Magnetic thin film media with a bi-layer structure of CrTi/Nip
View Patent ↗A thin film magnetic media structure with a bi-layer structure of amorphous chromium titanium (CrTi) followed by an amorphous layer of nickel phosphorus (NiP) is disclosed. After the NiP has been deposited it is exposed to oxygen to form an oxidized surface. Preferably the underlayer is deposited directly onto the oxidized NiP surface. The bi-layer structure of CrTi/NiP promotes excellent in-plane crystallographic orientation in the cobalt alloy magnetic layer(s) and allows an ultra-thin chromium underlayer to be used which provides better control over grain size and distribution. When the CrTi/NiP bi-layer structure is combined with a circumferentially textured substrate, preferably glass, a high Mrt orientation ratio (OR) results.
1. A magnetic thin film storage medium comprising:
a substrate;
a layer of amorphous CrTi deposited onto the substrate;
a layer of amorphous NiP deposited onto ever the layer of CrTi;
at least one underlayer over the layer of amorphous NIP; and
at least one magnetic layer over the underlayer.
2. The magnetic thin film storage medium of claim 1 wherein the layer of amorphous NiP has an oxidized surface formed after the layer of amorphous NiP was deposited.
3. The magnetic thin film storage medium of claim 2 wherein the underlayer is chromium that is deposited onto the oxidized surface of the layer of amorphous NiP.
4. The magnetic thin film storage medium of claim 1 wherein the substrate is circumferentially textured glass.
5. The magnetic thin film storage medium of claim 1 wherein the underlayer is chromium or an alloy of chromium.
6. The magnetic thin film storage medium of claim 1 wherein the layer of amorphous CrTi is approximately from 45 to 55 at. % titanium.
7. The magnetic thin film storage medium of claim 1 wherein the layer of amorphous NiP is approximately from 15 to 25 at. % phosphorus.
8. A disk drive comprising:
a magnetic transducer including a read and a write head;
a spindle; and
a magnetic thin film disk mounted on the spindle, the magnetic thin film disk including a layer of amorphous CrTi followed by a layer of amorphous NiP deposited onto the layer of amorphous CrTi and at least one magnetic layer.
9. The disk drive of claim 8 wherein the layer of amorphous NiP has an oxidized surface formed after the layer of amorphous NiP was deposited.
10. The disk drive of claim 9 wherein the underlayer is chromium or a chromium alloy and is deposited onto the oxidized surface of the layer of amorphous NiP.
11. The disk drive of claim 9 wherein the substrate is circumferentially textured glass.
12. The disk drive of claim 9 wherein the layer of amorphous CrTi is approximately from 45 to 55 at. % titanium.
13. The disk drive of claim 9 wherein the layer of amorphous NiP is approximately from 15 to 25 at. % phosphorus.
14. A method of fabricating a magnetic thin film storage medium comprising the steps of:
depositing a thin film of amorphous CrTi on a substrate; and
depositing a thin film of NiP onto the thin film of CrTi.
15. The method of claim 14 further comprising the step of oxidizing an exposed surface of the thin film of NiP.
16. The method of claim 15 further comprising the step of depositing a thin film chromium underlayer onto the thin film of amorphous NiP.
17. The method of claim 15 wherein the substrate is circumferentially textured glass.
18. The method of claim 15 further comprising the step of depositing a thin film chromium alloy underlayer onto the thin film of amorphous NiP.
19. The method of claim 15 wherein the thin film of CrTi is approximately from 45 to 55 at. % titanium.
20. The method of claim 15 wherein the thin film of NIP is approximately from 15 to 25 at. % phosphorus.