Patent classifications
G11B5/35
Data storage device using windowed delta-sigma analog-to-digital converter in digital current control loop
A data storage device is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The data storage device further comprises control circuitry comprising a digital current control loop including a windowed delta-sigma analog-to-digital converter (ADC) configured to control the VCM. A vibration of the data storage device is measured, and at least one of a gain or a window of the windowed delta-sigma ADC is configured based on the measured vibration.
Data storage device using windowed delta-sigma analog-to-digital converter in digital current control loop
A data storage device is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The data storage device further comprises control circuitry comprising a digital current control loop including a windowed delta-sigma analog-to-digital converter (ADC) configured to control the VCM. A vibration of the data storage device is measured, and at least one of a gain or a window of the windowed delta-sigma ADC is configured based on the measured vibration.
DATA STORAGE DEVICE USING WINDOWED DELTA-SIGMA ANALOG-TO-DIGITAL CONVERTER IN DIGITAL CURRENT CONTROL LOOP
A data storage device is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The data storage device further comprises control circuitry comprising a digital current control loop including a windowed delta-sigma analog-to-digital converter (ADC) configured to control the VCM. A vibration of the data storage device is measured, and at least one of a gain or a window of the windowed delta-sigma ADC is configured based on the measured vibration.
DATA STORAGE DEVICE USING WINDOWED DELTA-SIGMA ANALOG-TO-DIGITAL CONVERTER IN DIGITAL CURRENT CONTROL LOOP
A data storage device is disclosed comprising a voice coil motor (VCM) configured to actuate a head over a disk. The data storage device further comprises control circuitry comprising a digital current control loop including a windowed delta-sigma analog-to-digital converter (ADC) configured to control the VCM. A vibration of the data storage device is measured, and at least one of a gain or a window of the windowed delta-sigma ADC is configured based on the measured vibration.
Magnetic recording device and magnetic head
According to one embodiment, a magnetic recording device includes a magnetic head, a first circuit, and a second circuit. The magnetic head includes a magnetic pole, a first shield, a stacked body provided between the magnetic pole and the first shield, a first terminal electrically connected to the magnetic pole, a second terminal electrically connected to the first shield, and a coil. The first circuit is electrically connected to the first terminal and the second terminal. The second circuit is electrically connected to the coil. The first circuit performs at least a first operation. In the first operation, the first circuit supplies a first current to a current path between the first and second terminals when the second circuit supplies a recording current to the coil. The first current is smaller than a second current. The second current causes an electrical resistance of the current path to oscillate.
Magnetic recording device and magnetic head
According to one embodiment, a magnetic recording device includes a magnetic head, a first circuit, and a second circuit. The magnetic head includes a magnetic pole, a first shield, a stacked body provided between the magnetic pole and the first shield, a first terminal electrically connected to the magnetic pole, a second terminal electrically connected to the first shield, and a coil. The first circuit is electrically connected to the first terminal and the second terminal. The second circuit is electrically connected to the coil. The first circuit performs at least a first operation. In the first operation, the first circuit supplies a first current to a current path between the first and second terminals when the second circuit supplies a recording current to the coil. The first current is smaller than a second current. The second current causes an electrical resistance of the current path to oscillate.
Microwave-assisted magnetic recording (MAMR) write head with compensation for DC shunting field
A microwave-assisted magnetic recording (MAMR) write head has a spin-torque oscillator (STO) and a ferromagnetic compensation layer between the write pole and trailing shield. The compensation layer is separated from a free layer by a nonmagnetic barrier layer that prevents spin-polarized electrons from the free layer from reaching the compensation layer. The compensation layer may be located between the write pole and the free layer. Electrons become spin-polarized by the compensation layer and are reflected back from the write pole across a nonmagnetic spacer layer. This causes the magnetization of the compensation layer to flip and become antiparallel to the magnetization of the free layer. The compensation layer thus generates a DC offset field that compensates for the negative effect of the DC shunting field from the free layer.
Microwave-assisted magnetic recording (MAMR) write head with compensation for DC shunting field
A microwave-assisted magnetic recording (MAMR) write head has a spin-torque oscillator (STO) and a ferromagnetic compensation layer between the write pole and trailing shield. The compensation layer is separated from a free layer by a nonmagnetic barrier layer that prevents spin-polarized electrons from the free layer from reaching the compensation layer. The compensation layer may be located between the write pole and the free layer. Electrons become spin-polarized by the compensation layer and are reflected back from the write pole across a nonmagnetic spacer layer. This causes the magnetization of the compensation layer to flip and become antiparallel to the magnetization of the free layer. The compensation layer thus generates a DC offset field that compensates for the negative effect of the DC shunting field from the free layer.
MAMR recording head with high damping trailing shield seed layer
A microwave assisted magnetic recording (MAMR) write head includes a main pole and a trailing shield. A spin torque oscillator device is disposed between the main pole and the trailing shield. The spin torque oscillator device includes a free layer. A trailing shield hot seed layer is disposed between the spin torque oscillator device and the trailing shield. The trailing shield hot seed layer includes a magnetic material doped with a rare earth element. In certain embodiments, the trailing shield hot seed layer includes the rare earth element in an atomic percent content from about 2% to about 10% atomic percent. In certain embodiments, the trailing shield hot seed layer has an intrinsic damping from about 0.02 to about 0.2.
MAMR recording head with high damping trailing shield seed layer
A microwave assisted magnetic recording (MAMR) write head includes a main pole and a trailing shield. A spin torque oscillator device is disposed between the main pole and the trailing shield. The spin torque oscillator device includes a free layer. A trailing shield hot seed layer is disposed between the spin torque oscillator device and the trailing shield. The trailing shield hot seed layer includes a magnetic material doped with a rare earth element. In certain embodiments, the trailing shield hot seed layer includes the rare earth element in an atomic percent content from about 2% to about 10% atomic percent. In certain embodiments, the trailing shield hot seed layer has an intrinsic damping from about 0.02 to about 0.2.