Abstract: According to one embodiment, a magnetic recording device includes a magnetic head, and an electrical circuit. The magnetic head includes a magnetic pole, a first shield, and a stacked body provided between the magnetic pole and the first shield. The stacked body includes a first magnetic layer, a second magnetic layer, a first layer provided between the first and second magnetic layers, and a first nonmagnetic layer provided between the first magnetic layer and the first layer. A change rate of an electrical resistance of the stacked body with respect to a change of a current density flowing in the stacked body has a first value when the current density is in a first range, a second value when the current density is in a second range, and a third value when the current density is in a third range.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole, a first shield, a first magnetic layer, a second magnetic layer, a third magnetic layer, a first intermediate layer, a second intermediate layer, a third intermediate layer, and a fourth intermediate layer. The first magnetic layer is provided between the magnetic pole and the first shield. The second magnetic layer is provided between the first magnetic layer and the first shield. The third magnetic layer is provided between the second magnetic layer and the first shield. The first intermediate layer is provided between the magnetic pole and the first magnetic layer. The second intermediate layer is provided between the first magnetic layer and the second magnetic layer. The third intermediate layer is provided between the second magnetic layer and the third magnetic layer. The fourth intermediate layer is provided between the third magnetic layer and the first shield.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole, a first shield, a first magnetic layer provided between the magnetic pole and the first shield, a second magnetic layer provided between the first magnetic layer and the first shield, and an intermediate layer provided between the first magnetic layer and the second magnetic layer. The intermediate layer is nonmagnetic. A first distance between the magnetic pole and the first magnetic layer along a first direction is not less than 1% and not more than 10% of a second distance between the magnetic pole and the first shield along the first direction. The first direction is from the first magnetic layer toward the second magnetic layer.

Abstract: According to one embodiment, a magnetic recording device includes a magnetic head, a first electrical circuit, and a second electrical circuit. The magnetic head includes a magnetic pole, a first shield, a conductive member electrically connecting the magnetic pole and the first shield and being provided between the magnetic pole and the first shield, and a coil. The first electrical circuit is configured to supply a first current to the magnetic pole, the conductive member, and the first shield. The second electrical circuit is configured to supply a recording current to the coil. A recording magnetic field is generated from the magnetic pole. The recording magnetic field corresponds to the recording current. A rise time of the recording current is not less than 65% of a shortest bit length.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole, a first shield, a magnetic layer, and first and second conductive layers. The magnetic layer is provided between the magnetic pole and the first shield. The first conductive layer contacts the first shield and the magnetic layer, is provided between the first shield and the magnetic layer, and includes at least one element selected from Cu, Ag, and Au. The second conductive layer is provided between the magnetic pole and the magnetic layer. The second conductive layer includes first and second regions. The first region contacts the magnetic layer and includes at least one first element selected from Cu, Ag, Au, Al, Ti, Ru, Mg, and V. The second region is provided between the first region and the magnetic pole and includes at least one second element selected from Ta, Pt, W, Mo, Ir, Cr, Tb, Rh, and Pd.

Abstract: According to one embodiment, a method for evaluating a magnetic head is disclosed. The method can include measuring an electrical characteristic of a current path when an alternating-current magnetic field is applied to the magnetic head. The magnetic head includes the current path. The current path includes an oscillator. The method can include, based on the electrical characteristic, deriving a frequency value relating to an oscillation frequency of the oscillator.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole, a first shield, a magnetic layer, a first conductive layer, and a second conductive layer. The magnetic layer is provided between the magnetic pole and the first shield. The first conductive layer includes at least one of Cu, Ag, Au, Al and Cr, and is provided between the magnetic pole and the first shield. A direction from the first conductive layer toward the magnetic layer crosses a first direction from the magnetic pole toward the first shield. A second conductive layer includes at least one of Ta, Pt, W, Ru, Mo, Ir, Rh, and Pd and is provided at one of a first position or a second position. The first position is between the first conductive layer and the first shield. The second position is between the magnetic pole and the first conductive layer.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole, a first shield, a magnetic layer, first and second conductive layers. The magnetic layer is provided between the magnetic pole and the first shield. The first conductive layer contacts the first shield and the magnetic layer, is provided between the first shield and the magnetic layer, and includes at least one selected from Cu, Ag, and Au. The second conductive layer is provided between the magnetic pole and the magnetic layer. The second conductive layer includes first and second regions. The first region contacts the magnetic layer and includes at least one first element selected from Cu, Ag, Au, Al, Ti, Ru, Mg, and V. The second region is provided between the first region and the magnetic pole and includes at least one second element selected from Ta, Pt, W, Mo, Ir, Cr, Tb, Rh, and Pd.

Abstract: According to one embodiment, a magnetic recording device includes a magnetic head, a first electrical circuit, and a second electrical circuit. The magnetic head includes a magnetic pole, a first shield, a conductive member electrically connecting the magnetic pole and the first shield and being provided between the magnetic pole and the first shield, and a coil. The first electrical circuit is configured to supply a first current to the magnetic pole, the conductive member, and the first shield. The second electrical circuit is configured to supply a recording current to the coil. A recording magnetic field is generated from the magnetic pole. The recording magnetic field corresponds to the recording current. A rise time of the recording current is not less than 65% of a shortest bit length.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole, a first shield, a magnetic layer, a first conductive layer, and a second conductive layer. The magnetic layer is provided between the magnetic pole and the first shield. The first conductive layer includes at least one of Cu, Ag, Au, Al and Cr, and is provided between the magnetic pole and the first shield. A direction from the first conductive layer toward the magnetic layer crosses a first direction from the magnetic pole toward the first shield. A second conductive layer includes at least one of Ta, Pt, W, Ru, Mo, Ir, Rh, and Pd and is provided at one of a first position or a second position. The first position is between the first conductive layer and the first shield. The second position is between the magnetic pole and the first conductive layer.

Abstract: A magnetic recording apparatus includes a magnetic recording medium; a magnetic recording head including a first magnetic pole part, a second magnetic pole part, and a magnetic flux control part provided between the first magnetic pole part and the second magnetic pole part, wherein the magnetic flux control part includes a first layer provided between the first magnetic pole part and the second magnetic pole part, a second layer provided between the first magnetic pole part and the first layer, and a third layer provided between the second magnetic pole part and the first layer; an electrode for applying a current to the magnetic flux control part; and an electric circuit for energizing the current to the electrode, wherein an oscillation frequency of magnetization of the magnetic layer is greater than a ferromagnetic resonance frequency of the magnetic recording medium.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes an output driver, a magnetic head, and a magnetic recording medium. The output driver outputs a recording signal corresponding to input information. The magnetic head includes a coil. A recording current includes the recording signal flows in the coil. Information corresponding to the input information is recorded in the magnetic recording medium. The input information includes first, second, and third information combinations. The first information combination includes first to fourth information. The second information combination includes fifth to eighth information. The third information combination includes ninth to twelfth information. The recording signal changes to an eleventh recording current to correspond to the eleventh information. The recording signal changes to a third recording current to correspond to the third information.

Abstract: According to one embodiment, a magnetic recording and reproducing device includes an output driver, a magnetic head, and a magnetic recording medium. The output driver outputs a recording signal corresponding to input information. The magnetic head includes a coil. A recording current includes the recording signal flows in the coil. Information corresponding to the input information is recorded in the magnetic recording medium. The input information includes first, second, and third information combinations. The first information combination includes first to fourth information. The second information combination includes fifth to eighth information. The third information combination includes ninth to twelfth information. The recording signal changes to an eleventh recording current to correspond to the eleventh information. The recording signal changes to a third recording current to correspond to the third information.

Abstract: A magnetic recording apparatus includes a magnetic recording medium; a magnetic recording head including a first magnetic pole part, a second magnetic pole part, and a magnetic flux control part provided between the first magnetic pole part and the second magnetic pole part, wherein the magnetic flux control part includes a first layer provided between the first magnetic pole part and the second magnetic pole part, a second layer provided between the first magnetic pole part and the first layer, and a third layer provided between the second magnetic pole part and the first layer; an electrode for applying a current to the magnetic flux control part; and an electric circuit for energizing the current to the electrode, wherein an oscillation frequency of magnetization of the magnetic layer is greater than a ferromagnetic resonance frequency of the magnetic recording medium.

Abstract: In one embodiment, a magnetic sensor has first and second electrode, a magneto-resistive effect element, an insulating layer between the first electrode and the element, a current source portion and a detecting portion. The element has a length in a first direction along a film surface of the element which is larger than that in a second direction along the film surface and perpendicular to the first direction. The element includes first, non-magnetic and second magnetic layers. The magnetization direction of the first magnetic layer is along the first direction. The element is connected to the first and second electrodes. The current source portion is connected to the first and second electrodes. The detecting portion can detect a second harmonic component in an output signal of the element. The first electrode and the element overlap each other in a third direction perpendicular to the first and the second directions.

Abstract: According to one embodiment, a magnetic recording and reproducing device which has a magnetic recording medium, a magnetic head, and a recording current output unit. Magnetic data is recorded on the magnetic recording medium. The magnetic head records the magnetic data on the magnetic recording medium. The recording current output unit supplies a recording current to the magnetic head so as to magnetize the magnetic head. A waveform of the recording current has a first slope for a first period to record data of first information continuously and a second slope for a following second period to switch the data to data of second information and to record the data of the second information. The first slope and the second slope are different from each other.

Abstract: According to one embodiment, a magnetic recording and reproducing device which has a magnetic recording medium, a magnetic head, and a recording current output unit. Magnetic data is recorded on the magnetic recording medium. The magnetic head records the magnetic data on the magnetic recording medium. The recording current output unit supplies a recording current to the magnetic head so as to magnetize the magnetic head. A waveform of the recording current has a first slope for a first period to record data of first information continuously and a second slope for a following second period to switch the data to data of second information and to record the data of the second information. The first slope and the second slope are different from each other.

Abstract: A magnetic recording and reproducing device according to an embodiment includes a magnetic recording medium and a controller. The magnetic recording medium includes in sequence a substrate, a storage layer, an exchange layer, and a surface recording layer. The controller executes following steps (1) to (6): (1) magnetically recording first information on the surface recording layer; (2) transferring the first information recorded on the surface recording layer to the storage layer; (3) magnetically recording second information on the surface recording layer; (4) magnetically reproducing the second information from the surface recording layer; (5) transferring the first information recorded on the storage layer to the surface recording layer; and (6) magnetically reproducing the first information transferred to the surface recording layer.

Abstract: According to one embodiment, a magnetic head includes a magnetic pole, and a coil. The coil includes a first coil portion separated from the magnetic pole in a first direction. The magnetic pole includes a magnetic pole end portion, and first and second magnetic pole edge portions connected to the magnetic pole end portion. The first coil portion includes first and second coil edge portions, and a third coil edge portion overlapping the magnetic pole and being connected to the first and second coil edge portions. The first magnetic pole edge portion includes a first magnetic pole overlap portion overlapping the first coil edge portion. The second magnetic pole edge portion includes a second magnetic pole overlap portion overlapping the second coil edge portion. The magnetic pole end portion has a magnetic pole end portion center in a second direction connecting the first and second magnetic pole overlap portions.

Abstract: According to one embodiment, a magnetic head includes first and second shields, a magnetic pole, and a trailing shield. The magnetic pole is provided between the first and second shields. The trailing shield is separated from the magnetic pole. The first shield includes first magnetic layers and first nonmagnetic layers arranged alternately along a first stacking direction. The first nonmagnetic layers include at least one selected from the group consisting of Ru, Cu, and Cr. Thicknesses of the first nonmagnetic layers each is not less than 0.3 nanometers and not more than 2.2 nanometers. The second shield includes second magnetic layers and second nonmagnetic layers arranged alternately along a second stacking direction. The second nonmagnetic layers include at least one selected from the group consisting of Ru, Cu, and Cr. Thicknesses of the second nonmagnetic layers each is not less than 0.3 nanometers and not more than 2.2 nanometers.