Magnetic head with plural read elements having pinned layers magnetic disk device comprising the same and reading method using magnetic head

Patent metadata

Field	Value
Publication number	US-2016171993-A1
Application number	US-201514639081-A
Country	US
Kind code	A1
Filing date	Mar 4, 2015
Priority date	Dec 10, 2014
Publication date	Jun 16, 2016
Grant date	—

Abstract

According to one embodiment, a magnetic head includes read elements each including a first magnetic layer having a pinned magnetization direction, and a second magnetic layer provided to oppose the first magnetic layer via an insulating layer therebetween and having a free magnetization direction. At least two of the read elements are arranged such that both of the first magnetic layer and the second magnetic layer of each of these elements cross an arbitrary line and the first magnetic layers of these elements are different in magnetization direction with respect each other.

First claim

1 . A magnetic head comprising:
a plurality of read elements each comprising a first magnetic layer having a pinned magnetization direction, a second magnetic layer opposing the first magnetic layer via an insulating layer therebetween and having a free magnetization direction, and an independent electrode in contact with the first and second magnetic layers to output a reading signal from each read element; wherein at least two of the plurality of read elements are arranged such that both of the first magnetic layer and the second magnetic layer of each of the at least two read elements cross an arbitrary line and the first magnetic layers of the at least two read elements are different in magnetization direction with respect each other.

2 . The magnetic head of claim 1 , wherein
the at least two read elements are arranged such that the magnetization directions thereof are in parallel and opposite to each other.

3 . The magnetic head of claim 1 , wherein
the plurality of read elements are arranged such that centers of at least two of the plurality of read elements are aligned on the arbitrary line and the first magnetic layers of the at least two read elements are different in magnetization direction with respect each other.

4 . The magnetic head of claim 1 , wherein
the plurality of read elements comprise a first read element and a third read element arranged such that centers thereof are located on a first axis, and a second read element and a fourth read element arranged such that centers thereof are located on a second axis extending in parallel with the first axis and away by a predetermined distance from the first axis, and the first, second, third and fourth read elements are aligned in a direction of the first axis at predetermined intervals.

5 . The magnetic head of claim 4 , wherein
the first, second and fourth read elements comprise pinned layers magnetized in a same direction, and the third read element comprises a pinned layer magnetized in a direction opposite to that of the pinned layer of the first read element.

6 . A magnetic disk device comprising:
a disk shaped recording medium; and the magnetic head of claim 1 , configured to read data of the recording medium.

7 . The magnetic disk device of claim 6 , further comprising: an equalization circuit configured to average reading signals of two series read by the at least two read element of the magnetic head based on respective weighting coefficients and to synthesize the signals.

8 . The magnetic disk device of claim 7 , further comprising: a controller configured to set the weighting coefficients according to a reading zone of the recording medium and a read element employed.

9 . The magnetic disk device of claim 6 , further comprising: a controller configured to select, according to a skew angle of the magnetic head with respect to a data track of the recording medium, two read elements located on a central axis of the data track from the plurality of read elements.

10 . The magnetic disk device of claim 6 , wherein the at least two read elements are arranged such that the magnetization directions thereof are in parallel and opposite to each other.

11 . The magnetic disk device of claim 6 , wherein the plurality of read elements are arranged such that centers of at least two of the plurality of read elements are aligned on the arbitrary line and the first magnetic layers of the at least two read elements are different in magnetization direction with respect each other.

12 . The magnetic disk device of claim 6 , wherein the plurality of read elements comprise a first read element and a third read element arranged such that centers thereof are located on a first axis, and a second read element and a fourth read element arranged such that centers thereof are located on a second axis extending in parallel with the first axis and away by a predetermined distance from the first axis, and the first, second, third and fourth read elements are aligned in a direction of the first axis at predetermined intervals.

13 . The magnetic disk device of claim 12 , wherein the first, second and fourth read elements comprise pinned layers magnetized in a same direction, and the third read element comprises a pinned layer magnetized in a direction opposite to that of the pinned layer of the first read element.

14 . A reading method of reading recording data recorded on a recording medium, using a magnetic head comprising a plurality of read elements each comprising a first magnetic layer having a pinned magnetization direction, a second magnetic layer provided to oppose the first magnetic layer via an insulating layer there between and having a free magnetization direction, and an independent electrode in contact with the first and second magnetic layers to output a reading signal from each read element, wherein at least two of the plurality of read elements are arranged such that both of the first magnetic layer and the second magnetic layer of each of the at least two read elements cross an arbitrary line and the first magnetic layers of the at least two read elements are different in magnetization direction with respect each other, the method comprising:
selecting, according to a skew angle of the magnetic head with respect to a data track of the recording medium, two read elements located on a central axis of the data track from the plurality of read elements; reading recording data on the data track by the selected two read elements; and averaging and synthesizing reading signals of two series read by the two read elements based on respective weighting coefficients.

15 . The method of claim 14 , further comprising: setting the weighting coefficients according to a reading zone of the recording medium and a read element employed.

16 . The magnetic head of claim 1 , wherein each of the plurality of read elements comprises an independent hard bias layer opposed to the first magnetic layer.

Assignees

• Toshiba Kk

Inventors

• Okubo Tomokazu

Classifications

• G11B20/10046

  filtering or equalising, e.g. setting the tap weights of an FIR filter · CPC title

• G11B5/31 Primary

  using thin films {(G11B5/1274, G11B5/1278, G11B5/1874, G11B5/1875, G11B5/33, G11B5/49 take precedence; magnetic thin film structures H01F10/00)} · CPC title

• G11B5/3179 Primary

  the films being mainly disposed in parallel planes · CPC title