Abstract: According to one embodiment, a magnetic head includes first and second magnetic poles, and a stacked body provided between the first and second magnetic poles. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic pole, a third magnetic layer provided between the second magnetic layer and the second magnetic pole, a first nonmagnetic layer provided between the first and second magnetic layers, a second nonmagnetic layer provided between the second and third magnetic layers, and a third nonmagnetic layer provided between the first magnetic pole and the first magnetic layer. A first magnetic pole length of the first magnetic pole is less than a second magnetic pole length of the second magnetic pole. A first magnetic layer length of the first magnetic layer is greater than a second magnetic layer length of the second magnetic layer.

Abstract: According to one embodiment, a magnetic head includes a recording portion. The recording portion includes a magnetic pole, a shield, and a stacked body provided between the magnetic pole and the shield. The stacked body includes a first magnetic layer, a first layer provided between the first magnetic layer and the magnetic pole, and a first intermediate layer provided between the first magnetic layer and the shield. The first layer contacts the magnetic pole and includes at least one selected from the group consisting of IrMn, PtMn, FeMn, PdMn, NiMn, RhMn, MnCr, and PtCr. The first intermediate layer includes at least one selected from a first group consisting of Cu, Ag, Au, Al, Cr, and Ru.

Abstract: According to one embodiment, a magnetic head includes a shield, a magnetic pole, a first magnetic layer provided between the shield and the magnetic pole, a second magnetic layer provided between the first magnetic layer and the magnetic pole, a third magnetic layer provided between the second magnetic layer and the magnetic pole, a first nonmagnetic layer provided between the shield and the first magnetic layer, a second nonmagnetic layer provided between the first magnetic layer and the second magnetic layer, a third nonmagnetic layer provided between the second magnetic layer and the third magnetic layer, and a fourth nonmagnetic layer provided between the third magnetic layer and the magnetic pole. The first and third nonmagnetic layers include one of Cu, Ag, Au, Al, and Ti. The second and fourth nonmagnetic layers include one of Ta, Pt, Ir, W, Mo, Cr, Tb, Rh, Pd, and Ru.

Abstract: According to one embodiment, a magnetic head includes a first magnetic pole, a second magnetic pole, and a stacked body provided between the first and second magnetic poles. The stacked body includes a first magnetic member, a second magnetic member provided between the first magnetic member and the second magnetic pole, a first layer provided between the first and second magnetic members, and a second layer provided between the second magnetic member and the second magnetic pole. The first magnetic member includes first magnetic regions and a first nonmagnetic region. The first nonmagnetic region is between the one of the first magnetic regions and the other one of the first magnetic regions. The second magnetic member includes second magnetic regions and a second nonmagnetic region. The second nonmagnetic region is between the one of the second magnetic regions and the other one of the second magnetic regions.

Abstract: According to one embodiment, a magnetic head includes a shield, a magnetic pole, a first magnetic layer provided between the shield and the magnetic pole, a second magnetic layer provided between the first magnetic layer and the magnetic pole, a third magnetic layer provided between the second magnetic layer and the magnetic pole, a first nonmagnetic layer provided between the shield and the first magnetic layer, a second nonmagnetic layer provided between the first magnetic layer and the second magnetic layer, a third nonmagnetic layer provided between the second magnetic layer and the third magnetic layer, and a fourth nonmagnetic layer provided between the third magnetic layer and the magnetic pole. The first and third nonmagnetic layers include one of Cu, Ag, Au, Al, and Ti. The second and fourth nonmagnetic layers include one of Ta, Pt, Ir, W, Mo, Cr, Tb, Rh, Pd, and Ru.

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 recording portion. The recording portion includes a magnetic pole, a shield, and a stacked body provided between the magnetic pole and the shield. The stacked body includes a first magnetic layer, a first layer provided between the first magnetic layer and the magnetic pole, and a first intermediate layer provided between the first magnetic layer and the shield. The first layer contacts the magnetic pole and includes at least one selected from the group consisting of IrMn, PtMn, FeMn, PdMn, NiMn, RhMn, MnCr, and PtCr. The first intermediate layer includes at least one selected from a first group consisting of Cu, Ag, Au, Al, Cr, and Ru.

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 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, and an electrical circuit. The magnetic head includes a first magnetic pole, a second magnetic pole, and a stacked body provided between the first and the second magnetic poles. The stacked body includes a first nonmagnetic layer, a first magnetic layer provided between the first nonmagnetic layer and the second magnetic pole, a first layer provided between the first magnetic layer and the second magnetic pole, a second nonmagnetic layer provided between the first layer and the second magnetic pole, a second magnetic layer provided between the second nonmagnetic layer and the second magnetic pole, and a third nonmagnetic layer provided between the second magnetic layer and the second magnetic pole. The electrical circuit supplies, to the stacked body, a first current having a first orientation from the second magnetic pole toward the first magnetic pole.

Abstract: According to one embodiment, a magnetic head includes first and second shields, a magnetic pole, a first magnetic layer, and a first nonmagnetic member. The first shield includes first, second, and third partial regions. A first direction is from the second toward third partial region. The first partial region is between the second and third partial regions. A second direction from the first toward second shield crosses the first direction. The magnetic pole between the second and third partial regions in the first direction is provided between the first partial region and the second shield in the second direction. The first magnetic layer is provided between the magnetic pole and the second shield. The first nonmagnetic member includes first and second portions. The first portion is between the magnetic pole and the first magnetic layer. The second portion is between the second partial region and the second shield.

Abstract: According to the embodiment, a magnetic recording device includes a magnetic head, a magnetic recording medium, 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 first, and second magnetic layers, first, second, and third nonmagnetic layers. An electrical resistance of the stacked body is a first resistance when a current flowing in the stacked body is a first current. The electrical resistance is a second resistance when the current flowing in the stacked body is a second current. The electrical resistance oscillates when the current flowing in the stacked body is a third current. The electrical circuit is configured to supply the second current to the stacked body in a recording operation of using the magnetic head to record information in the magnetic recording medium.

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 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 shield, a magnetic pole, a first magnetic layer provided between the shield and the magnetic pole, a second magnetic layer provided between the first magnetic layer and the magnetic pole, a third magnetic layer provided between the second magnetic layer and the magnetic pole, a first nonmagnetic layer provided between the shield and the first magnetic layer, a second nonmagnetic layer provided between the first magnetic layer and the second magnetic layer, a third nonmagnetic layer provided between the second magnetic layer and the third magnetic layer, and a fourth nonmagnetic layer provided between the third magnetic layer and the magnetic pole. The first and third nonmagnetic layers include one of Cu, Ag, Au, Al, and Ti. The second and fourth nonmagnetic layers include one of Ta, Pt, Ir, W, Mo, Cr, Tb, Rh, Pd, and Ru.

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.