Magnetic head having durability against static electricity with modified time constant
View Patent ↗Embodiments of the invention provide a read head which is implemented in a magnetic disk drive that supports a high recording density and a high transfer rate and is excellent in static electricity durability. In one embodiment, a magnetic head wherein a charge diffuses from a read element to a slider at a time constant of about 100 ms or less.
1. A magnetic head comprising:
a slider;
a base alumina formed on the slider;
a lower magnetic shield formed on the base alumina;
a read element formed on the lower magnetic shield;
an electrode for applying a current to the read element;
an upper magnetic shield formed on the electrode; and
a protection film formed on an air bearing surface;
wherein a charge diffuses from the read element to the slider at a time constant between about 100 ms and 1 ms.
2. The magnetic head according to claim 1 , wherein the protection film contains carbon.
3. The head suspension assembly according to claim 1 , wherein a resistance between the electrode and the suspension is in the range of about 10 6 Ω to 10 11 Ω, and wherein the protection film is between about 3 nm and about 8 nm.
4. The magnetic head according to claim 1 , wherein the resistance value between the read element and the slider is determined depending on a resistance value Rr between the electrode and the upper and lower magnetic shields, a resistance value R 1 between the upper and lower magnetic shields and the slider, and a resistance value Rc of the protection film on the air bearing surface.
5. The magnetic head according to claim 1 , wherein the base alumina has a film thickness of about 0.7 micrometers.
6. The magnetic head according to claim 1 , wherein the protection film comprises a 1 nm-thick Si underlayer and a 2 nm-thick CAC carbon film.
7. The magnetic head according to claim 1 , wherein the lower magnetic shield has a thickness of about 3 μm.
8. A head suspension assembly comprising:
a read element for reading information from a magnetic disk;
an electrode for applying a current to the read element;
a slider having the read element and the electrode; and
a suspension for supporting the slider;
wherein a charge diffuses from the read element to the suspension at a time constant between about 100 ms and 1 ms.
9. The head suspension assembly according to claim 8 , further comprising a protection film formed on an air bearing surface, wherein a resistance between the electrode and the suspension is in the range of about 10 6 Ω to 10 11 Ω, and wherein the protection film is between about 3 nm and about 8 nm.
10. The head suspension assembly according to claim 8 , wherein
the suspension has a wiring connected to an electric ground, and
a resistance between the electrode and the ground wiring is in the range of about 10 6 Ω to 10 11 Ω.
11. The head suspension assembly according to claim 8 , further comprising:
a base alumina formed on the slider;
a lower magnetic shield formed on the base alumina, wherein the read element is formed on the lower magnetic shield;
an upper magnetic shield formed on the electrode; and
a protection film formed on an air bearing surface.
12. The head suspension assembly according to claim 11 , wherein the protection film contains carbon.
13. The head suspension assembly according to claim 11 , wherein the base alumina has a film thickness of about 0.7 micrometers.
14. The head suspension assembly according to claim 11 , wherein the protection film comprises a 1 nm-thick Si underlayer and a 2 nm-thick CAC carbon film.
15. The head suspension assembly according to claim 11 , wherein the lower magnetic shield has a thickness of about 3 μm.