Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2002-05-07
2004-11-09
Bernatz, Kevin M. (Department: 1773)
Stock material or miscellaneous articles
Composite
Of inorganic material
C428S702000, C252S06251C
Reexamination Certificate
active
06815096
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
A first group of the present invention relates to a soft magnetic thin film, and a thin film magnetic head using the same. More particularly, it relates to a soft magnetic thin film having a high saturation magnetic flux density, and capable of preventing a reduction in permeability by suppressing an increase of an anisotropic magnetic field, and improving a characteristic of a thin film magnetic head.
A second group of the present invention relates to a soft magnetic thin film, and a thin film magnetic head using the same. More particularly, it relates to a soft magnetic thin film having a high saturation magnetic flux density and a small coercive force, and capable of preventing a reduction in permeability by suppressing an increase of an anisotropic magnetic field, and improving a characteristic of a thin film magnetic head.
A third group of the present invention relates to a soft magnetic thin film, and a thin film magnetic head using the same. More particularly, it relates to a soft magnetic thin film capable of setting a value of a saturation magnetic flux density and a resistance value both at high levels in a well-balanced manner, and a thin film magnetic head using the same.
2. Description of the Related Art
(1) With a higher recording density of writing on a hard disk recording medium achieved in recent years, progresses have been made in achievements of applying a magnetic head to a narrower track and a higher coercive force of the medium for writing. In a writing head of such a high recording density, in order to generate a sufficient magnetic flux, a material having a saturation magnetic flux density higher than that of permalloy conventionally used for a writing magnetic pole must be used.
An example in the related art that can meet the above-described need is a soft magnetic alloy thin film disclosed in Japanese Patent Application Laid-Open Heisei 5 (1993)-148595. This soft magnetic alloy thin film having a composition of Fe—Co—M—O (M is at least an element selected from Zr and Hf, or a mixture thereof) was developed to have a high saturation magnetic flux density, and thermal stability. According to this disclosed thin film, a high saturation magnetic flux density of about 21.0 kG at a maximum is obtained.
However, in the thin film of Fe—Co containing oxygen, an increase occurs in an anisotropic magnetic field following increased concentration of oxygen in the film, consequently causing a reduction in permeability of the film.
In order to provide a magnetic film having uniaxial magnetic anisotropy of a proper energy, high electric resistance and saturation magnetization, and a good high-frequency characteristic of permeability, Japanese Patent Application Laid-Open Heisei 5(1996)-273930 discloses an idea of adding various elements to the soft magnetic thin film of Fe—Co. Indication is made therein of a possibility of widely containing carbon and oxygen. The disclosed film contains M (at least one selected from Zr, Hf, Nb and Y) as an essential element, and preferable combinations of the elements are described to be a combination of Zr and Si, a combination of Zr and Ge, a combination of Zr and Sn, and a combination of Hf and Si. However, an actually disclosed embodiment sample is only a combination of Zr and Si, and no specific advantages of the contained carbon and oxygen is not made explicit substantially.
(2) As described above, with a higher recording density of writing on a hard disk recording medium achieved in recent years, progresses have been made in achievements of applying a magnetic head to a narrower track and a higher coercive force of the medium for writing.
In a writing head of such a high recording density, in order to generate a sufficient magnetic flux, a material having a saturation magnetic flux density higher than that of permalloy conventionally used for a writing magnetic pole must be used.
An example in the related art that can meet the above-described need is a soft magnetic alloy thin film disclosed in Japanese Patent Application Laid-Open Heisei 5 (1993)-148595. This soft magnetic alloy thin film having a composition of Fe—Co—M—O or Fe—Co—M—O—X (M is at least an element selected from the group consisting of Zr and Hf, or a mixture thereof; and X is at least an element selected from the group consisting of Y, Al, Si and B, or a mixture thereof) was developed to have a high saturation magnetic flux density, and thermal stability. According to this disclosed thin film, a high saturation magnetic flux density of about 21.0 kG at a maximum is obtained.
However, in the thin film of Fe—Co containing oxygen, an increase occurs in an anisotropic magnetic field following increased concentration of oxygen in the film, consequently causing a reduction in permeability of the film.
An example in the related art that may have a relation to the present invention is a soft magnetic alloy disclosed in Japanese Patent Application Heisei 10 (1998)-25530. This soft magnetic alloy, a specific embodiment thereof having a composition of (Co
0.72
Fe
0.28
)
59
Hf
16
O
20
C
5
, was developed to have high specific resistance and permeability in a high-frequency band as a high-frequency magnetic material. Because of a rich content of Co, however, this material has an inconvenience of a low saturation magnetic flux density compared with that of a rich content of Fe.
In order to provide a magnetic film having uniaxial magnetic anisotropy of a proper energy, high electric resistance and saturation magnetization, and a good high-frequency characteristic of permeability, Japanese Patent Application Laid-Open Heisei 8 (1996)-273930 discloses an idea of adding various elements to the soft magnetic thin film of Fe—Co. Indication is made therein of a possibility of widely containing carbon and oxygen. The disclosed film contains M (at least one selected from Zr, Hf, Nb and Y) as an essential element, and preferable combinations of the elements are described to be a combination of Zr and Si, a combination of Zr and Ge, a combination of Zr and Sn, and a combination of Hf and Si. However, an actually disclosed embodiment sample is only a combination of Zr and Si, and no specific advantages of the contained carbon and oxygen is not made explicit substantially.
(3) As described above, with a higher recording density of writing on a hard disk recording medium achieved in recent years, progresses have been made in achievements of applying a magnetic head to a narrower track and a higher coercive force of the medium for writing. In a writing head of such a high recording density, in order to generate a sufficient magnetic flux, a material having a saturation magnetic flux density higher than that of permalloy conventionally used for a writing magnetic pole must be used.
An example in the related art that can meet the above-described need is a soft magnetic alloy thin film disclosed in Japanese Patent Application Laid-Open Heisei 5 (1993)-148595. This soft magnetic alloy thin film having a composition of Fe—Co—M—O or Fe—Co—M—O—X (M is at least an element selected from the group consisting of Zr and Hf, or a mixture thereof; and X is at least an element selected from the group consisting of Y, Al, Si and B, or a mixture thereof) was developed to have a high saturation magnetic flux density, and thermal stability. According to this disclosed thin film, a high saturation magnetic flux density of about 21.0 kG at a maximum is reportedly obtained.
Considering a development of a next-generation head, however, there is no limit to requests for a higher saturation magnetic flux density of a soft magnetic thin film. On the other hand, a value of specific resistance tends to be lowered more as a saturation magnetic flux density is increased more. Therefore, a new thin film composition must be designed, which can secure a desired value of specific resistance, and simultaneously obtain a high saturation magnetic flux density. In other words, it is necessary to design a thin film composition capable of obtaining a desired value of specifi
Mino Tetsuya
Yamaguchi Atsushi
Yari Seiji
Bernatz Kevin M.
TDK Corporation
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