公开(公告)号：US09666216B1

公开(公告)日：2017-05-30

申请号：US15181490

申请日：2016-06-14

Applicant: TDK Corporation

Inventor： Tatsuhiro Kobayashi ,  Sadaharu Yoneda ,  Tsutomu Aoyama

IPC: G11B27/36 ,  G11B5/39 ,  G11B5/09 ,  G11B5/17 ,  G11B5/00

CPC classification number: G11B5/3909 ,  G11B5/02 ,  G11B5/09 ,  G11B5/17 ,  G11B5/235 ,  G11B5/3123 ,  G11B5/3146 ,  G11B2005/0024

Abstract: A magnetic recording device includes a magnetic recording medium, a microwave assisted magnetic head having a main magnetic pole for generating a recording magnetic field, and a spin torque oscillator provided near the main magnetic pole for generating a microwave magnetic field, a recording current supply part for supplying a recording current to recording coils according to recording current waveform data, a drive current supply part for supplying a drive current to the spin torque oscillator, and a drive current control part for controlling supply of the drive current by the drive current supply part based on the data. Taking into consideration as an indicator whether a polarity reversal interval included in the data exceeds a threshold time, the drive current control part controls the drive current supply part so as not to substantially lower the quality of signals recorded on the magnetic recording medium.

公开(公告)号：US09318132B2

公开(公告)日：2016-04-19

申请号：US14658904

申请日：2015-03-16

Applicant: TDK CORPORATION

Inventor： Tetsuhito Shinohara ,  Tsutomu Aoyama ,  Yoshikazu Soeno

IPC: G11B5/127 ,  G11B5/31 ,  G11B5/00

CPC classification number: G11B5/314 ,  G11B5/3116 ,  G11B5/3146 ,  G11B2005/0024

Abstract: A magnetic head includes a main magnetic pole used to apply a recording signal magnetic field to a magnetic recording medium and also includes a microwave line through which a microwave alternating current is transferred. The microwave line is connected to the main magnetic pole. The entire end surface of the main magnetic pole is positioned closer to air bearing surface than a connection portion at which the microwave line and main magnetic pole are mutually connected. Therefore, microwave assisted magnetic recording is possible without deteriorating the recording signal magnetic field.

Abstract translation: 磁头包括用于将记录信号磁场施加到磁记录介质的主磁极，并且还包括传输微波交流电的微波线。 微波线路连接到主磁极。 主磁极的整个端面比微波线路和主磁极相互连接的连接部分靠近空气轴承表面。 因此，微波辅助磁记录是可能的，而不会使记录信号磁场恶化。

公开(公告)号：US09299366B2

公开(公告)日：2016-03-29

申请号：US14566028

申请日：2014-12-10

Applicant: TDK CORPORATION

Inventor： Tsutomu Aoyama ,  Akimasa Kaizu ,  Tetsuhito Shinohara ,  Yoshikazu Soeno

IPC: G11B5/66 ,  G11B5/127 ,  G11B5/02 ,  G11B5/31 ,  G11B5/00

CPC classification number: G11B5/02 ,  G11B5/3116 ,  G11B5/3146 ,  G11B5/66 ,  G11B2005/0024

Abstract: A magnetic recording and reproducing apparatus includes a magnetic recording medium including a recording layer in which at least two magnetic layers are layered on a non-magnetic substrate; and a magnetic head including a main magnetic pole for applying a recording magnetic field in a direction substantially perpendicular to a recording face of the magnetic recording medium and a microwave generating element that generates a microwave magnetic field. The relationship between a thickness Ts of a magnetic layer having a lowest magnetic anisotropy energy among the at least two magnetic layers composing the recording layer of the magnetic recording medium, and a thickness Tt of the recording layer is Ts/Tt≦0.2. The microwave generating element applies the microwave magnetic field having a width broader than the width of the recording magnetic field generated by the main magnetic pole of the magnetic head to the magnetic recording medium.

Abstract translation: 一种磁记录和再现装置包括：磁记录介质，其包括在非磁性基板上层叠有至少两个磁性层的记录层; 以及包括用于在基本上垂直于磁记录介质的记录面的方向上施加记录磁场的主磁极的磁头和产生微波磁场的微波产生元件。 构成磁记录介质的记录层的至少两个磁性层中的具有最低磁各向异性能的磁性层的厚度Ts与记录层的厚度Tt之间的关系为Ts / Tt＆nlE; 0.2。 微波产生元件将具有比由磁头的主磁极产生的记录磁场的宽度宽的宽度的微波磁场施加到磁记录介质。

公开(公告)号：US08680855B2

公开(公告)日：2014-03-25

申请号：US13726767

申请日：2012-12-26

Applicant: TDK Corporation

Inventor： Isamu Sato ,  Hiroshi Ikeda ,  Mikio Matsuzaki ,  Tetsuya Roppongi ,  Noboru Yamanaka ,  Tsutomu Aoyama

IPC: G01R33/02

CPC classification number: G11B5/455 ,  G01R33/098 ,  G01R33/1284

Abstract: A measuring circuit system in a magnetic field measuring apparatus of the invention has an amplifier and a band-pass filter connected in sequence on an output terminal side of the TMR element, the band-pass filter is a narrow-range band-pass filter such that a peak pass frequency of the filter that is a center is a basic frequency selected from a range of 10 to 40 GHz and a band width centered around the basic frequency is a narrow range of ±0.5 to ±4 GHz; and with the measuring circuit system, an S/N ratio (SNR) of 3 dB or greater is obtained, the SNR being defined by a ratio of an amplitude S of a high-frequency generated signal induced by the TMR element to a total noise N that is a sum of a head noise generated by the TMR element and a circuit noise generated by the amplifier. With such a configuration, an in-plane high-frequency magnetic field generated by a microwave-assisted magnetic head is reliably and precisely measured.

Abstract translation: 本发明的磁场测量装置中的测量电路系统具有在TMR元件的输出端侧依次连接的放大器和带通滤波器，带通滤波器是窄范围带通滤波器， 作为中心的滤波器的峰值通过频率是从10〜40GHz的范围选择的基本频率，以基本频率为中心的带宽为±0.5〜±4GHz的窄范围; 并且利用测量电路系统，获得3dB或更大的S / N比（SNR），SNR由TMR元件引起的高频产生信号的振幅S与总噪声的比率定义 N是由TMR元件产生的头噪声和由放大器产生的电路噪声之和。 通过这样的结构，可以可靠且精确地测量由微波辅助磁头产生的面内高频磁场。