High saturtion magnetization material and magnetic head fabricated therefrom

• US 5,763,108 A
• Filed: 03/05/1997
• Issued: 06/09/1998
• Est. Priority Date: 03/05/1997
• Status: Expired due to Fees

• Current Assignee: Headway Technologies Incorporated (TDK Corporation)
• Original Assignee: Headway Technologies Incorporated (TDK Corporation)
• Inventors: Yasuda, Kazumasa, Lau, Wen-Cherng, Chang, Jei-Wei
• Primary Examiner(s): KILIMAN, LESZEK B
• Application Number:
  US08/810,061
• Time in Patent Office: 461 Days
• Field of Search: 428/694 R, 428/694 TR, 428/694 TS, 428/900, 360/113, 324/252, 205/90
• US Class Current: 428/812
• CPC Class Codes: G11B 5/3109 Details G11B5/3103 takes precedence
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• CPC Class Codes: G11B 5/3967 Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read G11B5/3906 takes precedence
• CPC Class Codes: H01F 10/14 containing iron or nickel H01F10/126 , H01F10/13, H01F10/16 take precedence
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/115 Magnetic layer composition

Abstract

A magnetic material which may be employed as a thin film magnetic layer within magnetic heads, and a method for forming the magnetic material as a thin film magnetic layer for use within magnetic heads. The magnetic material has an elemental composition comprising about 40 to about 60 weight percent iron, about 40 to about 60 weight percent nickel and about 0.002 to about 1 weight percent tin. The magnetic material may be formed as a thin film magnetic layer for use within a magnetic head through an electrochemical plating method employing an aqueous plating solution comprising iron (II) ions, nickel (II) ions and tin (II) ions. When electrodeposited and anisotropically magnetically aligned, or when thermally annealed and anisotropically magnetically aligned the thin film magnetic layer possess a higher saturation magnetization, a higher anisotropy, a comparable easy axis coercivity, a lower hard axis permittivity and a higher resistivity than conventional thin film magnetic layers formed of permalloy (nickel-iron 80:20 w/w) alloys.

Claims

1. A magnetic material having an elemental composition comprising:

about 40 to about 60 weight percent iron;

about 40 to about 60 weight percent nickel; and

about 0.002 to about 1 weight percent tin.

2. A magnetic thin film having an elemental composition comprising:

about 40 to about 60 weight percent iron;

about 40 to about 60 weight percent nickel; and

about 0.002 to about 1 weight percent tin.

3. The magnetic thin film of claim 2 wherein:

the magnetic thin film has a thickness of from about 1 to about 4 microns;

the magnetic thin film is anisotropically magnetically aligned to form an anisotropically magnetically aligned magnetic thin film having;

a saturation magnetization of from about 12 to about 16 kgauss;

a magnetic anisotropy of from about 8 to about 16 oersteds;

an easy axis coercivity of from about 0.3 to about 1.0 oersteds;

a hard axis permittivity of from about 1000 to about 4000 gauss; and

a resistivity of from about 25 to about 70 micro-ohm.cm.

4. The magnetic thin film of claim 2 wherein the magnetic thin film is formed through a deposition method selected from the group of deposition methods consisting of plating deposition methods, evaporation deposition methods and sputtering deposition methods.

5. A magnetic head having formed therein the anisotropically magnetically aligned magnetic thin film of claim 3, wherein:

the magnetic head is chosen from the group of magnetic heads consisting of inductive read magnetic heads, inductive write magnetic heads, inductive read-write magnetic heads and magnetoresistive (MR) read-write magnetic heads; and

the anisotropically magnetically aligned magnetic thin film is employed within the magnetic head as a layer selected from the group of layers consisting of magnetic read inductor layers, magnetic write inductor layers, magnetic read-write inductor layers and magnetic shield layers.

6. A magnetic sensor having fabricated therein the anisotropically magnetically aligned magnetic thin film of claim 3, wherein the anisotropically magnetically aligned magnetic thin film is employed as a magnetic magnetic flux guide within the magnetic sensor.

7. A method for forming a magnetic thin film comprising:

providing a substrate; and

forming through an electroplating method over the substrate a magnetic thin film, the magnetic thin film having an elemental composition comprising;

about 40 to about 60 weight percent iron;

about 40 to about 60 weight percent nickel; and

about 0.02 to about 1 weight percent tin.

8. The method of claim 7 wherein the electroplating method employs an aqueous electroplating solution comprising:

about 0.4 to about 0.9 moles per liter iron (II) ions;

about 0.2 to about 0.8 moles per liter nickel (II) ions; and

about 0.002 to about 0.010 moles per liter tin (II) ion.

9. The method of claim 8 wherein the electroplating method also employs:

a pH of from about 2.0 to about 3.5;

a temperature of from about 20 to about 35 degrees centigrade;

a current density of from about 5 to about 20 milli-amps per square centimeter; and

a plating voltage of from about 0.5 to about 5 volts.

10. The method of claim 7 wherein the magnetic thin film is formed to a thickness of from about 1 to about 4 microns.

11. The method of claim 7 further comprising anisotropically magnetically aligning the magnetic thin film in a magnetic field of from about 100 to about 3000 gauss to form over the substrate an anisotropically magnetically aligned magnetic thin film having:

a saturation magnetization of from about 12 to about 16 kgauss;

an anisotropy of from about 8 to about 16 oersteds;

an easy axis coercivity of from about 0.3 to about 1.0 oersteds;

a hard axis permittivity of from about 1000 to about 4000; and

a resistivity of from about 25 to about 70 micro-ohm.cm.

12. The method of claim 11 wherein the magnetic thin film is anisotropically magnetically aligned while the magnetic thin film is formed over the substrate through the electrochemical plating method.

13. The method of claim 11 wherein the magnetic thin film is anisotropically magnetically aligned after the magnetic thin film is formed over the substrate through the electrochemical plating method.

14. The method of claim 7 further comprising annealing the magnetic thin film at a temperature of from about 120 to about 300 degrees centigrade while simultaneously anisotropically magnetically aligning the magnetic thin film within a magnetic field of from about 100 to about 3000 gauss to form from the magnetic thin film a thermally annealed and anisotropically magnetically aligned magnetic thin film having:

a saturation magnetization of from about 12 to about 16 kgauss;

an anisotropy of from about 8 to about 16 oersteds;

an easy axis coercivity of from about 0.3 to about 1.0 oersteds;

a hard axis permittivity of from about 1000 to about 4000; and

a resistivity of from about 25 to about 70 micro-ohm.cm.

15. A magnetic head having formed therein the anisotropically magnetically aligned magnetic thin film of claim 11, wherein:

the magnetic head is chosen from the group of magnetic heads consisting of inductive read magnetic heads inductive write magnetic heads, inductive read-write magnetic heads and magnetoresistive (MR) read-write magnetic heads; and

the anisotropically magnetically aligned magnetic thin film is employed within the magnetic head as a layer selected from the group of layers consisting of magnetic read inductor layers, magnetic write inductor layers, magnetic read-write inductor layers and magnetic shield layers.

16. A magnetic sensor having fabricated therein the anisotropically magnetically aligned magnetic thin film of claim 11, wherein the anisotropically magnetically aligned magnetic thin film is employed as a magnetic flux guide within the magnetic sensor.

17. A magnetic head having formed therein the thermally annealed and anisotropically magnetically aligned magnetic thin film of claim 14, wherein:

the magnetic head is chosen from the group of magnetic heads consisting of inductive read magnetic heads, inductive write magnetic heads, inductive read-write magnetic heads and magnetoresistive (MR) read-write magnetic heads; and

the thermally annealed and anisotropically magnetically aligned magnetic thin film is employed within the magnetic head as a layer selected from the group of layers consisting of magnetic read inductor layers, magnetic write inductor layers, magnetic read-write inductor layers and magnetic shield layers.

18. A magnetic sensor having fabricated therein the thermally annealed and anisotropically magnetically aligned magnetic thin film of claim 14, wherein the thermally annealed and anisotropically magnetically aligned magnetic thin film is employed as a magnetic flux guide within the magnetic sensor.