Hgst Netherlands, B.v.

Hitachi, Ltd.

Hsgt Netherlands B.v.

Masato Matsubara

Masato Shiimoto

Keiichi Nagasaka

Masukazu Igarashi

Yo Sato

Masashige Sato

Kenji Sugiura

Hiroyuki Katada

Masaru Furukawa

Jianhua Li

Masato Shimoto

Yuta Udou

The present disclosure generally relates to a high-frequency oscillator for use in a recording device having a microwave-assisted magnetic recording head. The microwave-assisted magnetic recording head achieves a large assist effect by using an extended spin torque oscillator disposed between a main magnetic pole and a pole opposite the main magnetic pole. The spin torque oscillator obtains a strong high-frequency magnetic field and comprises a first non-magnetic spin scatterer, a reference layer, a first non-magnetic spin transfer layer, a first magnetic field generating layer, a second non-magnetic spin transfer layer, a second magnetic field generating layer, and a second non-magnetic spin scatterer. The spin torque oscillator has a drive current flowing though in the direction from the first magnetic field generating layer to the reference layer.

Extended spin torque oscillator

Embodiments disclosed herein generally relate to a MAMR head. The MAMR head includes an STO and a current switching system electrically coupled to the STO. The current switching system can be used to optimize the STO frequency by changing the STO bias polarity, i.e., by changing the direction of the current flowing to the STO. As a result, the difference between the STO frequency and the magnetic media frequency is minimized, which improves recording capability of the MAMR head.

Symmetrical STO for oscillation with both polarity bias

In one embodiment, a magnetic head includes a main pole configured to write data to a magnetic medium, a trailing shield positioned on a trailing side of the main pole, and a STO between the main pole and the trailing shield, wherein the STO includes a laminated structure having a FGL, a spun polarization layer (SPL), and a non-magnetic spacer positioned between the FGL and the SPL, wherein the FGL includes a laminated structure having one or more layers of a CoFe alloy and a Heusler alloy alternately laminated in this order from an end of the FGL closest to the non-magnetic spacer. In another embodiment, a method is presented for forming such a magnetic head utilizing a FGL that includes a laminated structure baying layers of a CoFe alloy and a Heusler alloy alternately laminated in this order from an end of the FGL closest to the non-magnetic spacer.

Magnetic head having a spin torque oscillator (STO) with a hybrid heusler field generation layer (FGL)

Embodiments of the present invention generally relate to a microwave assisted magnetic recording (MAMR) head. The MAMR head includes a main pole, a trailing shield, and a spin torque oscillator (STO) disposed between the main pole and the trailing shield. The STO is recessed from an air bearing surface.

MAMR head with recessed STO

In one embodiment, a microwave-assisted magnetic recording (MAMR) head includes a main pole configured to write data to a magnetic medium using a write magnetic field, a write coil, wherein the write magnetic field is produced by the main pole upon a recording current, I, being provided to the write coil, and a spin torque oscillator (STO) positioned near the main pole, the STO being configured to provide a high-frequency assistance magnetic field to the magnetic medium upon a STO drive current, I, being provided to the STO, wherein the STO drive current, I, is ramped-up prior to the recording current, I, being provided to the write coil in order to begin a write operation for writing data to the magnetic medium. A method of operation for the MAMR head and an apparatus including the MAMR head are also described according to additional embodiments.

Microwave-assisted magnetic recording (MAMR) head employing advanced current control to establish a magnetic resonance state

A microwave assisted magnetic recording write head having a spin torque oscillator capable of producing high strength high frequency magnetic oscillations with reduced applied current. The spin torque oscillator uses a magnetic field generation layer with a high moment material including such as Fe and Co that is formed on an interlayer having a face centered cubic (fcc) crystal structure, that functions as an under-layer. The high moment magnetic field generation layer has also reduced magnetic damping.

Spin-torque oscillator for microwave assisted magnetic recording

In a conventional type magnetic head that performs microwave assisted recording, since a difference in a demagnetizing field between an end and the center of a field generation layer (FGL) grows larger when saturation magnetization of the FGL grows larger, the FGL that generates a microwave is not oscillated in a state of a single domain. Then, a spin-torque oscillator according to the present invention used for a magnetic head for microwave assisted recording is provided with at least one fixed layer, one non-magnetic intermediate layer and one alternating-current magnetic field generation layer respectively and is provided with a structure where saturation magnetization at ends of a film except an end in a direction from an air bearing surface to a surface opposite to it is made smaller than saturation magnetization in the center of the film of the alternating-current magnetic field generation layer.

A spin torque oscillator for microwave assisted recording includes a perpendicular free layer having a magnetic anisotropy axis in a direction perpendicular to a film surface, and an in-plane free layer composed of a magnetic film effectively having a magnetization easy plane on a film surface. When electric currents flows from the in-plane free layer side to the perpendicular free layer side, both free layers exchange spin information and thereby rotate their respective magnetizations almost antiparallel to each other and along a boundary surface with high-speed. Preferably, the perpendicular free layer is thinner than the in-plane free layer. It is also preferable that a magnetic anisotropy field of the perpendicular free layer attributable to materials should balance, in reverse directions, with an effective demagnetizing field in the perpendicular direction. Furthermore, the perpendicular free layer is preferably placed on the main pole side.

Magnetic recording apparatus with magnetic recording head capable of recording information on a magnetic recording medium

In a magnetic recording device adopting a microwave assisted recording method, a microwave frequency on a positive polarity side and a microwave frequency on a negative polarity side are adjusted to be optimal. The magnetic recording device of the invention supplies to a magnetic head a write current of which a current waveform on the positive polarity side and a current waveform on the negative polarity side are asymmetric.

Magnetic recording device

In one embodiment, a magnetic data storage system includes a main pole power supply adapted for supplying an excitation current to a main pole coil, a microwave-assisted magnetic recording (MAMR) device including a spin-torque oscillator (STO) element, the STO element having a field generation layer (FGL) and a polarization layer, a timing-control circuit adapted for determining a duration of a main pole magnetic moment inversion process and signaling a start of the main pole magnetic moment inversion process, and a current-regulating circuit comprising an STO power supply adapted for supplying current to the STO element, wherein the STO power supply prevents degradation of a single rotating magnetic domain structure in the FGL into a closure magnetic domain structure in the FGL. Other systems and methods for preventing degradation of the single rotating magnetic domain structure in the FGL into a closure magnetic domain structure are described for more embodiments.

Spin-torque oscillator (STO) for microwave-assisted magnetic recording (MAMR) and methods of use thereof

The present invention provides a spin torque oscillator that can realize stable oscillation and has high reliability. A laminated structure including a first magnetic layerhaving a bcc crystal structure and having in-plane magnetic anisotropy and a second magnetic layerhaving perpendicular magnetic anisotropy laminated on the first magnetic layerand including a multilayer film of Co and Ni is used.

Growing community of inventors

Yokohama, Japan

Masato Matsubara