Perpendicular magnetic recording medium and method of manufacturing the same

1. A method of manufacturing a perpendicular magnetic recording medium, the method comprising:

forming a soft magnetic layer on a substrate;

forming a first non-magnetic layer of amorphous Ni compound on the soft magnetic layer without a bias voltage applied to the substrate, the first non-magnetic layer consisting of 40 atomic % to 60 atomic % of Ni and 40 to 60 atomic % of one or more elements selected from the group consisting of Ta, Ti, Hf, Re, Os, Ir, Mo, Nb, Zr and V;

forming a second non-magnetic layer of crystalline Ni compound on the first non-magnetic layer with a bias voltage applied to the substrate, such that the first non-magnetic layer is disposed between the soft magnetic layer and the second non-magnetic layer, the second non-magnetic layer consisting of 92 to 97 atomic % of Ni and 3-8 atomic % of one or more elements selected from the group consisting of W, Cr, Mo, Re, Al, Cu and Mn;

forming an underlayer of Ru or Ru compound on the second non-magnetic layer; and

forming a magnetic recording layer above the underlayer, that records a signal.

2. A method of manufacturing a perpendicular magnetic recording medium comprising a magnetic recording layer that records a signal, an underlayer formed of Ru or Ru compound below the magnetic recording layer, a second non-magnetic layer formed of a non-magnetic crystalline material below the underlayer to control crystal orientation of the underlayer, a first non-magnetic layer formed of an amorphous material below the second non-magnetic layer, a soft magnetic layer provided below the first non-magnetic layer, and a substrate on which the magnetic recording layer, the underlayer, the first and second non-magnetic layers, and the soft magnetic layer are formed, the method comprising:

forming the soft magnetic layer by using a target of a material having a Vickers hardness of A (HV);

forming the first non-magnetic layer on the soft magnetic layer by using a target of a material having a Vickers hardness of B (HV) without a bias voltage applied to the substrate, wherein the Vickers hardness of B is larger than the Vickers hardness of A; and

forming the second non-magnetic layer on the first non-magnetic layer with a bias voltage applied to the substrate, such that the first non-magnetic layer is disposed between the soft magnetic layer and the second non-magnetic layer,

wherein the first non-magnetic layer consists of 40 atomic % to 60 atomic % of Ni and 40 to 60 atomic % of one or more elements selected from the group consisting of Ta, Ti, Hf, Re, Os, Ir, Mo, Nb, Zr and V, and

wherein the second non-magnetic layer consists of 92 to 97 atomic % of Ni and 3-8 atomic % of one or more elements elected from the group consisting of W, Cr, Mo, Re, Al, Cu and Mn.

3. The method as recited in claim 2 , wherein the second non-magnetic layer is formed of NiW.

4. The method as recited in claim 2 , wherein the first non-magnetic layer is formed of NiTa or NiTi.

5. The method as recited in claim 2 , wherein the Vickers hardness of B is not smaller than 800 HV and the Vickers hardness of A is equal to or higher than 700 HV and less than 750 HV.

6. The method as recited in claim 2 , wherein the first non-magnetic layer has a film thickness in a range of from 1 nm to 3 nm.

7. The method as recited in claim 1 , wherein the magnetic recording layer comprises a first primary recording layer and a second primary recording layer, the second primary recording layer being formed above the first primary recording layer and having a larger amount of an oxide than the first primary recording layer.

8. The method as recited in claim 2 , wherein the magnetic recording layer comprises a first primary recording layer and a second primary recording layer, the second primary recording layer being formed above the first primary recording layer and having a larger amount of an oxide than the first primary recording layer.