Sandwich diamond-like carbon overcoat for use in slider designs of proximity recording heads
View Patent ↗A slider is formed of an air bearing surface coated with a wear limiting coating that substantially limits surface wear of the air bearing surface encountered in proximity recording. The wear limiting coating is comprised of a wear inhibiting layer formed on the air bearing surface and a sacrificial layer formed on the wear inhibiting layer. The two coatings of the wear limiting coating have different mechanical properties so that the sacrificial layer is burnished, exposing the wear inhibiting layer. This design substantially limits the surface wear of the air bearing surface typically encountered in proximity recording, resulting in less debris accumulation, which could otherwise adversely affect the performance of the proximity recording head. This self-limiting burnishing action overcomes the flying height variation due to manufacturing tolerances and provides extremely small and uniform magnetic spacing, which greatly enhances the proximity recording. Moreover, the burnishing action also achieves an improved flying stability and a reduction in the altitude sensitivity.
1. A recording head comprising:
a read/write transducer;
a slider having an air bearing surface, the air bearing surface including a center pad;
the center pad including an aft strip that includes the read/write transducer;
a protective layer on the aft strip;
the protective layer comprising a seed layer, a wear-limiting layer, and a sacrificial layer;
the sacrificial layer comprising diamond like carbon (DLC) and having a surface hardness that is less than that of the wear-limiting layer.
2. The recording head of claim 1 wherein the sacrificial layer comprises ethylene DLC.
3. The recording head of claim 2 wherein the wear-limiting layer comprises cathodic-arc DLC.
4. The recording head of claim 1 wherein the wear-limiting layer has a thickness of approximately 10 angstroms.
5. The recording head of claim 1 wherein the sacrificial layer is substantially burnished.
6. The recording head of claim 5 wherein the sacrificial layer has a thickness after burnishing that does not exceed 20 angstroms.
7. The recording head of claim 1 wherein the center pad further comprises a forward region and an aft shallow step region, the aft shallow step region being located between the forward region and the aft strip.
8. The recording head of claim 7 wherein the center pad further comprises a forward shallow step region adjacent to the forward region.
9. A disk drive having an initial phase of operation, the disk drive comprising:
a disk;
a recording head comprising;
a read/write transducer;
a slider having an air bearing surface, the air bearing surface including a center pad;
the center pad including an aft strip that includes the read/write transducer;
a protective layer on the aft strip;
the protective layer comprising a seed layer, a wear-limiting layer, and a sacrificial layer;
the sacrificial layer comprising diamond like carbon (DLC) and having a surface hardness that is less than that of the wear-limiting layer.
10. The disk drive of claim 9 wherein the sacrificial layer comprises ethylene DLC.
11. The disk drive of claim 10 wherein the wear-limiting layer comprises cathodic-arc DLC.
12. The disk drive of claim 9 wherein the wear-limiting layer has a thickness of approximately 10 angstroms.
13. The disk drive of claim 9 wherein the sacrificial layer is substantially burnished during the initial phase of operation to provide an extremely small magnetic spacing between the read/write transducer and a surface of the disk.
14. The disk drive of claim 13 wherein the sacrificial layer [ 306 ] has a thickness after burnishing that does not exceed 20 angstroms.
15. The disk drive of claim 9 wherein the center pad further comprises a forward region and an aft shallow step region, the aft shallow step region being located between the forward region and the aft strip.
16. The disk drive of claim 15 wherein the center pad further comprises a forward shallow step region adjacent to the forward region.