Heat-assisted magnetic recording device capable of providing negative electrical potential at NFT
A heat-assisted magnetic recording (HAMR) hard disk drive has a gas-bearing slider supporting a near-field transducer (NFT) and a NFT temperature sensor (NTS). An optional first IVC circuitry may provide a bias voltage to the slider body to assure substantially zero electrical potential between the slider body and the disk to minimize slider-disk contact and lubrication pick-up. A second IVC circuitry operates independently of the first IVC circuitry and provides a negative bias voltage to the NTS (and the connected NFT) relative to the disk to minimize the adverse effects of excessive heating on the NFT.
1. A heat-assisted magnetic recording (HAMR) disk drive comprising:
a rotatable magnetic recording disk;
a gas-bearing slider maintained over the surface of the disk when the disk is rotating;
a write head on the slider comprising a main pole;
an optical waveguide on the slider for receipt of laser radiation;
a near-field transducer (NFT) on the slider for optical coupling with the waveguide;
a NFT temperature sensor (NTS) coupled to the NFT;
interface voltage control circuitry coupled to the NFT, the interface voltage control circuitry being adapted to provide a negative electrical potential at the NFT relative to the disk and adapted to apply a common mode voltage to the NTS, wherein the interface voltage control circuitry comprises a source for generating a reference current through a pair of resistors having substantially equal resistance values, and wherein the interface voltage control circuitry is further adapted to apply said common mode voltage between the two resistors of said pair.
2. A heat-assisted magnetic recording (HAMR) disk drive comprising:
a rotatable magnetic recording disk;
a gas-bearing slider maintained over the surface of the disk when the disk is rotating;
a write head on the slider comprising a main pole;
an optical waveguide on the slider for receipt of laser radiation;
a near-field transducer (NFT) on the slider for optical coupling with the waveguide; and
interface voltage control circuitry coupled to the NFT, the interface voltage control circuitry being adapted to provide a negative electrical potential at the NFT relative to the disk, wherein the interface voltage control circuitry coupled to the NFT is a second interface voltage control circuitry (IVC2) and further comprising a first interface voltage control circuitry (IVC1) electrically coupled to the body of the slider and adapted to assure substantially zero electrical potential between the slider body and the disk.
3. The disk drive of claim 2 wherein the slider further comprises a coil coupled to the write head, a read head, a heater and an embedded contact sensor (ECS), and wherein the IVC1 is electrically coupled to one of said coil, read head, heater and ECS.
4. The disk drive of claim 3 wherein the IVC1 is electrically coupled to the ECS and is further adapted to apply a common mode voltage to the ECS.
5. A heat-assisted magnetic recording (HAMR) disk drive comprising:
a rotatable magnetic recording disk;
a gas-bearing slider maintained over the surface of the disk when the disk is rotating;
a write head on the slider comprising a main pole, a return pole and an electrical coil for generating a write current;
an optical waveguide on the slider for receipt of laser radiation;
a near-field transducer (NFT) on the slider for optical coupling with the waveguide;
a NFT temperature sensor (NTS) on the slider and coupled to the NFT;
a read head on the slider;
a first interface voltage control circuitry (IVC1) electrically coupled to one of said coil and read head, the IVC1 being adapted to provide substantially zero electrical potential between the slider and the disk; and
second interface voltage control circuitry (IVC2) coupled to the NTS and adapted to provide a negative electrical potential at the NTS relative to the disk.
6. The disk drive of claim 5 wherein the IVC2 is further adapted to apply a common mode voltage to the NTS.
7. The disk drive of claim 6 wherein the IVC2 comprises a source for generating a reference current through a pair of resistors having substantially equal resistance values, and wherein the IVC2 is further adapted to apply said common mode voltage between the two resistors of said pair.
8. The disk drive of claim 5 wherein each of the IVC1 and IVC2 is further adapted to provide a programmable voltage.
9. The disk drive of claim 5 further comprising a heater on the slider and an embedded contact sensor (ECS) on the slider, and wherein the IVC1 is electrically coupled to the ECS.
10. The disk drive of claim 9 wherein the IVC1 is adapted to apply a common mode voltage to the ECS.
11. The disk drive of claim 1 wherein the interface voltage control circuitry is further adapted to provide a negative electrical potential at the NTS relative to the disk.
12. The disk drive of claim 2 further comprising a NFT temperature sensor (NTS) coupled to the NFT.
13. The disk drive of claim 12 wherein the interface voltage control circuitry is further adapted to provide a negative electrical potential at the NTS relative to the disk.
14. The disk drive of claim 12 wherein the interface voltage control circuitry is further adapted to apply a common mode voltage to the NTS.