Thin magnetic film, method of manufacturing the same, and high frequency oscillator, magnetic head, magnetic recording medium, and magnetic recording/reproducing apparatus using thin magnetic film
View Patent ↗According to one embodiment, there is provided a thin magnetic film having a negative anisotropy of −6×10 6 erg/cm 3 or less and including, on at least a nonmagnetic substrate, at least one seed layer made of a metal or metal compound, a ruthenium underlayer for controlling the orientation of an immediately overlying layer, and a magnetic layer having negative anisotropy in the normal line direction perpendicular to a surface of the magnetic layer and mainly containing Co and Ir, wherein the additive element concentration of Ir in the magnetic layer is 10 (inclusive) to 45 (inclusive) at %.
1. A thin magnetic film comprising:
a nonmagnetic substrate;
a ruthenium underlayer formed on the nonmagnetic substrate; and
a magnetic layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −6×10 6 to −1.2×10 7 erg/cm 3 (−6×10 8 to −1.2×10 9 nJ/cm 3 ) in a normal line direction perpendicular to a surface of the magnetic layer, and mainly containing Co 1-x Ir x (x=10 to 45 at %).
2. The film according to claim 1 , wherein the ruthenium underlayer is annealed at a temperature of 400° C. (inclusive) to 650° C. (exclusive).
3. The film according to claim 1 , further comprising, between the nonmagnetic substrate and the ruthenium underlayer, a seed layer made of at least one material selected from the group consisting of tantalum, platinum, titanium, and nickel.
4. A thin magnetic film manufacturing method comprising:
forming a ruthenium underlayer on a nonmagnetic substrate;
annealing the ruthenium underlayer at a temperature of 400° C. (inclusive) to 650° C. (exclusive); and
forming a magnetic layer mainly containing Co 1-x Ir x (x=10 to 45 at %), in contact with the annealed ruthenium underlayer.
5. The method according to claim 4 , further comprising, before the forming the ruthenium underlayer on the nonmagnetic substrate, forming a seed layer made of at least one material selected from the group consisting of tantalum, platinum, titanium, and nickel.
6. A high frequency oscillator comprising:
a first electrode;
a ruthenium underlayer formed on the first electrode;
a first magnetic layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −6×10 6 to −1.2×10 7 erg/cm 3 (−6×10 8 to −1.2×10 9 nJ/cm 3 ) in a normal line direction perpendicular to a surface of the first magnetic layer, and mainly containing Co 1-x Ir x (x=10 to 45 at %);
a nonmagnetic interlayer formed on the first magnetic layer;
a second magnetic layer formed on the nonmagnetic interlayer, having perpendicular magnetic anisotropy, and containing at least one magnetic material selected from the group consisting of iron, cobalt, and nickel; and
a second electrode formed on the second magnetic layer.
7. The oscillator according to claim 6 , wherein the ruthenium underlayer is annealed at a temperature of 400° C. (inclusive) to 650° C. (exclusive).
8. The oscillator according to claim 6 , further comprising, between the nonmagnetic substrate and the ruthenium underlayer, a seed layer made of at least one material selected from the group consisting of tantalum, platinum, titanium, and nickel.
9. A magnetic head comprising:
a main magnetic pole;
a recording magnetic pole forming a magnetic circuit together with the main magnetic pole; and
a high frequency oscillator formed between the main magnetic pole and the recording magnetic pole and comprising
a first electrode,
a ruthenium underlayer formed on the first electrode,
a first magnetic layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −6×10 6 to −1.2×10 7 erg/cm 3 (−6×10 8 to −1.2×10 9 nJ/cm 3 ) in a normal line direction perpendicular to a surface of the first magnetic layer, and mainly containing Co 1-x Ir x (x=10 to 45 at %),
a nonmagnetic interlayer formed on the first magnetic layer,
a second magnetic layer formed on the nonmagnetic interlayer, having perpendicular magnetic anisotropy, and containing at least one magnetic material selected from the group consisting of iron, cobalt, and nickel, and
a second electrode formed on the second magnetic layer.
10. A magnetic recording/reproducing apparatus including a magnetic head comprising:
a main magnetic pole;
a recording magnetic pole forming a magnetic circuit together with the main magnetic pole; and
a high frequency oscillator formed between the main magnetic pole and the recording magnetic pole and comprising
a first electrode,
a ruthenium underlayer formed on the first electrode,
a first magnetic layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −6×10 6 to −1.2×10 7 erg/cm 3 (−6×10 8 to −1.2×10 9 nJ/cm 3 ) in a normal line direction perpendicular to a surface of the first magnetic layer, and mainly containing Co 1-x Ir x (x=10 to 45 at %),
a nonmagnetic interlayer formed on the first magnetic layer,
a second magnetic layer formed on the nonmagnetic interlayer, having perpendicular magnetic anisotropy, and containing at least one type of a magnetic material selected from the group consisting of iron, cobalt, and nickel, and
a second electrode formed on the second magnetic layer.
11. A perpendicular magnetic recording medium comprising:
a nonmagnetic substrate;
a ruthenium underlayer formed on the nonmagnetic substrate;
a soft magnetic backing layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −6×10 6 to −1.2×10 7 erg/cm 3 (−6×10 8 to −1.2×10 9 nJ/cm 3 ) in a normal line direction perpendicular to a surface of the soft magnetic backing layer and mainly containing Co 1-x Ir x (x=10 to 45 at %); and
a perpendicular magnetic recording layer formed on the soft magnetic backing layer and containing cobalt, chromium, and platinum.
12. The medium according to claim 11 , wherein the ruthenium underlayer is annealed at a temperature of 400° C. (inclusive) to 650° C. (exclusive).
13. The medium according to claim 11 , further comprising, between the nonmagnetic substrate and the ruthenium underlayer, a seed layer made of at least one type of a material selected from the group consisting of tantalum, platinum, titanium, and nickel.
14. A magnetic recording/reproducing apparatus comprising:
a perpendicular magnetic recording medium comprising
a nonmagnetic substrate,
a ruthenium underlayer formed on the nonmagnetic substrate,
a soft magnetic backing layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −6×10 6 to −1.2×10 7 erg/cm 3 (−6×10 8 to −1.2×10 9 nJ/cm 3 ) in a normal line direction perpendicular to a surface of the soft magnetic backing layer, and mainly containing Co 1-x Ir x (x=10 to 45 at %), and
a perpendicular magnetic recording layer formed on the soft magnetic backing layer and containing cobalt, chromium, and platinum; and
a magnetic head.