Headway Technologies, Incorporated

Kabushiki Kaisha Toshiba

Tdk Corporation

Joe Smyth

Moris Musa Dovek

Kenichi Takano

Yuchen Zhou

Xuhui Jin

Lijie Guan

Erhard Theodor Schreck

Tobias Maletzky

Yoshitaka Sasaki

Min Li

Kunliang Zhang

Cherng-Chyi Han

Dayu Zhou

Wenyu Chen

Liejie Guan

Po-Kang Wang

Kowang Liu

Yiming Wang

Xiaohua Lou

Masayuki Takagishi

Zhigang Bai

Suping Song

Yan Wu

Akihiko Takeo

Tomomi Funayama

Glen A Garfunkel

Masahiro Takashita

PoKang Wang

Yiu Liu

Morris Dovek

A method of forming a TAMR (Thermal Assisted Magnetic Recording) write head that uses the energy of optical-laser excited plasmons to locally heat a magnetic recording medium and reduce its coercivity and magnetic anisotropy. The magnetic field of the write head is enhanced by the formation of a leading shield that is formed in a concave geometrical shape and partially surrounds the waveguide portion of the head within the concavity, which allows the distal end of the waveguide to extend to the ABS plane of the write head. This arrangement reduces the gap between the shield and the magnetic pole and does not interfere with the ability of the waveguide to efficiently transfer its optical energy to the plasmon generator and, ultimately, to the surface of the magnetic recording medium.

Method of forming a TAMR writer with a concave leading shield for enhanced field magnitude

A TAMR (Thermal Assisted Magnetic Recording) write head uses the energy of optical-laser excited surface plasmons in a plasmon generator to locally heat a magnetic recording medium and reduce its coercivity and magnetic anisotropy. The optical radiation is transmitted to the plasmon generator by means of a waveguide, whose optical axis (centerline) is tilted relative to either or both the backside surface normal and ABS surface normal in order to eliminate back reflections of the optical radiation that can adversely affect the properties and performance of the laser. Variations of the disclosure include tilting the plasmon generator, the waveguide and the laser diode.

Tilted structures to reduce reflection in laser-assisted TAMR

A method for measuring the frequency in a spin torque oscillator having at least a magnetic oscillation layer (MOL), junction layer, and magnetic reference layer (MRL) is disclosed. In a first embodiment, a small in-plane magnetic field is applied to the STO after a DC current is applied to excite the MOL into an oscillation state. The MRL has a perpendicular magnetization that is tilted slightly to give an in-plane magnetization component to serve as a reference layer for measuring the oscillation frequency of the MOL in-plane magnetization component. An AC voltage change is produced in the DC current as a result of variable STO resistance and directly correlates to MOL oscillation frequency. Alternatively, a field having both perpendicular and in-plane components may be applied externally or by forming the STO between two magnetic poles thereby producing an in-plane magnetization reference component in the MRL.

Perpendicular spin torque oscillator FMR frequency measurement method

A structure and a process for a perpendicular write pole that provides increased magnetic flux at the ABS is disclosed. This is accomplished by increasing the amount of write flux that originates above the write gap, without changing the pole taper at the ABS. Three embodiment of the invention are discussed.

Graded bevel tapered write pole design for field enhancement

A TAMR (Thermally Assisted Magnetic Recording) write head is formed with a narrow pole tip, a trailing edge magnetic shield and, optionally, a plasmon shield. The narrow pole tipped write head uses the energy of laser generated edge plasmons, formed in a plasmon generating layer, to locally heat a PMR magnetic recording medium slightly below its Curie temperature, Tc. When combined with the effects of the narrow tip, this local heating to a temperature below Tc is sufficient to create good transitions and narrow track widths in the magnetic medium. The write head is capable of writing effectively on state-of-the-art PMR recording media having Hk of 20 kOe or more.

Heat assisted narrow pole design with trailing shield

A method of manufacturing a PMR writer is disclosed that minimizes pole erasure during non-writing and maximize write field during writing by including an AFM-FM phase change material spacer that is in an AFM state during non-writing and switches to a FM state by heating during writing. The main pole layer including the write pole may be formed as a laminated structure by a sputter deposition process wherein a plurality of 'n' ferromagnetic layers and 'n&#x2212;1' AFM-FM phase change material layers are laid down in an alternating manner. The AFM-FM phase change material is preferably a FeRh or FeRhX alloy (X=Pt, Pd, or Ir) having a Rh content &#x3e;35 atomic %, and may also be used as a flux gate to prevent yoke flux from leaking into the write pole tip.

Method of manufacturing a perpendicular magnetic recording head laminated with AFM-FM phase change material

A method is described to improve performance of a magneto-resistive (MR) sensor under conditions of high areal density. The free layer is partially etched away, the removed material being replaced by a magnetic flux guide structure that reduces the free layer's demagnetization field. This in turn reduces the stripe height of the sensor so that the resolution and the read-back signal are enhanced without increasing noise and instability.

Method to improve performance of a magneto-resistive (MR) sensor

A design is disclosed for a microwave assisted magnetic recording device wherein direct current and rf current are simultaneously injected from a bias tee into a spin transfer oscillator (STO) between a main pole and write shield to improve the assist process. The STO oscillation layer (OL) has a large angle magnetization oscillation frequency that is locked to a magnetic medium bit resonance frequency f0 when the rf current has a frequency f=f0 and a threshold current density is applied. Alternatively, the OL magnetization oscillation frequency may be adjusted closer to f0 to improve the assist process. A third advantage is lowering the threshold current density when both direct current and rf current are injected into the STO during a write process. The main pole is grounded when direct current and rf current are injected into a write shield.

Magnetic recording assisted by spin torque oscillator with a radio frequency current bias

A TAMR (Thermal Assisted Magnetic Recording) write head uses the near field energy of optical-laser excited plasmon eigenmodes in a plasmon resonator to locally heat a magnetic recording medium and reduce its coercivity and magnetic anisotropy. The plasmon resonator is formed as a conducting disk-shaped structure with an extending peg that serves to further confine the near fields within a small region of the recording medium. The resonator eigenmodes are excited, through direct or evanescent coupling, by an interference pattern formed by the overlap of optical waves within a dual-channel waveguide, the interference pattern being the result of the waves in one branch being phase-shifted relative to the waves in the other branch.

Plasmon resonator with dual waveguide excitation for TAMR

A method to tune an oscillation layer frequency in a spin torque oscillator (STO) during a microwave assisted magnetic recording (MAMR) process is described. The STO oscillation layer (OL) has a large angle magnetization oscillation frequency that is locked to a magnetic medium bit resonance frequency f0 when the rf current has a frequency f=f0 and a threshold current density is applied. Alternatively, the OL magnetization oscillation frequency may be adjusted closer to f0 to improve the assist process. A third advantage is lowering the threshold current density when both direct current and rf current are injected into the STO during a write process. The main pole is grounded when direct current and rf current are injected into a write shield.

A device for implementing thermally assisted magnetic recording, using a TE mode laser diode, and method for using it, are described. This device is shaped internally so as to provide three-dimensional self-focusing of plasmon radiation, thereby improving the coupling efficiency between the optical wave-guide and the plasmon generator as a result of ensuring a large overlap between these two modes.

3-D self-focusing gap plasmon generator for TAMR

A TAMR (Thermal Assisted Magnetic Recording) write head uses the energy of optical-laser excited plasmons to locally heat a magnetic recording medium and reduce its coercivity and magnetic anisotropy. The magnetic field of the write head is enhanced by the formation of a leading shield that is formed in a concave geometrical shape and partially surrounds the waveguide portion of the head within the concavity, which allows the distal end of the waveguide to extend to the ABS plane of the write head. This arrangement reduces the gap between the shield and the magnetic pole and does not interfere with the ability of the waveguide to efficiently transfer its optical energy to the plasmon generator and, ultimately, to the surface of the magnetic recording medium.

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Aptos, CA, United States of America

Joe Smyth