Base for magnetic recording medium, magnetic recording medium, and magnetic storage apparatus
A base for a magnetic recording medium, includes an aluminum alloy substrate, and a nickel alloy film provided on at least one principal surface of the aluminum alloy substrate. The nickel alloy film includes Mo in a range of 0.5 wt % to 3 wt %, P in a range of 11 wt % to 15 wt %, and Al in a range of 0.001 wt % to 0.1 wt %.
1. A base for a magnetic recording medium, comprising:
an aluminum alloy substrate; and
a nickel alloy film provided on at least one principal surface of the aluminum alloy substrate, wherein
the nickel alloy film includes Mo in a range of 0.5 wt % to 3 wt %, P in a range of 11 wt % to 15 wt %, and Al in a range of 0.001 wt % to 0.1 wt %,
a height of a minute surface waviness generated on a surface of the nickel alloy film is 0.100 nm or less when the base is heated under a heating condition of 20 minutes at 320° C. during evaluation of the base, and
a number of micro-bulges generated at the surface of the nickel alloy film and having a height of 1 nm or greater is less than 0.050 bulges/cm 2 when the base is heated under a heating condition of 20 minutes at 320° C. during evaluation of the base.
2. The base for the magnetic recording medium as claimed in claim 1 , wherein
the nickel alloy film is a film of a NiMoP-based alloy including additional elements, with Ni as a remainder, and
the additional elements include first additional elements including Mo, P, and Al.
3. The base for the magnetic recording medium as claimed in claim 2 , wherein
the additional elements further include second additional elements including one or more elements selected from a group consisting of Cr, Zn, Ba, and Pb, and
a content of the second additional elements is less than 0.001 wt %.
4. A magnetic recording medium comprising:
the base for the magnetic recording medium according to claim 3 ; and
a magnetic layer, provided on the nickel alloy film of the base, and including a FePt alloy or a CoPt alloy having a L1 0 crystal structure.
5. A magnetic storage apparatus comprising:
the magnetic recording medium according to claim 4 ; and
a magnetic head configured to write information to and read information from the magnetic recording medium.
6. A magnetic recording medium comprising:
the base for the magnetic recording medium according to claim 2 ; and
a magnetic layer, provided on the nickel alloy film of the base, and including a FePt alloy or a CoPt alloy having a L1 0 crystal structure.
7. A magnetic storage apparatus comprising:
the magnetic recording medium according to claim 6 ; and
a magnetic head configured to write information to and read information from the magnetic recording medium.
8. A magnetic recording medium comprising:
the base for the magnetic recording medium according to claim 1 ; and
a magnetic layer, provided on the nickel alloy film of the base, and including a FePt alloy or a CoPt alloy having a L1 0 crystal structure.
9. A magnetic storage apparatus comprising:
the magnetic recording medium according to claim 8 ; and
a magnetic head configured to write information to and read information from the magnetic recording medium.
10. The magnetic storage apparatus as claimed in claim 9 , wherein the nickel alloy film of the base of the magnetic recording medium has a thickness in a range or 5 μm to 20 μm.
11. The magnetic recording medium as claimed in claim 8 , wherein the nickel alloy film of the base has a thickness in a range or 5 μm to 20 μm.
12. The base for the magnetic recording medium as claimed in claim 1 , wherein the nickel alloy film has a thickness in a range or 5 μm to 20 μm.