US 12,068,004 B2Granted

Magnetic recording device

AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation

InventorsYuji Nakagawa, Naoyuki Narita, Masayuki Takagishi, Tomoyuki Maeda

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Abstract

According to one embodiment, a magnetic recording device includes a magnetic head and a controller. The magnetic head includes first and second magnetic poles, a magnetic element provided between the first and second magnetic poles, and first and second terminals. The controller is configured to perform a recording operation. In the recording operation, the controller is configured to supply a recording current to the coil while applying an element voltage not less than a first voltage and not more than a second voltage between the first terminal and the second terminal. A differential resistance of the magnetic element when a positive applied voltage applied between the first terminal and the second terminal is changed while the recording current is supplied to the coil becomes a first peak when the applied voltage is the first voltage.

Claims20

Dependent claims

A magnetic recording device, comprising:

a magnetic head including
a first magnetic pole,
a second magnetic pole,
a magnetic element provided between the first magnetic pole and the second magnetic pole,
a first terminal electrically connected to the first magnetic pole,
a second terminal electrically connected to the second magnetic pole, and
a coil;
and
a controller electrically connected to the first terminal, the second terminal, and the coil,
an end of the magnetic element being electrically connected to the first magnetic pole,
another end of the magnetic element being electrically connected to the second magnetic pole,
the controller being configured to perform a recording operation,
in the recording operation, the controller being configured to supply a recording current to the coil while applying an element voltage not less than a first voltage and not more than a second voltage between the first terminal and the second terminal,
when the element voltage, the first voltage and the second voltage being applied, a second potential of the second magnetic pole being lower than a first potential of the first magnetic pole,
a differential resistance of the magnetic element when a positive applied voltage applied between the first terminal and the second terminal being changed while the recording current being supplied to the coil becoming a first peak when the applied voltage being the first voltage,
when the positive applied voltage being applied, the second potential being lower than the first potential,
when a first applied voltage being applied between the first terminal and the second terminal while the recording current being supplied to the coil, a first signal being generated between the first terminal and the second terminal,
the first signal having a first intensity when the first applied voltage being a first value of positive,
the first signal having a second intensity when the first applied voltage being a second value of negative,
a ratio of an absolute value of a difference between the first intensity and the second intensity to a normalized change rate being not less than 1 at the second voltage,
an absolute value of the second value being same as the first value,
when the first applied voltage being positive, the second potential being lower than the first potential,
when the first applied voltage being negative, the second potential being higher than the first potential, and
the normalized change rate being a product of the first voltage and an absolute value of the change rate of the second intensity with respect to the first applied voltage when the first applied voltage being negative.

21 more elements

A magnetic recording device, comprising:

a magnetic head including
a first magnetic pole,
a second magnetic pole,
a magnetic element provided between the first magnetic pole and the second magnetic pole,
a first terminal electrically connected to the first magnetic pole,
a second terminal electrically connected to the second magnetic pole, and
a coil;
and
a controller electrically connected to the first terminal, the second terminal, and the coil,
an end of the magnetic element being electrically connected to the first magnetic pole,
another end of the magnetic element being electrically connected to the second magnetic pole,
the controller being configured to perform a recording operation,
in the recording operation, the controller being configured to supply a recording current to the coil while applying an element voltage not less than a first voltage and not more than a second voltage between the first terminal and the second terminal,
when the element voltage, the first voltage and the second voltage being applied, a second potential of the second magnetic pole being lower than a first potential of the first magnetic pole,
a differential resistance of the magnetic element when a positive applied voltage applied between the first terminal and the second terminal being changed while the recording current being supplied to the coil becoming a first peak when the applied voltage being the first voltage,
the differential resistance becoming a second peak when the positive applied voltage being a third voltage,
the third voltage being higher than the first voltage and lower than the second voltage,
when the positive applied voltage being applied, the second potential being lower than the first potential,
when a first applied voltage being applied between the first terminal and the second terminal while the recording current being supplied to the coil, a first signal being generated between the first terminal and the second terminal,
the first signal having a first intensity when the first applied voltage being a first value of positive,
the first signal having a second intensity when the first applied voltage being a second value of negative,
a ratio of an absolute value of a difference between the first intensity and the second intensity to a normalized change rate being not less than 5 at the second voltage,
when the first applied voltage being positive, the second potential being lower than the first potential,
when the first applied voltage being negative, the second potential being higher than the first potential,
an absolute value of the second value being same as the first value,
the normalized change rate being a product of the first voltage and an absolute value of the change rate of the second intensity with respect to the first applied voltage when the first applied voltage being negative.

23 more elements

A magnetic recording device, comprising:

a magnetic head including
a first magnetic pole,
a second magnetic pole,
a magnetic element provided between the first magnetic pole and the second magnetic pole,
a first terminal electrically connected to the first magnetic pole,
a second terminal electrically connected to the second magnetic pole, and
a coil;
and
a controller electrically connected to the first terminal, the second terminal, and the coil,
an end of the magnetic element being electrically connected to the first magnetic pole,
another end of the magnetic element being electrically connected to the second magnetic pole,
the controller being configured to perform a recording operation,
in the recording operation, the controller being configured to supply a recording current to the coil while applying an element voltage not less than a first voltage and not more than a second voltage between the first terminal and the second terminal,
when the element voltage, the first voltage and the second voltage being applied, a second potential of the second magnetic pole being lower than a first potential of the first magnetic pole,
a first signal being configured to be generated between the first terminal and the second terminal when a first applied voltage being applied between the first terminal and the second terminal while the recording current being supplied to the coil,
the second potential being lower than the first potential when the first applied voltage being applied,
an intensity of a component of a first frequency of the first signal changing according to a change in the first applied voltage,
the first frequency being not less than 10 Hz and not more than 3 GHZ,
the first applied voltage including a first voltage range not less than the first voltage and not more than the second voltage, a second voltage range exceeding the second voltage, and a third voltage range less than the first voltage,
a change rate of the intensity with respect to the change of the first applied voltage being a first change rate in the first voltage range, a second change rate in the second voltage range, and a third change rate in the third voltage range, and
the second change rate being higher than the first change rate, and the third change rate of change being lower than the first change rate.

18 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/358,850Filed 25 Jul 2023
Priority: JP 2022-1973389 Dec 2022
Published: US 2024/0194223 A113 Jun 2024
Granted: 20 Aug 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G11B 20/10009
Digital recording or reproducing: improvement or modification of read or write signals
G11B 5/02
Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor: recording,…
G11B 5/09
Recording, reproducing, or erasing methods; Read, write or erase circuits therefor: digital recording
G11B 5/1278
Structure or manufacture of heads, e.g. inductive: specially adapted for magnetisations perpendicular to the surface of the record carrier