This application claims benefit of the Japanese Patent Application No. 2006-283018 filed on Oct. 17, 2006, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a recording thin film magnetic head, and more particularly, to a thin film magnetic head having a non-magnetic layer that is formed of a NiPRe (nickel-phosphorus-rhenium) alloy and to a method of manufacturing the thin film magnetic head.
2. Description of the Related Art
JP-A-2005-063561 discloses the composition of a NiPRe alloy having characteristics required for a gap layer. JP-A-2005-063562 discloses a thin film magnetic head having a structure in which the width of an upper magnetic layer or a lower magnetic layer in a track width direction is gradually reduced toward a gap layer interposed between the upper magnetic layer and the lower magnetic layer, as viewed from a surface opposite to a recording medium. JP-A-2004-079081 discloses a vertical magnetic recording thin film head including a main magnetic pole portion having a trapezoidal shape in which the width thereof is gradually reduced toward an auxiliary magnetic pole portion.
The NiPRe alloy having a composition ratio disclosed in JP-A-2005-063561 has a high degree of chemical resistance, and it is kept in a non-magnetic state even when it is heated at a high temperature. Therefore, the NiPRe alloy is suitably used as a material forming a gap layer of a thin film magnetic head. However, since the density of Re (rhenium) in the NiPRe alloy is high, the surface of the gap layer is rough after plating. Therefore, it is difficult to control the thickness of the gap layer, and the upper magnetic layer is not uniformly formed on the gap layer.
Since the element Re has a larger weight and a larger atomic weight than an element Ni (nickel) or P (phosphorus), the element Re is etched or milled easier or more rapidly than the element Ni or P during an etching process or a milling process. Therefore, the higher the density of Re becomes, the more rapidly the NiPRe alloy is etched or milled.
In the thin film magnetic head, the lower magnetic layer, the gap layer, and the upper magnetic layer are sequentially formed by plating, and then side milling is performed on the laminated structure to reduce a track width, thereby regulating the track width. In particular, when a gap layer is formed of the NiPRe alloy having the composition ratio disclosed in JP-A-2005-063561, the milling rate of the gap layer is considerably higher than that of the lower magnetic layer or the upper magnetic layer. Therefore, in the milling process, both side surfaces of an upper part of the lower magnetic layer formed underneath the gap layer as well as both side surfaces of the gap layer are largely grinded away, and as shown in
JP-A-2005-063562 discloses a thin film magnetic head in which the upper magnetic layer and the lower magnetic layer are formed such that the width thereof in the track width direction is gradually reduced toward the gap layer, which makes it possible to prevent the occurrence of side fringing.
When the upper magnetic layer, the gap layer, and the lower magnetic layer that are formed by plating have a large track width (in the range of 0.25 to 0.5 μm), a concave portion is formed in the gap layer, which makes it possible to prevent the side fringing.
However, in recent years, a plating technique or a resist exposing and developing technique has been developed. Therefore, it is possible to form an upper magnetic layer, a gap layer, and a lower magnetic layer having a narrow track width (in the range of 0.1 to 0.25 μm) by plating. However, as shown in
JP-A-2004-079081 discloses a vertical magnetic recording thin film head including a main magnetic pole portion having a trapezoidal shape in which the width thereof is gradually reduced toward an auxiliary magnetic pole portion, which makes it possible to prevent the occurrence of the side fringing.
In the vertical magnetic recording head, when the milling rate of a protective layer that is formed of a non-magnetic material on the main magnetic pole layer is higher than that of the main magnetic pole layer, an upper portion of the main magnetic pole layer contacting with the protective layer is also grinded away by side milling. As a result, as viewed from a surface opposite to a recording medium, concave portions are formed in both side surfaces of the main magnetic pole layer, which has a large effect on a recording track width.
Further, in JP-A-2004-079081, the main magnetic pole layer is formed by plating on a bank layer that is made of a non-magnetic material. However, since the milling rate of the bank layer is higher than the milling rate of the main magnetic pole layer, the bank layer is grinded away by side milling, and then the main magnetic pole layer is inclined, which affects the recording track width or recording characteristics.
As described above, in the vertical magnetic recording thin film head, it is preferable that the milling rate of the non-magnetic layer formed on or underneath the main magnetic pole layer be equal to the milling rate of the main magnetic pole layer.
According to an aspect of the invention, a thin film magnetic head includes: a magnetic layer; and a non-magnetic layer that is provided on or underneath the magnetic layer. In the thin film magnetic head, the non-magnetic layer is formed of a NiPRe alloy by plating. In a ternary diagram shown in
The NiPRe alloy having a composition ratio within the above-mentioned range has a high degree of chemical resistance, and thus it can be kept in a non-magnetic state even after a heat treatment is performed.
In the thin film magnetic head according to the above-mentioned aspect, preferably, the non-magnetic layer is a gap layer interposed between an upper magnetic layer and a lower magnetic layer, and at least the lower magnetic layer and the gap layer form a track width regulating portion that regulates a track width Tw in a surface opposite to a recording medium.
In the vertical magnetic recording thin film head, When the main magnetic pole layer and the non-magnetic layer formed on the main magnetic pole layer have the same milling rate, the main magnetic pole layer contacting with the non-magnetic layer is not grinded during a side milling process, and thus concave portions are not formed in both side surfaces of an upper part of the main magnetic pole layer, which does not affect a recording track width. In addition, when the main magnetic pole layer and the non-magnetic layer formed underneath the main magnetic pole layer have the same milling rate, the non-magnetic layer is not grinded during the side milling process, and the main magnetic pole is not inclined.
According to another aspect of the invention, there is provided a method of manufacturing a thin film magnetic head including a magnetic layer and a non-magnetic layer that is provided on or underneath the magnetic layer. The method includes: forming the magnetic layer by plating; plating the magnetic layer with a NiPRe alloy to form the non-magnetic layer on or underneath the magnetic layer; and milling both side surfaces of the magnetic layer in a track width direction to regulate a track width Tw. In the manufacturing method, in a ternary diagram shown in
In the method of manufacturing a thin film magnetic head according to the above-mentioned aspect, preferably, at least a lower magnetic layer and a gap layer, which is the non-magnetic layer, form a track width regulating portion. In the forming of the non-magnetic layer, preferably, the lower magnetic layer is formed by plating and then the gap layer is formed by plating. In the milling of both side surfaces of the magnetic layer, preferably, milling is performed on both side surfaces of each of the gap layer and the lower magnetic layer.
The thin film magnetic head shown in
Reference numeral 20 shown in
As shown in
As shown in
In the embodiment shown in
As shown in
A non-magnetic gap layer 22 is laminated on the lower magnetic layer 21. The gap layer 22 is formed on the lower magnetic layer 21 by plating.
Next, the upper magnetic layer 35 magnetically connected to an upper core layer 26, which will be described later, is formed on the gap layer 22 by plating. In addition, the upper magnetic layer 35 and the upper core layer 26 may be formed of the same material or different materials. The upper magnetic layer 35 is made of a magnetic material, such as a NiFe alloy, a CoFe alloy, or a CoFeNi alloy. In addition, the upper magnetic layer 35 may be composed of a single-layer film or a multi-layer film.
As shown in
As shown in
Further, an insulating layer 30 is filled up spaces among conductors of the coil layer 29. The insulating layer 30 is formed of a combination of an organic insulating material and an inorganic insulating material, such as Al2O3, and the insulating layer 30 is formed such that the inorganic insulating material is exposed to the surface opposite to the recording medium.
As shown in
As shown in
As shown in
As shown in
In the thin film magnetic head shown in
Next, characteristics of this embodiment of the invention will be described below.
In this embodiment, the gap layer 22 is formed of a NiPRe alloy by plating. The range of the composition ratio of the NiPRe alloy is defined by a ternary diagram shown in
In the ternary diagram shown in
In this embodiment of the invention, in the ternary diagram shown in
The composition ratio of the NiPRe alloy can be obtained by setting the ranges of the element P and the element Re, performing plating using the NiPRe alloy within the set composition ratio, and measuring the roughness average (Ra).
In the NiPRe alloy according to this embodiment, the element P and the element Re have a function of accelerating the amorphization of the alloy. The NiRe alloy or a NiP alloy can be easily crystallized, and the NiPRe alloy is easily crystallized by the composition ratios of the element P and the element Re. When alloy is crystallized, chemical resistance to, particularly, alkaline aqueous solution deteriorates, or the alloy is magnetized due to a heat treatment, which is undesirable.
In particular, as the content of the element P in NiPRe alloy increases, the alloy is more likely to be crystallized. Then, the chemical resistance thereof is lowered, and the alloy is easily magnetized due to a heat treatment. When the composition ratio of the element P in the NiPRe alloy is lower than 8 mass %, the alloy is not kept in a non-magnetic state during a high-temperature heat treatment. For this reason, in this embodiment, it is preferable that 8 mass % or more of the element P be contained in the NiPRe alloy.
As the content of the element P in the NiPRe alloy increases, the roughness of the plated surface tends to increase. When the content of the element P is higher than 16 mass %, the roughness average (Ra) of the plated surface is too large to control the thickness of the plated surface. Therefore, it is preferable that the content of the element P in the NiPRe alloy be equal to or lower than 16 mass %.
For the reason stated above, preferably, the content of the element P in the NiPRe alloy is within the range of about 8 mass % to about 16 mass %, that is, within the range between the straight boundary line D (including points on the boundary line D) lining points where the composition ratio of the element P is about 8 mass % and the straight boundary line E (including points on the boundary line E) linking points where the composition ratio of the element P is about 16 mass %.
Next, the composition of the element Re is examined. In the NiPRe alloy, the element P and the element Re have a function of accelerating the amorphization of the alloy, and a small amount of Re is sufficient to accelerate the non-crystalization of the alloy. Therefore, the examination proves that, when the NiPRe alloy contains 2 mass % or more of the element Re, the alloy is kept in a non-magnetic state even after a heat treatment.
The magnetic layer formed by plating needs to have a smooth surface in order to perform exact magnetic recording. However, when the surface of the gap layer surface is rough, the upper magnetic layer is not uniformly formed on the gap layer, which results in a rough upper magnetic layer. Therefore, the gap layer needs to have a smooth surface. Since the element Re has a larger atomic weight than the element Ni or the element P, the larger the content of the element Re becomes, the rougher the surface of the NiPRe alloy becomes after plating. In the NiPRe alloy, when the content of the element Re is higher than about 12 mass %, the roughness average (Ra) after plating is larger than 15 nm. As described above, when the roughness average (Ra) increases, the gap layer requiring a high degree of smoothness becomes rough, which is undesirable. Therefore, it is preferable that the content of the element Re be equal to or lower than about 12 mass %.
Further, since the element Re has a larger atomic weight and a larger weight than the element Ni or the element P, it is more likely to be grinded away by milling. The larger the content of the element Re becomes, the higher the milling rate of the NiPRe alloy becomes. The relationship between the milling rate of the NiPRe alloy, which will be described later, and the content of Re in the NiPRe alloy is examined, and the examination proves that the content of the element Re in the NiPRe alloy is preferably lower than about 12 mass %.
Therefore, it is preferable that the content of the element Re in the NiPRe alloy be in the range of about 2 mass % to about 12 mass %, that is, the composition ratio of the element Re be in the range between the straight boundary line B (including points on the boundary line B) linking points where the composition ratio of the element Re is 2 mass % and the straight boundary line C (including points on the boundary line C) linking points where the composition ratio of the element Re is 12 mass % in
When both the preferable range of the content of the element P and the preferable range of the content of the element Re are considered, in the NiPRe alloy according to this embodiment of the invention, the content of the element P is in the range of about 8 mass % to about 16 mass %, and the content of the element Re is in the range of about 2 mass % to about 12 mass %. That is, in
Furthermore, the roughness average (Ra) of the NiPRe alloy having the composition ratio within the parallelogram and in the periphery of the parallelogram after plating is examined in more detail. The roughness average (Ra) of the NiPRe alloy is measured by scanning a plated substrate with a probe at a depth of 50 nm using a contact-type thickness measuring device (Tencor P-10 (manufactured by KLA-Tencor Ltd.)).
The ternary diagram of
In the ternary diagram shown in
In the ternary diagram shown in
When the roughness average (Ra) is large, it is difficult to control the thickness of the gap layer that is formed by plating, or it is difficult to uniformly form the upper magnetic layer on the gap layer. When the gap layer is formed of the NiPRe alloy by plating, it is preferable that the roughness average (Ra) be as small as possible.
Here, a straight boundary line A (not including points on the boundary line A) linking a point a (Ni:P:Re)=(84 mass %: 16 mass %: 0 mass %) and a point b (Ni:P:Re)=(72 mass %: 0 mass %: 28 mass %) is provided between the circular plots having a roughness average (Ra) of 0.4 to 1.0 nm and the diamond-shaped plots having a roughness average (Ra) of 1.0 to 10 nm, and a composition ratio region on the left side of the boundary line A in which only the circular plots having a roughness average (Ra) 0.4 to 1.0 nm are included is used as the composition ratio range of the NiPRe alloy according to this embodiment of the invention. In the composition ratio region on the left side of the boundary line A inside the parallelogram, the contents of the element Re and the element P are small.
The composition ratio range of the NiPRe alloy according to this embodiment of the invention is surrounded by the boundary line A (not including points on the boundary line A), and the boundary lines B, C, and D (including points on the boundary lines B, C, and D), and the roughness average (Ra) after plating is in the range of 0.4 to 1.0 nm. As described above, the above-mentioned composition ratio range makes it possible to decrease the roughness average (Ra) and reduce a variation in the roughness average (Ra).
In this embodiment of the invention, the upper magnetic layer 35 can be uniformly formed on the gap layer 22 that is formed of a NiPRe alloy having a small roughness average (Ra). In addition, side milling is performed on both side surfaces of the magnetic pole portion 24 in the track width direction (the X direction in
The boundary line B shown in
Similarly, instead of defining the upper limit of the content of the element Re to 12 mass %, preferably, the boundary line C defines the upper limit of the content of the element Re to 8 mass %. That is, it is preferable that a boundary line G (
Therefore, as shown in
In
As shown in
The ends of the first and second coil pieces 37 and 38 in the track width direction are electrically connected to each other, and the first coil piece 37 and the second coil piece 38 form a solenoid-type coil layer.
In the modification shown in
Reference numeral 50 denotes a slider formed of, for example, alumina titanium carbide (Al2O3-TiC), and an Al2O3 layer 51 is formed on the slider 50.
A lower shield layer 52 formed of, for example, a NiFe-based alloy or sendust, is formed on the Al2O3 layer 51, and a gap layer 53 that is formed of, for example, Al2O3 and serves as a lower gap layer or an upper gap layer is formed on the lower shield layer 52.
A magnetoresistive element 54, which is a representative example of a GMR element, such as a spin-valve thin film element, is formed in the gap layer 53, and the front surface of the magnetoresistive element 54 is exposed toward the surface opposite to the recording medium.
An upper shield layer 57 is formed of, for example, a NiFe-based alloy on the gap layer 53.
As shown in
A protruding layer 62 that protrudes with a predetermined dimension in the height direction (the Y direction in
The protruding layer 62 and the back gap layer 63 are formed of a magnetic material, and each of the protruding layer 62 and the back gap layer 63 may be formed in a single-layer structure or a multi-layer structure.
A coil insulating base layer 64 is formed on the lower core layer 59 between the protruding layer 62 and the back gap layer 63, and a plurality of first coil pieces 65 formed of a conductive material are formed on the coil insulating base layer 64.
The first coil pieces 65 are covered with a coil insulating layer 66 that is formed of an organic insulating material or an inorganic insulating material, such as Al2O3. As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
The ends of the first and second coil pieces 65 and 76 in the track width direction are electrically connected to each other, and the first coil pieces 65 and the second coil pieces 76 form a solenoid-type coil layer 77.
A protective layer 75 made of an insulating material, such as Al2O3 or AlSiO, is formed on the coil layer 77.
In the embodiment shown in
The thin film magnetic heads shown in
Further, as shown in
In the vertical magnetic recording head, a main magnetic pole layer 90 and a non-magnetic layer 91 are sequentially formed by plating on a non-magnetic insulating layer 95 that is made of an inorganic material, such as Al2O3 or SiO2. A front surface of the main magnetic pole layer 90 is exposed to the surface opposite to the recording medium, and as shown in
As shown in
As shown in
A return yoke layer 92 is formed on the coil insulating layer 81. A front portion of the return yoke layer 92 is formed on the non-magnetic layer 91 and the insulating layer 94, and is opposite to the main magnetic pole layer 90 with the non-magnetic layer 91 interposed therebetween. In addition, a rear portion of the return yoke layer 92 is magnetically connected to the main magnetic pole layer 90. As shown in
In the vertical magnetic recording head shown in
As shown in
The vertical magnetic recording head having the above-mentioned laminated structure is covered with a protective layer 98 that is formed of, for example, an inorganic non-magnetic insulating material.
In this embodiment, as shown in
In the vertical magnetic recording head shown in
When the material forming the non-magnetic layer 91 has a high milling rate, a large amount of non-magnetic layer 91 is grinded away, and the main magnetic pole layer 90 below the non-magnetic layer 91 is also grinded away during a side milling process. As a result, concave portions are formed in both side surfaces of an upper part of the main magnetic pole layer 90, which affects the track width Tw. However, in this embodiment of the invention, the NiPRe alloy having the above-mentioned composition ratio has a low milling rate. Therefore, when the non-magnetic layer 91 is formed of the NiPRe alloy having the above-mentioned composition ratio by plating, it is possible to perform side milling on the non-magnetic layer 91 and the main magnetic pole layer 90 at the same milling rate. Therefore, it is possible to form the main magnetic pole layer 90 in a shape in which the width of the main magnetic pole layer 90 gradually increases upward, without forming concave portions in both side surfaces of the upper part of the main magnetic pole layer 90, as shown in
Further, a bank layer (not shown) formed of a non-magnetic material may be formed below the main magnetic pole layer 90. When the bank layer is formed of the NiPRe alloy having the composition ratio according to this embodiment of the invention by plating, it is possible to form a bank layer having a smooth surface since the NiPRe alloy has a small roughness average (Ra), and thus it is possible to form the main magnetic pole layer 90 on the bank layer without unevenness. In addition, the NiPRe alloy having the composition ratio according to this embodiment of the invention has a low milling rate. Therefore, when the bank layer, the main magnetic pole layer 90, and the non-magnetic layer 91 are formed by plating and side milling is performed on these layers, it is possible to prevent the bank layer from being grinded, and thus prevent the main magnetic pole layer 90 and the non-magnetic layer 91 formed on the bank layer from being inclined.
Next, a method of manufacturing the thin film magnetic head shown in
In the process shown in
Next, the Gd determining layer 27 made of, for example, a resist is formed on the seed layer 25. The Gd determining layer 27 is formed at a position that is separated from the surface opposite to the recording medium backward. For example, a heat treatment is performed on the Gd determining layer 27 to form the surface of the Gd determining layer 27 in a convex shape.
Then, a resist layer (a mask layer) 100 is formed on the Gd determining layer 27 and the entire surface of the seed layer 25, and a resist pattern 100a having a shape corresponding to the magnetic pole portion is formed on the resist layer 100 by exposure and developing processes. The resist pattern 100a is formed in a region from the surface opposite to the recording medium to the Gd determining layer 27. The width T2 of the resist pattern 100a in the track width direction (the X direction in
The maximum length L1 of the resist pattern 100a in the height direction (the Y direction in
In the next process shown in
The lower magnetic layer 21 is formed on the seed layer 25, by plating, using the seed layer 25 as an electrode. In this embodiment, the lower magnetic layer 21 is formed of a magnetic material, such as NiFe, but it may be formed of a material having higher saturation magnetic flux density (Bs) than the material forming the lower core layer 20. The lower magnetic layer 21 is formed with a thickness of about 0 to about 0.5 μm.
The gap layer 22 is formed on the lower magnetic layer 21 by plating, using the surface of the lower magnetic layer 21 as an electrode.
When the gap layer 22 is formed, in this embodiment of the invention, in the ternary diagram shown in
In this way, it is possible to set the roughness average (Ra) of the surface of the gap layer 22 within the range 0.4 to 1.0 nm, which makes it easy to form the gap layer 22 with a uniform thickness.
The gap layer 22 is formed with a thickness of about 0.05 to about 0.15 μm.
The upper magnetic layer 35 is formed on the gap layer 22 by plating, using the surface of the gap layer 22 as an electrode. However, in this case, since the surface of the gap layer 22 has a low degree of roughness and a high degree of smoothness, the upper magnetic layer 35 can be uniformly and closely formed on the gap layer 22.
The upper magnetic layer 35 is preferably formed of a magnetic material, such as NiFe, which has higher saturation magnetic flux density (Bs) than the material forming the upper core layer 26 that will be formed in a subsequent process. The upper magnetic layer 35 is formed with a thickness of about 1.5 to 3.4 μm.
Next, in the process shown in
Then, in the process shown in
In the side milling process, portions of the seed layer 25 represented by dotted lines in
As shown in
In this embodiment of the invention, the milling angle θ is set in the range of about 20 to about 60°, preferably, about 60°.
In this embodiment of the invention, when the composition ratio of the gap layer 22 is adjusted within the above-mentioned range and the milling angle θ is set in the range of about 20 to about 60°, a milling rate of both side surfaces of the gap layer 22 can be set in the range of about 4 to about 8 nm/min. Since the milling rate of both side surfaces of the lower magnetic layer 21 or the upper magnetic layer 35 is set to about 4 nm/min, the milling rate of both side surfaces of the gap layer 22 can be approximate to the milling rate of both side surface of the lower magnetic layer 21 or the upper magnetic layer 35.
In this embodiment of the invention, the milling process regulates the width of the magnetic pole portion 24 in the track width direction (the X direction in
After the milling process shown in
The vertical magnetic recording head shown in
That is, a seed layer (not shown) is formed on the insulating layer 95 by a sputtering method, and a resist layer having a resist pattern corresponding to the shapes of the main magnetic pole layer 90 and the non-magnetic layer 91 is formed on the seed layer. As viewed from the surface opposite to a recording medium, the resist pattern has a shape in which the width thereof in the track width direction gradually increases upward. The width of the surface of the resist pattern in the track width direction is slightly larger than the track width of a finished product in consideration of a chipping allowance during side milling.
Then, the main magnetic pole layer 90 and the non-magnetic layer 91 are formed in the resist pattern by plating, and the resist is removed. Alternatively, a bank layer may be formed, and then the main magnetic pole layer 90 and the non-magnetic layer 91 may be formed. Then, both side surfaces of each of the main magnetic pole layer 90 and the non-magnetic layer 91 in the vicinity of the surface opposite to the recording medium are grinded away by ion milling, thereby obtaining the main magnetic pole layer 90 and the non-magnetic layer 91 having the shapes shown in
In the thin film magnetic head shown in
In this embodiment of the invention, the following experiment is conducted, and the results of the experiment are shown in the ternary diagram of
First, the relationship between the content of an element Re in the NiPRe alloy and a milling rate after plating is examined to calculate the preferable range of the content of the element Re.
In the experiment, solid films are formed of NiPRe alloys having composition ratios a to f shown in Table 1 by plating. The milling rates thereof are measured by using an inclination angle with respect to the thickness direction of the solid film (the vertical direction of the surface of the solid film) as a milling angle θ and setting the milling angle θ to 60°. The measured results for the composition ratios are shown in Table 1. In the experiment, a resist pattern is formed on the solid film that is formed by plating, milling is performed thereon for 60 minutes using a milling machine, and the resist is removed. The height difference between a portion covered with the resist and the other portion not covered with the resist is measured by a contact-type thickness measuring device (Tencor P-10), and the height difference per unit time (minute) is calculated, thereby obtaining a milling rate (nm/min).
Further, solid films are formed of the NiPRe alloys having the composition ratios shown in Table 2 by plating, and the roughness average (Ra) of the surface of each of the solid films is measured. The measured roughness averages (Ra) and the composition ratios are shown in Table 2. As described above, the roughness average (Ra) of each of the solid films is measured by scanning a plated substrate with a probe at a depth of 50 nm using a contact-type thickness measuring device (Tencor P-10 (manufactured by KLA-Tencor Ltd.)).
The measured roughness averages (Ra) are classified into three ranges, that is, a first range of 0.4 to 1.0 nm (circular plot), a second range of 1.0 to 10 nm (diamond-shaped plot), and a third range of 10 nm or more (X plot), and the corresponding composition ratios of the NiPRe alloys are shown in the ternary diagram of
As can be seen from
Similarly,
Next, a lower magnetic layer is formed of CoFe inside the resist pattern of the resist layer, and gap layers formed of NiPRe alloys having the composition ratios according to Example 3 and Comparative example 20, respectively, are formed on the low magnetic layer. Then, an upper magnetic layer formed of CoFe is formed on the gap layer by plating, thereby obtaining a laminated structure.
Subsequently, side milling is performed on the obtained laminated structure at a milling angle θ (see
As can be seen from
On the other hand, as can be seen from
As described above, the NiPRe alloy having the composition ratio according to this embodiment of the invention makes it possible to reduce the milling rate. As a result, the milling rates of the lower magnetic layer and the upper magnetic layer are approximate to each other. Therefore, unlike the related art, it is possible to prevent large concave portions from being formed in both side surfaces of each of the gap layer and the lower magnetic layer, and thus to form the lower magnetic layer, the gap layer, and the upper magnetic layer to have substantially the same track width.
Number | Date | Country | Kind |
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2006-283018 | Oct 2006 | JP | national |