Multilayer film, magnetic head, magnetic head device, magnetic recording/reproducing apparatus and method for manufacturing multilayer film

1. A multilayer film comprising:

a magnetic film; and

a non-magnetic film,

the magnetic film and the non-magnetic film being alternately stacked, the magnetic film containing Fe, Ni and P but having Fe or Ni as a main component, the non-magnetic film containing Fe, Ni and P but having Ni as a main component.

2. The multilayer film of claim 1 , wherein the magnetic film contains from 60 to 90 at. % Fe, from 5 to 30 at. % Ni and from 5 to 20 at. % P, while the non-magnetic film contains from 5 to 20 at. % Fe, from 65 to 85 at. % Ni and from 10 to 30 at. % P.

3. A method for manufacturing a multilayer film, the multilayer film including a magnetic film and a non-magnetic film, the magnetic film and the non-magnetic film being alternately stacked, the magnetic film containing Fe, Ni and P but having Fe or Ni as a main component, the non-magnetic film containing Fe, Ni and P but having Ni as a main component, the method comprising a process of depositing the magnetic film and the non-magnetic film by changing a composition ratio of the Fe, Ni and P.

4. The multilayer film manufacturing method of claim 3 , including a process of alternately depositing the magnetic film and the non-magnetic film as a plating film in a plating bath with a pulse current,

wherein the pulse current is divided into a plurality of sections and, in each of the sections, serves as a pulse current having a frequency f with one cycle composed of a period T 1 during which a current I 1 flows and a period T 2 during which a current I 2 flows in a direction opposite to the current I 1 , and

the current I 1 , the current I 2 , the period T 1 , the period T 2 and the frequency f are set to deposit either the magnetic film or the non-magnetic film in each of the sections.

5. The multilayer film manufacturing method of claim 4 , wherein the current I 1 , the current I 2 , the period T 1 and the period T 2 satisfy a relationship of

5 (mA/cm 2 )≦ I 1≦30 (mA/cm 2 ),

−10 (mA/cm 2 )≦ I 2≦0 (mA/cm 2 ), and

0.2 ≦T 1/( T 1 +T 2)≦0.8.

6. The multilayer film manufacturing method of claim 4 , wherein the plating bath includes Ni ion, Fe ion, a stress releaser and a surfactant, the Ni ion has an ionic valence of 2 and a concentration of from 2 to 50 g/L, and the Fe ion has an ionic valence of 2 and a concentration of from 1 to 10 g/L.

7. The multilayer film manufacturing method of claim 4 , wherein the plating bath includes FeSO 4 .7H 2 O, NiSO 4 .6H 2 O, NH 4 C1, H 3 BO 3 , (C 7 H 5 NO 3 S)Na and NaPH 2 O 2 .H 2 O, and the current I 1 , the current I 2 , the period T 1 , the period T 2 and the frequency f satisfy a relationship of

I 2 =−I 1×0.35,

T 1/( T 1 +T 2)=0.625, and

f= 25 Hz.

8. A magnetic head comprising:

a magnetic shield, the magnetic shield being a multilayer film, the multilayer film including

a magnetic film, and

a non-magnetic film,

the magnetic film and the non-magnetic film being alternately stacked, the magnetic film containing Fe, Ni and P but having Fe or Ni as a main component, the non-magnetic film containing Fe, Ni and P but having Ni as a main component.

9. A magnetic head device comprising:

a magnetic heat; and

a head support device,

the magnetic head being the magnetic head of claim 8 , the head support device supporting the magnetic head.

10. A magnetic recording/reproducing apparatus comprising:

a magnetic head device; and

a magnetic recording medium,

the magnetic head device being the magnetic head device of claim 9 and configured to perform magnetic recording and reproducing of magnetic record with the magnetic recording medium.

11. A method for manufacturing a magnetic head including a magnetic shield, the magnetic shield being a multilayer film, the multilayer film including a magnetic film and a non-magnetic film, the magnetic film and the non-magnetic film being alternately stacked, the magnetic film containing Fe, Ni and P but having Fe or Ni as a main component, the non-magnetic film containing Fe, Ni and P but having Ni as a main component, the method comprising a process of depositing the magnetic film and the non-magnetic film by changing a composition ratio of the Fe, Ni and P.

12. The method for manufacturing a magnetic head including a magnetic shield of claim 11 , including a process of alternately depositing the magnetic film and the non-magnetic film as a plating film in a plating bath with a pulse current,

wherein the pulse current is divided into a plurality of sections and in each of the sections, serves as a pulse current having a frequency f with one cycle composed of a period T 1 during which a current I 1 flows and a period T 2 during which a current I 2 flows in a direction opposite to the current I 1 , and

the current I 1 , the current I 2 , the period T 1 , the period T 2 and the frequency f are set to deposit either the magnetic film or the non-magnetic film in each of the sections.

13. The method for manufacturing a magnetic head including a magnetic shield of claim 12 , wherein the current I 1 the current I 2 , the period T 1 and the period T 2 satisfy a relationship of

5 (mA/cm 2 )≦ I 1≦30 (mA/cm 2 ),

−10 (mA/cm 2 )≦ I 2≦0 (mA/cm 2 ), and

0.2 ≦T 1/( T 1 +T 2)≦0.8.

14. The method for manufacturing a magnetic head including a magnetic shield of claim 12 , wherein the plating bath includes Ni ion, Fe ion, a stress releaser and a surfactant, the Ni ion has an ionic valence of 2 and a concentration of from 2 to 50 g/L, and the Fe ion has an ionic valence of 2 and a concentration of from 1 to 10 g/L.

15. The method for manufacturing a magnetic head including a magnetic shield of claim 12 , wherein the plating bath includes FeSO 4 .7H 2 O, NiSO 4 .6H 2 O, NH 4 C1, H 3 BO 3 , (C 7 H 5 NO 3 S)Na and NaPH 2 O 2 .H 2 O, and the current I 1 , the current I 2 , the period T 1 , the period T 2 and the frequency f satisfy a relationship of

I 2 =−I 1×0.35,

T 1/( T 1 +T 2)=0.625, and

f= 25 Hz.