head includes a plurality of reproducing elements so that the magnetic head can acquire reproduction signals from a plurality of tracks at the same time. The magnetic head includes a first reproducing element, a first magnetic film formed on a first side wall of the first reproducing element with a first side wall insulating film interposed therebetween, a second magnetic film formed on a second side wall of the first reproducing element with a second side wall insulating film interposed therebetween, a second reproducing element electrically isolated from the first reproducing element and formed on the first magnetic film, a third magnetic film formed on the first magnetic film, and a fourth magnetic film formed on the first reproducing element and electrically isolated from the second reproducing element.

Abstract: A magnetic recording head includes a main magnetic pole that applies a recording magnetic field to a recording layer of a recording medium, a write shield that faces the main magnetic pole with a write gap therebetween, a recording coil that generates a magnetic field in the main magnetic pole, a high-frequency oscillator that includes a field generation layer and a spin injection layer, and is disposed within the write gap between the main magnetic pole and the write shield, a wiring electrically connected to the high-frequency oscillator, a modulation electrode that applies a modulation voltage to the field generation layer, and a modulation insulating layer that is interposed between the field generation layer and the modulation electrode.

Abstract: According to at least one embodiment, a metal peelable layer and a mask layer are formed on a magnetic recording layer, then, a projections pattern is formed on the mask layer, the projections pattern is transferred to the metal peelable layer and the magnetic recording layer in this order, and then the metal peelable layer is dissolved and removed by a solvent. The metal peelable layer is constituted of any of aluminum and an aluminum compound. An alkali solution is used as the solvent.

Abstract: According to one embodiment, a magnetic head includes a main pole configured to apply a recording magnetic field to a recording layer included in a recording medium, a trailing shield opposing the main pole in a down-track direction, with a write gap interposed therebetween, a pair of side shields opposing the main pole on opposite sides of the main pole in a cross-track direction, with respective gaps interposed therebetween, a recording coil configured to cause the main pole to generate a magnetic field, a first high-frequency oscillator interposed between the main pole and one of the side shields, and a second high-frequency oscillator interposed between the main pole and the other side shield.