Abstract: According to one embodiment, a magnetic head includes a reproducing portion. The reproducing portion includes first to fourth magnetic portions and a stacked body. The third magnetic portion is provided between the first and second magnetic portions. The fourth magnetic portion is provided between the first and second magnetic portions. A second direction from the third magnetic portion toward the fourth magnetic portion crosses a first direction from the first magnetic portion toward the second magnetic portion. The stacked body is provided between the first and second magnetic portions in the first direction and between the third and fourth magnetic portions in the second direction. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic portion in the first direction, and an intermediate layer provided between the first and second magnetic layers in the first direction.

Abstract: According to one embodiment, a magnetic head includes a reproducing portion. The reproducing portion includes first to fourth magnetic portions and a stacked body. The third magnetic portion is provided between the first and second magnetic portions. The fourth magnetic portion is provided between the first and second magnetic portions. A second direction from the third magnetic portion toward the fourth magnetic portion crosses a first direction from the first magnetic portion toward the second to magnetic portion. The stacked body is provided between the first and second magnetic portions in the first direction and between the third and fourth magnetic portions in the second direction. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic portion in the first direction, and an intermediate layer provided between the first and second magnetic layers in the first direction.

Abstract: According to one embodiment, an oscillator includes a first element. The first element includes first and second magnetic layers, and a first nonmagnetic layer. The first magnetic layer includes first and second magnetic films, and a first nonmagnetic film. The second magnetic film is provided between the second magnetic layer and the first magnetic film. The first nonmagnetic layer is provided between the second magnetic film and the second magnetic layer. An orientation of a first magnetization of the first magnetic film has a reverse component of an orientation of a second magnetization of the second magnetic film. A first magnetic field is applied to the first element. The first element is in a first state when a first current flows in the first element. An electrical resistance of the first element in the first state includes first and second electrical resistances repeating alternately.

Abstract: According to one embodiment, a magnetic head includes a reproducing portion. The reproducing portion includes first to fourth magnetic portions and a stacked body. The third magnetic portion is provided between the first and second magnetic portions. The fourth magnetic portion is provided between the first and second magnetic portions. A second direction from the third magnetic portion toward the fourth magnetic portion crosses a first direction from the first magnetic portion toward the second magnetic portion. The stacked body is provided between the first and second magnetic portions in the first direction and between the third and fourth magnetic portions in the second direction. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic portion in the first direction, and an intermediate layer provided between the first and second magnetic layers in the first direction.

Abstract: According to one embodiment, a magnetic head includes a reproducing portion. The reproducing portion includes first to fourth magnetic portions and a stacked body. The third magnetic portion is provided between the first and second magnetic portions. The fourth magnetic portion is provided between the first and second magnetic portions. A second direction from the third magnetic portion toward the fourth magnetic portion crosses a first direction from the first magnetic portion toward the second magnetic portion. The stacked body is provided between the first and second magnetic portions in the first direction and between the third and fourth magnetic portions in the second direction. The stacked body includes a first magnetic layer, a second magnetic layer provided between the first magnetic layer and the second magnetic portion in the first direction, and an intermediate layer provided between the first and second magnetic layers in the first direction.

Abstract: According to one embodiment, an oscillator includes a first element. The first element includes first and second magnetic layers, and a first nonmagnetic layer. The first magnetic layer includes first and second magnetic films, and a first nonmagnetic film. The second magnetic film is provided between the second magnetic layer and the first magnetic film. The first nonmagnetic layer is provided between the second magnetic film and the second magnetic layer. An orientation of a first magnetization of the first magnetic film has a reverse component of an orientation of a second magnetization of the second magnetic film. A first magnetic field is applied to the first element. The first element is in a first state when a first current flows in the first element An electrical resistance of the first element in the first state includes first and second electrical resistances repeating alternately.

Abstract: According to one embodiment, a microwave sensor includes a first stacked body and a first controller. The first stacked body includes a first magnetic layer, a second magnetic layer, and a first nonmagnetic layer. The first nonmagnetic layer is provided between the first magnetic layer and the second magnetic layer. The first controller is electrically connected to the first magnetic layer and the second magnetic layer. The first controller is configured to supply a current to the first stacked body and is configured to sense a value corresponding to a first electrical resistance between the first magnetic layer and the second magnetic layer. A second magnetization of the second magnetic layer is aligned with a first direction from the first magnetic layer toward the second magnetic layer. The value corresponding to the first electrical resistance changes according to a microwave.

Abstract: According to an embodiment, a computing apparatus includes spin torque oscillators, an interaction unit, a variable direct-current supply device, and a measuring unit. The interaction unit controls an interaction between the spin torque oscillators. The variable direct-current supply device supplies a current to induce oscillations of the spin torque oscillators. The measuring unit measures AC signals obtained from the spin torque oscillators.

Abstract: A magnetic recording and reproducing apparatus for recording and reproducing bit information comprising a magnetic head having a spin torque oscillator configured to readout bit information which is recorded on a magnetic recording medium, a detector configured to detect amplitude of a first signal, the first signal which is to reproduce the bit information, and a controller configured to control the magnetic head so as to read the bit information recorded on the magnetic recording medium when the amplitude of the first signal detected by the detector is smaller than a predetermined value.

Abstract: A magnetic recording and reproducing apparatus for recording and reproducing bit information comprising a magnetic head having a spin torque oscillator configured to readout bit information which is recorded on a magnetic recording medium, a detector configured to detect amplitude of a first signal, the first signal which is to reproduce the bit information, and a controller configured to control the magnetic head so as to read the bit information recorded on the magnetic recording medium when the amplitude of the first signal detected by the detector is smaller than a predetermined value.

Abstract: According to an embodiment, a computing apparatus includes spin torque oscillators, an interaction unit, a variable direct-current supply device, and a measuring unit. The interaction unit controls an interaction between the spin torque oscillators. The variable direct-current supply device supplies a current to induce oscillations of the spin torque oscillators. The measuring unit measures AC signals obtained from the spin torque oscillators.

Abstract: A magnetic disk apparatus includes a computing unit that obtains data to be recorded on a magnetic disk and computes an intermediate bit length based on a longest bit length and a shortest bit length of bit lengths of the obtained data; an adjusting unit that adjusts a strength of a recording current for recording the obtained data based on a difference between the intermediate bit length and a bit length of the obtained data; and a recording unit that repeatedly detects an error rate for recording data by using the adjusted recording current while narrowing down a track width on the magnetic disk and records the obtained data with a track width corresponding to an error rate detected immediately before an error rate that is detected to be equal to or greater than a predetermined value.

Abstract: According to one embodiment, a magnetic disk drive uses a patterned medium on which data tracks having a recording layer and grooves having no recording layer as a disk. The magnetic disk drive includes a correction unit which corrects the head center position of a write head so that a head edge portion on the side to which the top edge of the write head is tilted falls within or substantially falls within a groove on the side to which the top edge of the write head is tilted.

Abstract: A magnetic disk apparatus includes a computing unit that obtains data to be recorded on a magnetic disk and computes an intermediate bit length based on a longest bit length and a shortest bit length of bit lengths of the obtained data; an adjusting unit that adjusts a strength of a recording current for recording the obtained data based on a difference between the intermediate bit length and a bit length of the obtained data; and a recording unit that repeatedly detects an error rate for recording data by using the adjusted recording current while narrowing down a track width on the magnetic disk and records the obtained data with a track width corresponding to an error rate detected immediately before an error rate that is detected to be equal to or greater than a predetermined value.

Abstract: In a write-once type storage apparatus, a head having a recording element and a recording element is supported at the leading end of a rotary actuator, and information written once in a disk medium by the head is then reproduced. A write processing unit writes information sequentially from a track giving the largest yaw angle of the actuator in the recording track area of the disk medium to a track giving a yaw angle of 0°. For example, the write processing unit writes information sequentially from the outermost track of the disk medium toward a track giving a yaw angle of 0°, and then, writes information sequentially from the innermost track to a track giving a yaw angle of 0°. A read processing unit reads out information write-once-written in the disk medium from a track of a larger yaw angle toward a track of a smaller yaw angle.

Abstract: A determining unit retrieves status information relating to recording or reproducing data on the magnetic disk, and determines whether to re-record data recorded in a recording area on the magnetic disk based on the retrieved status information. When the determining unit determines to re-record first data recorded in a first recording area, a re-recording unit re-records at least one of the first data and second data recorded in a second recording area near the first recording area on the magnetic disk.

Abstract: A data writing method to write data on a disk in a disk device. The data is written in one radial direction. The method includes detecting a first deviation amount from a center in a current track and sector in the direction of a track on which data was previously written. A second deviation amount from the center in the current track and sector in the direction of a track on which data will be subsequently written is also detected. Data is written on the current track when the first deviation amount is equal to or smaller than a first threshold and the second deviation amount is equal to or smaller than a second threshold.

Abstract: A magnetic head having a recording head portion for recording information at an arbitrary position on a magnetic recording surface of a recording medium and also having a reproducing head portion containing a reproducing head element for reproducing the information recorded at the arbitrary position on the magnetic recording surface forms a reproducing head element, the shape of which is curved, being made after a curved shape of a magnetization pattern recorded at the arbitrary position of the recording medium. Due to the foregoing, a shape of the lead gap formed between the reproducing head element and the magnetic recording surface of the recording medium is made to substantially agree with the shape of the magnetization pattern. On the other hand, a disk apparatus having a reproducing head element is provided in which the shape of the lead gap is made to substantially agree with the shape of the magnetization pattern.

Abstract: A reproducing head including a read element, first and second electrodes provided at the opposite ends of the read element, a ground electrode provided between the first and second electrodes, a first constant current circuit for passing a first constant current between the first electrode and the ground electrode, and a second constant current circuit for passing a second constant current between the second electrode and the ground electrode. The reproducing head further includes a computing unit connected to the first and second electrodes for synthesizing an output from the first electrode and an output from the second electrode, and a storing unit having a table showing the relation between a synthetic value computed by the computing unit and the outputs from the first and second electrodes.

Abstract: A magnetic disk drive includes an actuator arm, a suspension fixed to a tip end of the actuator arm, and a head slider having at least two electromagnetic transducers mounted at a tip end of the suspension. The head slider has a first electromagnetic transducer inclined in a direction in which the inner side face side is nearer to an air outflow end than a central portion thereof, and a second electromagnetic transducer inclined in a direction in which the outer side face side is nearer to the air outflow side than the central portion thereof. A controller performs changeover control such that an inner side data region of a magnetic disk is taken charge of by the first electromagnetic transducer while an outer side data region is taken charge of by the second electromagnetic transducer.