Magnetic head and magnetic recording/reproducing device
AssigneesKabushiki Kaisha Toshiba, Toshiba Electronic Devices & Storage Corporation
InventorGaku Koizumi
Life of this patent
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Abstract
According to one embodiment, a magnetic head includes a main pole, an auxiliary magnetic pole provided with a write gap in the main pole, a spin torque control element provided in the write gap, a bias current control portion which supplies a bias current to the spin torque control element, and a resistance measuring portion which measures a resistance value of the spin torque control element. The absolute value of a difference between a first resistance value when a bias current is applied with a polarity that magnetization of the spin torque control element is reversed and a second resistance value when the bias current is applied to a reversed polarity of the polarity is less than or equal to 4%.
Claims10
A magnetic head comprising:
- a main pole;
- an auxiliary magnetic pole, with a write gap provided between the auxiliary magnetic pole and the main pole;
- a recording coil wound around a magnetic circuit including the main pole and the auxiliary magnetic pole;
- a recording current control portion which supplies a recording current to the recording coil;
- a spin torque control element provided in the write gap;
- a bias current control portion which supplies a bias current to the spin torque control element;
- and
- a resistance measuring portion which measures a resistance value of the spin torque control element, wherein
- the spin torque control element comprises a magnetization control layer and nonmagnetic conducting layers,
- a condition tF≤λF is established, where tF represents a film thickness of the magnetization control layer and λF represents a spin diffusion length thereof,
- a condition ts≥λs is established, where is represents a film thickness of the nonmagnetic conducting layers and λs represents a spin diffusion length thereof, and
- a variability rate of the resistance value of the spin torque control element that is measured a plurality of times after a write operation with respect to a minimum of the measured resistance value is less than or equal to 4%.
A magnetic recording/reproducing device comprising:
- a magnetic head including
- a main pole,
- an auxiliary magnetic pole., provided with a write gap provided between the auxiliary magnetic pole and the main pole,
- a recording coil provided to be wound around a magnetic circuit including the main pole and the auxiliary magnetic pole;
- a recording current control portion supply a recording current to the recording coil;
- a spin torque control element provided in the write gap,
- a bias current control portion which supplies a bias current to the spin torque control element, and
- a resistance measuring portion which measures a resistance value of the spin torque control element, wherein
- the spin torque control element comprises a magnetization control layer and nonmagnetic conducting layers,
- a condition tF≤λF is established, where tF represents a film thickness of the magnetization control layer and λF represents a spin diffusion length thereof,
- a condition ts≥λs is established, where is represents a film thickness of the nonmagnetic conducting layers and λs represents a spin diffusion length thereof, and
- a variability rate of the resistance value of the spin torque control element that is measured a plurality of times after a write operation with respect to a minimum of the measured resistance value is less than or equal to 4%.
Dependencies are inferred from the claim text.