Magnetic recording device supplied with varying recording current
According to one embodiment, a magnetic recording device includes a magnetic head, a first electrical circuit, and a second electrical circuit. The magnetic head includes a magnetic pole, a first shield, a conductive member electrically connecting the magnetic pole and the first shield and being provided between the magnetic pole and the first shield, and a coil. The first electrical circuit is configured to supply a first current to the magnetic pole, the conductive member, and the first shield. The second electrical circuit is configured to supply a recording current to the coil. A recording magnetic field is generated from the magnetic pole. The recording magnetic field corresponds to the recording current. A rise time of the recording current is not less than 65% of a shortest bit length.
1. A magnetic recording device, comprising:
a magnetic head including
a magnetic pole,
a first shield,
a conductive member electrically connecting the magnetic pole and the first shield and being provided between the magnetic pole and the first shield, and
a coil;
a first electrical circuit configured to perform at least a first operation and a second operation, the first operation supplying a first current to the magnetic pole, the conductive member, and the first shield, the second operation not supplying the first current to the magnetic pole, the conductive member, and the first shield; and
a second electrical circuit configured to supply a recording current to the coil,
a recording magnetic field being generated from the magnetic pole,
the recording magnetic field corresponding to the recording current,
wherein the second electrical circuit sets a first rise time of the recording current in the first operation to be longer than a second rise time of the recording current in the second operation.
2. The device according to claim 1 , wherein a difference between the first rise time and the second rise time is 80 picoseconds or more.
3. The device according to claim 1 , wherein a rise time of the recording current in the first operation is not less than 65% of a time of 1 bit.
4. The device according to claim 1 , wherein
in the second operation, a current does not flow in the magnetic pole, the conductive member, and the first shield, or
in the second operation, a current flowing in the magnetic pole, the conductive member, and the first shield is smaller than the first current.
5. The device according to 1 , wherein
the conductive member includes:
a magnetic layer;
a first conductive layer contacting the magnetic pole and the magnetic layer, being provided between the magnetic pole and the magnetic layer, including one of a first material or a second material, and being nonmagnetic; and
a second conductive layer contacting the magnetic layer and the first shield, being provided between the magnetic layer and the first shield, including the other of the first material or the second material, and being nonmagnetic, the first material includes at least one selected from the group consisting of Ta, Pt, W, Ru, Mo, Ir, Rh, and Pd, and
the second material includes at least one selected from the group consisting of Cu, Ag, and Au.
6. The device according to claim 1 , wherein
the conductive member includes:
a first magnetic layer;
a second magnetic layer; and
an intermediate layer provided between the first magnetic layer and the second magnetic layer, the intermediate layer being nonmagnetic, and
a high frequency magnetic field is generated from the conductive member in the first operation.
7. The device according to claim 1 , further comprising a magnetic recording medium, information being recorded in the magnetic recording medium by the magnetic head.
8. The device according to claim 1 , wherein
the conductive member includes:
a first magnetic layer;
a second magnetic layer; and
an intermediate layer provided between the first magnetic layer and the second magnetic layer, the intermediate layer being nonmagnetic.
9. The device according to claim 8 , wherein a high frequency magnetic field is generated from the conductive member.
10. The device according to claim 8 , wherein the intermediate layer includes at least one selected from the group consisting of Cu, Au, and Ag.
11. The device according to claim 8 , wherein
the first magnetic layer includes one of a first magnetic material or a second magnetic material,
the second magnetic layer includes the other of the first magnetic material or the second magnetic material,
the first magnetic material includes at least one selected from the group consisting of an FeCo alloy and a Heusler alloy, and
the second magnetic material includes at least one selected from the group consisting of a stacked film including a CoPt alloy, an FePt alloy, Co, and Pd and a stacked film including Co and Pt.
12. The device according to claim 11 , wherein
the first magnetic layer includes the first magnetic material,
the second magnetic layer includes the second magnetic material, and
the first current has an orientation from the second magnetic layer toward the first magnetic layer.