According to one embodiment, a magnetic head includes first and second magnetic poles, a stacked body, and first to third terminals. The stacked body is provided between the first and second magnetic poles. The stacked body includes a first magnetic layer, a second magnetic layer between the first magnetic layer and the second magnetic pole, a third magnetic layer between the second magnetic layer and the second magnetic pole, a fourth magnetic layer between the third magnetic layer and the second magnetic pole, a first nonmagnetic layer between the first magnetic pole and the first magnetic layer, a second nonmagnetic layer between the first and second magnetic layers, a third nonmagnetic layer between the second and third magnetic layers, a fourth nonmagnetic layer between the third and fourth magnetic layers and a fifth nonmagnetic layer between the fourth magnetic layer and the second magnetic pole.

According to one embodiment, a magnetic head includes first and second magnetic poles, a stacked body, and first to third terminals. The stacked body is provided between the first and second magnetic poles. The stacked body includes a first magnetic layer, a second magnetic layer between the first magnetic layer and the second magnetic pole, a third magnetic layer between the second magnetic layer and the second magnetic pole, a fourth magnetic layer between the third magnetic layer and the second magnetic pole, a first nonmagnetic layer between the first magnetic pole and the first magnetic layer, a second nonmagnetic layer between the first and second magnetic layers, a third nonmagnetic layer between the second and third magnetic layers, a fourth nonmagnetic layer between the third and fourth magnetic layers and a fifth nonmagnetic layer between the fourth magnetic layer and the second magnetic pole.

A magnetic recording device includes a main pole, a coil around the main pole, a trailing shield, and a spin torque oscillation device between the main pole and the trailing shield. The spin torque oscillation device includes one or more first layers, a spacer layer, and a field generation layer. The one or more first layers are over the main pole. The one or more first layers have a first heat conductance or include a low-heat-conductance material. The spacer layer is over the one or more first layers. The field generation layer is over the spacer layer. A heat sink is in contact with the trailing shield. The heat sink has a second heat conductance or includes a high-heat-conductance material. The second heat conductance of the heat sink is higher than the first heat conductance of the one or more first layers.

A magnetic recording device includes a main pole, a coil around the main pole, a trailing shield, and a spin torque oscillation device between the main pole and the trailing shield. The spin torque oscillation device includes one or more first layers, a spacer layer, and a field generation layer. The one or more first layers are over the main pole. The one or more first layers have a first heat conductance or include a low-heat-conductance material. The spacer layer is over the one or more first layers. The field generation layer is over the spacer layer. A heat sink is in contact with the trailing shield. The heat sink has a second heat conductance or includes a high-heat-conductance material. The second heat conductance of the heat sink is higher than the first heat conductance of the one or more first layers.

The present disclosure is generally related to a magnetic recording device comprising a magnetic recording head having a current flow in a cross-track direction around a main pole. The magnetic recording device comprises a main pole disposed between a trailing shield, a leading shield, and side shields. A trailing gap is disposed between the main pole and the trailing shield. A hot seed layer is disposed between the trailing gap and the trailing shield. A first insulation layer is disposed between the hot seed layer and the trailing shield, where the first insulation layer contacts the side shields. A second insulation layer is disposed between the main pole and leading shield, where the second insulation layer contacts the side shields. The first and second insulation layers direct the current through the side shields and across the main pole in a cross-track direction.

A magnetic tape device includes a magnetic tape; and a Tunneling Magnetoresistive (PAR) head as a reproducing head, in which the center line average surface roughness Ra measured regarding a surface of the magnetic layer of the magnetic tape is equal to or smaller than 2.0 nm, the logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and SFD in a longitudinal direction of the magnetic tape calculated by Expression 1: SFD=SFD.sub.25 C.SFD.sub.190 C. is equal to or smaller than 0.50, wherein, in Expression 1, the SFD.sub.25 C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25 C., and the SFD.sub.190 C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 190 C.

A magnetic tape device includes a magnetic tape; and a Tunneling Magnetoresistive (PAR) head as a reproducing head, in which the center line average surface roughness Ra measured regarding a surface of the magnetic layer of the magnetic tape is equal to or smaller than 2.0 nm, the logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and SFD in a longitudinal direction of the magnetic tape calculated by Expression 1: SFD=SFD.sub.25 C.SFD.sub.190 C. is equal to or smaller than 0.50, wherein, in Expression 1, the SFD.sub.25 C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25 C., and the SFD.sub.190 C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 190 C.

A microwave assisted magnetic recording (MAMR) writer has a recessed spin flipping element formed in the write gap between the MP tapered trailing side and a first trailing shield, a thickness to the write gap thickness, and a width to a maximum width of the MP tapered trailing side. The spin flipping element has a lower non-spin preserving layer, a middle flux guiding layer (FGL), and an upper spin preserving layer. The FGL has a magnetization that flips to a direction substantially anti-parallel to the write gap field when a current of sufficient magnitude is applied from the trailing shield towards the MP thereby increasing reluctance in the write gap and forcing additional flux out of the MP at the air bearing surface to enhance writability and tracks per inch capability on a recording medium while maintaining bits per inch capability compared with conventional MAMR writers.

A microwave assisted magnetic recording (MAMR) writer has a recessed spin flipping element formed in the write gap between the MP tapered trailing side and a first trailing shield, a thickness to the write gap thickness, and a width to a maximum width of the MP tapered trailing side. The spin flipping element has a lower non-spin preserving layer, a middle flux guiding layer (FGL), and an upper spin preserving layer. The FGL has a magnetization that flips to a direction substantially anti-parallel to the write gap field when a current of sufficient magnitude is applied from the trailing shield towards the MP thereby increasing reluctance in the write gap and forcing additional flux out of the MP at the air bearing surface to enhance writability and tracks per inch capability on a recording medium while maintaining bits per inch capability compared with conventional MAMR writers.

A ferroelectric recording medium includes an electrode layer, a ferroelectric recording layer, and a protection layer formed in this order on a substrate, wherein the ferroelectric recording layer includes a ferroelectric layer, the ferroelectric layer has an amorphous structure with short-range order, a distance of the short-range order is equal to or less than 2 nm, and a lattice constant of the amorphous structure and the lattice constant of the material constituting the substrate are lattice-matched within a range of ?10%.