Magnetic recording medium and magnetic storage apparatus
A magnetic recording medium includes a seed layer made of one of AlRu and AlV, a magnetic recording layer made of a CoCr alloy, and an underlayer made of the other of AlRu and AlV, where the underlayer is disposed between the seed layer and the magnetic recording layer.
1. A magnetic recording medium comprising:
a seed layer made of one of AlRu and AlV;
a magnetic recording layer made of a CoCr alloy; and
an underlayer made of the other of AlRu and AlV, said underlayer being disposed between the seed layer and the magnetic recording layer.
2. The magnetic recording medium as claimed in claim 1 , wherein a total thickness of said seed layer and said underlayer is in a range of approximately 20 nm to 70 nm.
3. The magnetic recording medium as claimed in claim 1 , wherein said seed layer has a thickness in a range of approximately 5 nm to 50 nm, and said underlayer has a thickness in a range of approximately 2 nm to 50 nm.
4. The magnetic recording medium as claimed in any of claim 1 , wherein said seed layer is reactively sputtered in an Ar+N 2 or Ar+O 2 gas mixture at N 2 or O 2 partial pressure P N,O =1% to 20%.
5. The magnetic recording medium as claimed in claim 1 , further comprising:
a substrate made of glass or Al,
said seed layer being disposed on said substrate.
6. The magnetic recording medium as claimed in claim 5 , wherein said substrate is mechanically textured.
7. The magnetic recording medium as claimed in claim 1 , wherein the said magnetic recording layer is made up of a single magnetic layer or a synthetic ferrimagnetic structure, said synthetic ferrimagnetic structure being made up of at least two antiferromagnetically coupled CoCr alloy magnetic layers, wherein c-axes of CoCr alloy magnetic layers are significantly parallel to a film plane thereof such that a ratio h≦0.15 stands, where h=Hc⊥/Hc, Hc⊥ denotes perpendicular coercivity, and Hc denotes coercivity along the film plane.
8. The magnetic recording medium as claimed in claim 1 , further comprising:
a Cr-M lattice matching layer having a thickness of approximately 1 nm to 15 nm formed directly on said underlayer and disposed between said underlayer and said magnetic recording layer, where M is a material selected from a group consisting of Mo, Ti, V, and W of atomic proportion greater than or equal to 5%.
9. The magnetic recording medium as claimed in claim 8 , further comprising:
an interlayer made of a slightly magnetic or nonmagnetic hcp structured CoCr alloy having a thickness of approximately 1 nm to 5 nm and disposed between said Cr-M lattice matching layer and said magnetic recording layer.
10. The magnetic recording medium as claimed in claim 1 , further comprising:
a lattice matching layer made essentially of Ru having a thickness of approximately 1 nm to 3 nm in direct contact with said magnetic recording layer and disposed between said underlayer and said magnetic recording layer.
11. A magnetic storage apparatus comprising:
at least one magnetic recording medium comprising a seed layer made of one of AlRu and AlV, a magnetic recording layer made of a CoCr alloy, and an underlayer made of the other of AlRu and AlV and disposed between the seed layer and the magnetic recording layer; and
a head which writes information on and/or reproduces information from the magnetic recording medium.
12. The magnetic storage apparatus as claimed in claim 11 , wherein said magnetic recording medium is a magnetic disk.