Magnetic recording medium with magnesium-titanium oxide (MTO) layer formed using pulsed direct current sputter deposition
Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium that has a magnetic recording layer on a MgO—TiO (MTO) underlayer, where the MTO underlayer is formed using pulsed DC sputtering and has less than 50 mol % of TiO. By providing an MTO layer with less than 50 mol % of TIO, smaller grain sizes may be achieved in the magnetic recording layer, providing for higher areal densities. In some embodiments, a second MTO underlayer is provided, which is formed using non-pulsed DC sputtering and has 50 mol % of TiO. That is, a dual-layer MTO underlayer may be provided with, e.g., an MgO-30TiO layer atop an MgO-50TiO layer.
1. A magnetic recording medium comprising:
a substrate;
a heatsink layer on the substrate, the heatsink layer comprising Cr;
a thermal resistive layer on the heatsink layer, the thermal resistive layer comprising RuAlTiO 2 ;
an underlayer on the thermal resistive layer, wherein the underlayer comprises a first MgO—TiO layer with less than 50 mol % of TiO and a second MgO—TiO layer comprising 50 or more mol % of TiO; and
a magnetic recording layer comprising FePt on the underlayer.
2. The magnetic recording medium of claim 1 , wherein the thermal resistive layer is etched to reduce roughness.
3. The magnetic recording medium of claim 1 , wherein the first MgO—TiO layer comprises TiO in the range of 15 mol % to 45 mol %, inclusive, and wherein the second MgO—TiO layer comprises TiO in the range of 55 mol % to 85 mol %, inclusive.
4. The magnetic recording medium of claim 1 , wherein the first MgO—TiO layer comprises TiO in the range of 25 mol % to 35 mol %, inclusive, and wherein the second MgO—TiO layer comprises TiO in the range of 65 mol % to 75 mol %, inclusive.
5. The magnetic recording medium of claim 1 , wherein the first MgO—TiO layer comprises 30 mol % TiO and the second MgO—TiO layer comprises 70 mol % TiO.
6. The magnetic recording medium of claim 1 , wherein the underlayer has a thickness in the range of 2.0 nanometers (nm) to 3.5 nm, inclusive.
7. The magnetic recording medium of claim 1 , further comprising an adhesion layer, a soft underlayer (SUL), and a seed layer, in that order, between the substrate and the heatsink layer, wherein the adhesion layer comprises NiTa, the seed layer comprises RuAl, and further comprising a capping layer comprising CoFe on the magnetic recording layer and a carbon overcoat (COC) on the capping layer.
8. The magnetic recording medium of claim 1 , wherein the underlayer is directly on the thermal resistive layer and the thermal resistive layer is directly on the heatsink layer.
9. A data storage device comprising:
a slider comprising a magnetic head; and
the magnetic recording medium of claim 1 ,
wherein the slider is configured to write information, using localized heating, to the magnetic recording layer of the magnetic recording medium.
10. A method for manufacturing a magnetic recording medium, the method comprising:
providing a substrate;
providing a heatsink layer on the substrate, the heatsink layer comprising Cr;
providing a thermal resistive layer on the heatsink layer, the thermal resistive layer comprising RuAlTiO 2 ;
providing an underlayer on the thermal resistive layer, wherein the underlayer comprises a first MgO—TiO layer with less than 50 mol % of TiO and a second MgO—TiO layer comprising 50 or more mol % of TiO; and
providing a magnetic recording layer comprising FePt on the underlayer.
11. The method of claim 10 , wherein the thermal resistive layer is etched to reduce roughness.
12. The method of claim 10 , wherein the first MgO—TiO layer comprises TiO in the range of 15 mol % to 45 mol %, inclusive, and wherein the second MgO—TiO layer comprises TiO in the range of 55 mol % to 85 mol %, inclusive.
13. The method of claim 10 , wherein the first MgO—TiO layer comprises 30 mol % TiO and the second MgO—TiO layer comprises 70 mol % TiQ.
14. The method of claim 10 , wherein the first MgO—TiO layer is sputtered using a pulsed direct current (DC) and wherein the second MgO—TiO layer is sputtered using a non-pulsed direct current (DC).
15. A magnetic recording medium formed using a process comprising:
providing a substrate;
providing a heatsink layer on the substrate, the heatsink layer comprising Cr;
forming a thermal resistive layer on the heatsink layer, the thermal resistive layer comprising RuAlTiO 2 ;
forming an underlayer on the heatsink layer, wherein the underlayer comprises a first MgO—TiO layer with less than 50 mol % of TiO and a second MgO—TiO layer comprising 50 or more mol % of TiO; and
providing a magnetic recording layer comprising FePt on the underlayer.
16. The magnetic recording medium formed using the process of claim 15 , wherein the first MgO—TiO layer comprises 30 mol % TiO and the second MgO—TiO layer comprises 70 mol % TiO.
17. The magnetic recording medium of claim 1 , wherein the first MgO—TiO layer is on the thermal resistive layer and the second MgO—TiO layer is on the first MgO—TiO layer.
18. The magnetic recording medium of claim 1 , wherein the second MgO—TiO layer is on the thermal resistive layer and the first MgO—TiO layer is on the second MgO—TiO layer.
19. The magnetic recording medium of claim 1 , wherein the first MgO—TiO layer is sputtered using a pulsed direct current (DC) and wherein the second MgO—TiO layer is sputtered using a non-pulsed direct current (DC).
20. The magnetic recording medium formed using the process of claim 15 , wherein the first MgO—TiO layer is formed on the thermal resistive layer and the second MgO—TiO layer is formed on the first MgO—TiO layer.
21. The magnetic recording medium formed using the process of claim 15 , wherein the second MgO—TiO layer is formed on the thermal resistive layer and the first MgO—TiO layer is formed on the second MgO—TiO layer.
22. The magnetic recording medium formed using the process of claim 15 , wherein the first MgO—TiO layer is formed using pulsed direct current (DC) sputtering and wherein the second MgO—TiO layer is formed using a non-pulsed direct current (DC) sputtering.