According to one embodiment, among a plurality of magnetic heads, the larger the magnetic pole width of the magnetic pole of the magnetic head in the width direction of a recording track formed in a recording layer or the larger an area width of the magnetic head capable of reading the magnetic characteristics of an area of the recording layer on which magnetic recording has been carried out by means of the magnetic head, the farther is the magnetic head arranged outwardly from the vicinity of the center in the parallel arrangement direction of the magnetic disks.

According to one embodiment, among a plurality of magnetic heads, the larger the magnetic pole width of the magnetic pole of the magnetic head in the width direction of a recording track formed in a recording layer or the larger an area width of the magnetic head capable of reading the magnetic characteristics of an area of the recording layer on which magnetic recording has been carried out by means of the magnetic head, the farther is the magnetic head arranged outwardly from the vicinity of the center in the parallel arrangement direction of the magnetic disks.

According to one embodiment, among a plurality of magnetic heads, the larger the magnetic pole width of the magnetic pole of the magnetic head in the width direction of a recording track formed in a recording layer or the larger an area width of the magnetic head capable of reading the magnetic characteristics of an area of the recording layer on which magnetic recording has been carried out by means of the magnetic head, the farther is the magnetic head arranged outwardly from the vicinity of the center in the parallel arrangement direction of the magnetic disks.

In one embodiment, a write head includes a spin polarization layer (SPL) over a seed layer. A spacer layer is over the SPL. A trailing shield is over the spacer layer. The spacer layer forms a first interface between the spacer layer and the trailing shield and forms a second interface between the spacer layer and the SPL. The first interface has an area larger than an area of the second interface. In another embodiment, a write head includes a SPL over a spacer layer. A capping layer is over the SPL. A trailing shield is over the capping layer. The spacer layer forms a first interface between the spacer layer and the main pole and forms a second interface between the spacer layer and the SPL. The first interface has an area larger than an area of the second interface.

Disclosed herein are magnetic recording devices and methods of using them. A magnetic recording device comprises a main pole extending to an air-bearing surface (ABS), a trailing shield extending to the ABS, a write-field-enhancing structure disposed between and coupled to the main pole and the trailing shield at the ABS, a write coil configured to magnetize the main pole, a write current control circuit coupled to the write coil and configured to apply a write current to the write coil, wherein the write current comprises a write pulse, and a bias current control circuit coupled to the write-field-enhancing structure and configured to apply a bias current to the write-field-enhancing structure, wherein the bias current comprises a driving pulse offset in time from the write pulse by a delay, wherein the delay substantially coincides with an expected magnetization switch-time lag of a free layer of the write-field-enhancing structure.

A spin transfer torque (STT) device has a free ferromagnetic layer that includes a Heusler alloy layer and a template layer beneath and in contact with the Heusler alloy layer. The template layer may be a ferromagnetic alloy comprising one or more of Co, Ni and Fe and the element X, where X is selected from one or more of Ta, B, Hf, Zr, W, Nb and Mo. A CoFe nanolayer may be formed below and in contact with the template layer. The STT device may be a spin-torque oscillator (STO), like a STO incorporated into the write head of a magnetic recording disk drive. The STT device may also be a STT in-plane or perpendicular magnetic tunnel junction (MTJ) cell for magnetic random access memory (MRAM). The template layer reduces the critical current density of the STT device.

Disclosed herein are magnetic recording devices and methods of using them. A magnetic recording device comprises a main pole extending to an air-bearing surface (ABS), a trailing shield extending to the ABS, a write-field-enhancing structure disposed between and coupled to the main pole and the trailing shield at the ABS, a write coil configured to magnetize the main pole, a write current control circuit coupled to the write coil and configured to apply a write current to the write coil, wherein the write current comprises a write pulse, and a bias current control circuit coupled to the write-field-enhancing structure and configured to apply a bias current to the write-field-enhancing structure, wherein the bias current comprises a driving pulse offset in time from the write pulse by a delay, wherein the delay substantially coincides with an expected magnetization switch-time lag of a free layer of the write-field-enhancing structure.

According to one embodiment, among a plurality of magnetic heads, the larger the magnetic pole width of the magnetic pole of the magnetic head in the width direction of a recording track formed in a recording layer or the larger an area width of the magnetic head capable of reading the magnetic characteristics of an area of the recording layer on which magnetic recording has been carried out by means of the magnetic head, the farther is the magnetic head arranged outwardly from the vicinity of the center in the parallel arrangement direction of the magnetic disks.

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.

According to one embodiment, among a plurality of magnetic heads, the larger the magnetic pole width of the magnetic pole of the magnetic head in the width direction of a recording track formed in a recording layer or the larger an area width of the magnetic head capable of reading the magnetic characteristics of an area of the recording layer on which magnetic recording has been carried out by means of the magnetic head, the farther is the magnetic head arranged outwardly from the vicinity of the center in the parallel arrangement direction of the magnetic disks.