JP2007335030A - Magnetic reproducing head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic reproducing head which can suitably stabilize a magnetization direction of a free layer of a read element by being equipped with a configuration of hard film substrate in which coercive force of the hard film can be heightened more than the hard film substrate of a chrome single layer, and can maintain also the coercive force of the hard film at a part where thickness of the hard film substrate is thin. <P>SOLUTION: The magnetic reproducing head is provided with; a read element 30; an upper shield 44 and a lower shield 32 which hold the read element 30 from the upper and lower sides; a hard film 38 which is prepared between the upper shield 44 and the lower shield 32 and holds the read element 30 from both sides; and a hard film substrate 36 formed between the lower shield 32 and the hard film 38. In this case, the hard film substrate 36 consists of a chrome layer 36a and a chrome-titanium alloy layer 36b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes a read element, an upper shield and a lower shield that sandwich the read element from above and below, a hard film that sandwiches the read element from both sides, the lower shield, The present invention relates to a magnetic reproducing head including a hard film base formed between the hard film and the hard film.

  An example of the configuration of a conventional magnetic reproducing head used for reproducing (reading) a magnetic medium such as a magnetic disk is disclosed in Patent Document 1. The configuration of the magnetic reproducing head described in Patent Document 1 is shown in FIG. The conventional magnetic read head of FIG. 9 includes the soft magnetic thin film 13 as the read element (GMR element), the nonmagnetic conductive thin film 14, the magnetoresistive effect film 15, and the read element via the gap layers 122 and 121. An upper shield 112 and a lower shield 111 sandwiched from above and below, a hard film (hard magnetic thin film) 26 provided between the upper shield 112 and the lower shield 111 and sandwiching the read element from both sides, a lower shield 111 and a hard film 26, and a hard film base (base film) 252 formed therebetween.

  In Patent Document 1, a Co—Cr—Pt (cobalt / chromium / platinum alloy) -based thin film is conventionally used as the hard film, and Cr (chromium) or the like is used as the hard film base (underlayer film). It is described that a nonmagnetic film is used (Patent Document 1, paragraphs 0007, 0010, and 0011).

Japanese Patent Laying-Open No. 2005-63643 (paragraphs 0007, 0010, 0011)

Generally, since the coercive force of a hard film is affected by the properties and conditions of the hard film base, various studies have been made on the configuration of the hard film base.
Now, when chromium is used as the material for the hard film base, the coercive force of the hard film is insufficient, and it is difficult to stabilize the magnetization direction of the free layer of the read element, which causes noise and other factors. There is a problem of becoming.

  For example, when a hard film made of cobalt / chromium / platinum alloy is provided on a chromium hard film base having a thickness of about 20 to 40 mm, the coercive force Hc of the hard film is as shown in the graph of FIG. Although it is about 1300 Oe, in order to suitably stabilize the magnetization direction of the free layer of the read element, the coercive force of the hard film is preferably about 1500 Oe or more.

  In this regard, the present inventor has found that the coercive force of the hard film can be increased to about 1500 Oe or more when a chromium-titanium alloy is used as the material for the hard film base. Specifically, when a hard film made of cobalt / chromium / platinum alloy is provided on a hard film base made of chromium / titanium alloy having a thickness of about 30 to 40 mm, as can be seen from the graph of FIG. The coercive force Hc of the hard film is about 1500 Oe or more.

  As shown in FIG. 9, in the magnetic reproducing head, the thickness of the hard film base 252 is thin on the tapered portions 16 on both side surfaces of the read element. This is because when a hard film base 252 is formed, a resist layer is formed on the upper surface of the read element, and then ion beam sputtering is performed on the lower shield 111 (lower gap layer 121) and on both side surfaces of the read element. This is because the hard film base 252 is formed by the above method, and the hard film base 252 is not easily attached to both side surfaces of the read element that is formed on the side of the resist layer and is tapered.

As described above, in a magnetic read head, it is difficult to form a hard film base thick on the side surface of the read element. Therefore, it is hoped that the coercive force of the hard film can be maintained even if the hard film base is thin. It is rare.
In this regard, as can be seen from the graph of FIG. 10, the chromium hard film substrate can maintain a coercive force of about 1300 Oe up to a thickness of about 20 mm, whereas the hard film substrate made of chromium-titanium alloy has a thickness of 30 mm. If the degree is cut below, the coercive force of the hard film is lowered to 1000 Oe or less, so that the coercive force in the vicinity of the read element cannot be maintained, and there is a problem that practical use is difficult.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to increase the coercive force of the hard film as compared with the hard film base of a single chromium layer and to form the hard film even in a portion where the thickness of the hard film base is thin. It is an object of the present invention to provide a magnetic reproducing head capable of suitably stabilizing the magnetization direction of the free layer of the read element by providing a hard film base configuration capable of maintaining the coercive force of the magnetic film.

  The inventor of the present application has conducted intensive research to solve the above-mentioned problems, and as a result, the hard film base structure has a two-layer structure of a chromium layer and a chromium-titanium alloy layer, thereby forming a hard film of a single chromium layer. It has been found that the coercive force of the hard film can be increased more than that of the base, and that the coercive force of the hard film can be maintained even when the thickness of the base of the hard film is thin, and the present invention has been completed.

In order to solve the above problems, a magnetic reproducing head according to the present invention has the following configuration.
That is, a read element, an upper shield and a lower shield that sandwich the read element from above and below, a hard film that is provided between the upper shield and the lower shield, and sandwiches the read element from both sides, and the lower shield, In the magnetic reproducing head including a hard film base formed between the hard film and the hard film, the hard film base includes a chromium layer and a chromium-titanium alloy layer.

  Furthermore, the hard film is made of a cobalt / chromium / platinum alloy.

  Further, the hard film base is provided so that the lower shield side is a chromium layer and the hard film side is a chromium-titanium alloy layer.

  The hard film base is provided so that the lower shield side is a chromium-titanium alloy layer and the hard film side is a chromium layer.

  Further, the chromium-titanium alloy layer has a thickness of 18 mm or less.

  According to the magnetic read head of the present invention, the coercive force of the hard film can be increased as compared with the hard film base of a single chromium layer, and the coercive force of the hard film can be maintained even in a portion where the thickness of the hard film base is thin. By providing the configuration of the hard film base that can be used, the magnetization direction of the free layer of the read element can be preferably stabilized.

  The best mode for carrying out the magnetic reproducing head according to the present invention will be described below.

  FIG. 1 is a partial cross-sectional explanatory view showing a configuration in the vicinity of a GMR element 30 as a read element of the magnetic read head according to the first embodiment. The magnetic read head shown in FIG. 1 includes a GMR element 30 as a read element, an upper shield 44 and a lower shield 32 that sandwich the GMR element 30 from above and below via an insulating film 42 and an insulating film 34, and an upper shield 44, respectively. A hard film 38 made of cobalt / chromium / platinum alloy provided between the lower shield 32 and sandwiching the GMR element 30 from both sides, and a hard film base 36 formed between the lower shield 32 and the hard film 38. And a lead terminal 40 formed between the hard film 38 and the insulating film 42 on the upper shield 44 side.

  The magnetic read head according to the first embodiment is characterized by the configuration of the hard film base 36. The hard film base 36 has a two-layer structure in which a lower layer (lower shield side) is a chromium layer 36a made of chromium and an upper layer (hard film 38 side) is a chromium / titanium alloy layer 36b made of chromium / titanium alloy.

In manufacturing the magnetic read head, a GMR element 30 is formed on the lower shield 32 and the insulating film 34, a resist layer (not shown) is formed on the upper surface of the GMR element 30, and then the lower shield 32 (insulating) is formed. A chromium layer 36a (first layer of the hard film base 36) is formed on the film 34) and on both sides of the GMR element 30 by ion beam sputtering, and further, a chromium-titanium alloy layer 36b (hard film) is formed by ion beam sputtering. The second layer of the base 36 is formed.
Further, a hard film 38 of cobalt / chromium / platinum alloy or the like is formed on the hard film base 36 in the same manner as a known manufacturing method.

The coercive force Hc and squareness ratio of the hard film 38 when the hard film 38 of cobalt / chromium / platinum alloy is formed on the hard film base 36 having a two-layer structure of the chromium layer 36a and the chromium / titanium alloy layer 36b. The measurement results of (Mr / Ms) are shown in the graphs of FIGS.
FIG. 2 shows that the thickness of the hard film base 36, that is, the total thickness of the chromium layer 36a and the chromium-titanium alloy layer 36b is 25 mm, and the thickness X of the chromium layer 36a (that is, chromium-titanium). The thickness of the alloy layer 36b is (25Å-X)) and the relationship between the coercive force Hc of the hard film 38 (FIG. 2A) and the squareness ratio (Mr / Ms) (FIG. 2B) is measured. It is a graph which shows the result.

As shown in FIG. 10, in the case of the conventional configuration in which the hard film base is a single layer of the chromium layer, the coercive force of the hard film is about 1300 Oe, and the hard film base is a single layer of the chromium-titanium alloy layer. In this case, when the thickness is about 30 mm or less, the coercive force of the hard film is 1000 Oe or less.
On the other hand, if the hard film base 36 has a two-layer structure of the chromium layer 36a and the chromium-titanium alloy layer 36b as in the magnetic reproducing head according to the first embodiment, a hard film of 1600 Oe or more is obtained even at a thickness of 25 mm. A coercive force Hc of 38 can be obtained (when the thickness X of the chromium layer 36a is 8 to 17 mm, see FIG. 2A). The squareness ratio (Mr / Ms) indicates that an ideal value close to 1 can be obtained when the thickness of the chromium layer 36a is 11 mm or more, more preferably 15 mm or more (see FIG. 2B). ).

  FIG. 3 shows that the thickness of the hard film base 36, that is, the total thickness of the chromium layer 36a and the chromium-titanium alloy layer 36b is 20 mm, and the thickness X of the chromium layer 36a (that is, chromium-titanium). The thickness of the alloy layer 36b is (20Å-X)), and the relationship between the coercive force Hc of the hard film 38 (FIG. 3A) and the squareness ratio (Mr / Ms) (FIG. 3B) is measured. It is a graph which shows the result.

  Even in this case, when the thickness of the chromium layer 36a is about 15 mm, a preferable result with a coercive force of about 1600 Oe and a squareness ratio of about 0.9 is obtained. That is, even if the thickness of the hard film base 36 is reduced to 20 mm, an advantage is recognized as compared with a single hard film base of a chromium layer or a chromium titanium layer.

  As can be seen from FIGS. 2 and 3, in the configuration of the first embodiment in which the hard film base 36 has a two-layer structure of a chromium layer 36a and a chromium-titanium alloy layer 36b, the thickness of the chromium layer 36a is particularly 11 mm. More preferably, the thickness is 15 mm or more, and the ratio of the thickness of the chromium layer 36a in the total thickness of the hard film base 36 is 45% to 75%, more preferably 50% to 70%. Even if the hard film substrate 36 is thin, suitable coercive force characteristics and squareness characteristics can be obtained.

  Therefore, according to the magnetic reproducing head according to the first embodiment, it is possible to obtain a higher coercive force of the hard film as compared with the configuration of the conventional hard film base of the chrome layer, and at the same time, Even at the portion of the side surface where the thickness of the hard film substrate 36 is reduced, a higher coercivity of the hard film can be obtained.

  The configuration of the hard film base 36 of the magnetic reproducing head according to the first embodiment is not limited to the magnetic reproducing head including the GMR element 30 but also the magnetic reproducing including the TMR element which is a so-called read element for perpendicular magnetic recording. Of course, it can also be applied to the structure of the hard film base of the head.

  FIG. 4 is a partial cross-sectional explanatory view showing a configuration in the vicinity of the TMR element 50 of a magnetic reproducing head including the TMR element 50 as a read element for perpendicular magnetic recording and applying the configuration of the hard film base. The magnetic read head shown in FIG. 4 is provided on the TMR element 50 as a read element, the upper shield 60 and the lower shield 52 that sandwich the TMR element 50 from above and below, the lower shield 52, and the side surface of the TMR element 50. An insulating film 54, a hard film 58 made of cobalt / chromium / platinum alloy provided between the upper shield 60 and the lower shield 52 on the insulating film 54 and sandwiching the TMR element 50 from both sides, and the lower shield 52 A hard film base 56 formed between the (insulating film 54) and the hard film 58 is provided.

  The hard film base 56 has a two-layer structure in which the lower layer (lower shield side) is a chromium layer 56a made of chromium and the upper layer (hard film 38 side) is a chromium / titanium alloy layer 56b made of chromium / titanium alloy. The thickness of is set in the same manner as the magnetic reproducing head including the GMR element 30 of FIG.

  Also in the magnetic reproducing head including the TMR element 50 of FIG. 4, the provision of the hard film base 56 having the above configuration makes it possible to provide a hard film 58 having a higher height than that of the conventional single layer hard film base of the chromium layer. A coercive force can be obtained, and a coercive force of the hard film 58 higher than the conventional one can also be obtained at a portion of the side surface of the TMR element 50 where the thickness of the hard film base 56 is reduced.

Next, the configuration of the magnetic reproducing head according to the second embodiment will be described. FIG. 5 is a partial cross-sectional explanatory view showing the configuration in the vicinity of the GMR element 30 as a read element of the magnetic read head according to the second embodiment.
Note that the same reference numerals in the second embodiment denote the same parts as in the first embodiment, and a description thereof will be omitted.

  The magnetic reproducing head according to the second embodiment differs from the magnetic reproducing head according to the first embodiment in the configuration of the hard film base 62. The hard film base 62 has a two-layer structure in which a lower layer (lower shield side) is a chromium / titanium alloy layer 62a made of chromium / titanium alloy and an upper layer (hard film 38 side) is a chromium layer 62b made of chromium.

In manufacturing the magnetic read head, a GMR element 30 is formed on the lower shield 32 and the insulating film 34, a resist layer (not shown) is formed on the upper surface of the GMR element 30, and then the lower shield 32 (insulating) is formed. A chromium-titanium alloy layer 62a (first layer of the hard film base 62) is formed by ion beam sputtering on the film 34) and on both sides of the GMR element 30, and further, a chromium layer 62b (hard film) is formed by ion beam sputtering. The second layer of the base 62 is formed.
Further, a hard film 38 of cobalt / chromium / platinum alloy or the like is formed on the hard film base 62 in the same manner as in a known manufacturing method.

The coercive force Hc and squareness ratio of the hard film 38 when the hard film 38 of cobalt / chromium / platinum alloy is formed on the hard film base 62 having a two-layer structure of the chromium / titanium alloy layer 62a and the chromium layer 62b. The measurement results of (Mr / Ms) are shown in the graphs of FIGS.
FIG. 6 shows that the thickness of the hard film base 62, that is, the total thickness of the chromium / titanium alloy layer 62a and the chromium layer 62b is 25 mm, and the thickness X of the chromium / titanium alloy layer 62a (that is, The thickness of the chromium layer 62b is (25Å-X)) and the relationship between the coercive force Hc (FIG. 6A) and the squareness ratio (Mr / Ms) (FIG. 6B) of the hard film 38 is measured. It is a graph which shows the result.

  If the hard film base 62 has a two-layer structure of the chromium / titanium alloy layer 62a and the chromium layer 62b as in the magnetic reproducing head according to the second embodiment, the hard film 38 of 1400 to 1600 Oe even at a thickness of 25 mm. (When the thickness X of the chromium-titanium alloy layer 62a is 18 mm or less, see FIG. 6A). Further, it can be seen that the squareness ratio (Mr / Ms) can be obtained an ideal value close to 1 when the thickness of the chromium-titanium alloy layer 62a is 18 mm or less (see FIG. 6B).

FIG. 7 shows that the thickness of the hard film base 62, that is, the total thickness of the chromium / titanium alloy layer 62a and the chromium layer 62b is 20 mm, and the thickness X of the chromium / titanium alloy layer 62a (that is, The thickness of the chromium layer 62b is (20Å−X)), and the relationship between the coercive force Hc of the hard film 38 (FIG. 7A) and the squareness ratio (Mr / Ms) (FIG. 7B) is measured. It is a graph which shows the result.
In this case, when the thickness of the chromium-titanium alloy layer 62a is 10 mm or less, a result having a coercive force of about 1400 Oe or more and a squareness ratio of about 0.8 or more is obtained.

  As can be seen from FIGS. 6 and 7, in the configuration of the second embodiment in which the hard film base 62 has a two-layer structure of a chromium / titanium alloy layer 62a and a chromium layer 62b, the thickness of the hard film base 62 is particularly large. When the thickness is 25 mm, the thickness of the chromium-titanium alloy layer 62a is 18 mm or less, more preferably about 18 mm. Further, if the ratio of the thickness of the chromium / titanium alloy layer 62a to the total thickness of the hard film base 62 is 75% or less, even if the hard film base 62 is thin, suitable coercive force characteristics and square ratio characteristics are obtained. can get.

  According to the magnetic read head according to the second embodiment, a higher coercive force of the hard film can be obtained as compared with the conventional structure of the single layer hard film of the chromium layer, and at the same time, the side surface of the GMR element 30 can be obtained. Even in a portion where the thickness of the hard film substrate 36 is reduced, a higher coercive force of the hard film can be obtained.

  The configuration of the hard film base 62 of the magnetic reproducing head according to the second embodiment is not limited to the magnetic reproducing head including the GMR element 30, but also the magnetic reproducing including the TMR element which is a so-called read element for perpendicular magnetic recording. Of course, it can also be applied to the structure of the hard film base of the head.

FIG. 8 is a partial cross-sectional explanatory view showing a configuration in the vicinity of the TMR element 50 of a magnetic reproducing head including the TMR element 50 which is a read element for perpendicular magnetic recording and applying the configuration of the hard film base.
In the magnetic reproducing head of FIG. 8, the same components as those of the magnetic reproducing head of FIG.

  The magnetic reproducing head shown in FIG. 8 is provided on the TMR element 50 as a read element, the upper shield 60 and the lower shield 52 that sandwich the TMR element 50 from above and below, the lower shield 52, and the side surface of the TMR element 50. An insulating film 54, a hard film 58 made of cobalt / chromium / platinum alloy provided between the upper shield 60 and the lower shield 52 on the insulating film 54 and sandwiching the TMR element 50 from both sides, and the lower shield 52 A hard film base 64 formed between the (insulating film 54) and the hard film 58 is provided.

  The hard film base 64 has a two-layer structure in which a lower layer (lower shield side) is a chromium / titanium alloy layer 64a made of chromium / titanium alloy, and an upper layer (hard film 38 side) is a chromium layer 64b made of chromium. The thickness of is set in the same manner as the magnetic reproducing head including the GMR element 30 of FIG.

  Also in the magnetic reproducing head including the TMR element 50 of FIG. 8, the provision of the hard film base 64 having the above-described configuration makes it possible to provide a higher hard film 58 than that of the conventional single-layer hard film base of the chromium layer. A coercive force can be obtained, and a coercive force of the hard film 58 higher than that of the conventional hard film 58 can also be obtained at a portion of the side surface of the TMR element 50 where the thickness of the hard film base 64 is reduced.

(Appendix 1)
A read element; an upper shield and a lower shield that sandwich the read element from above and below; a hard film that is provided between the upper shield and the lower shield; and that sandwiches the read element from both sides; and the lower shield and the hard shield A magnetic reproducing head comprising a hard film substrate formed between the film and the hard film substrate, wherein the hard film substrate comprises a chromium layer and a chromium-titanium alloy layer.
(Appendix 2)
2. The magnetic reproducing head according to claim 1, wherein the hard film is made of cobalt / chromium / platinum alloy.
(Appendix 3)
3. The magnetic reproducing head according to appendix 1 or 2, wherein the hard film base is provided so that the lower shield side is a chromium layer and the hard film side is a chromium-titanium alloy layer.
(Appendix 4)
4. The magnetic read head according to appendix 3, wherein the chromium layer has a thickness of 11 mm or more.
(Appendix 5)
The magnetic reproducing head according to appendix 3 or 4, wherein a ratio of the thickness of the chromium layer to the thickness of the base of the hard film is 45% to 75%.
(Appendix 6)
3. The magnetic reproducing head according to claim 1, wherein the hard film base is provided so that the lower shield side is a chromium-titanium alloy layer and the hard film side is a chromium layer.
(Appendix 7)
The magnetic reproducing head according to appendix 6, wherein the chromium-titanium alloy layer has a thickness of 18 mm or less.
(Appendix 8)
The magnetic read head according to appendix 6 or 7, wherein the ratio of the thickness of the chromium-titanium alloy layer to the thickness of the hard film base is 75% or less.

FIG. 3 is a partial cross-sectional explanatory diagram of a magnetic reproducing head according to Example 1 of the invention. In the magnetic reproducing head according to Example 1 in which the thickness of the hard film base is set to 25 mm, the thickness of the chromium layer, the coercive force Hc (a) of the hard film, and the squareness ratio (Mr / Ms) (b) It is a graph which shows the result of having measured the relationship. In the magnetic reproducing head according to Example 1 in which the thickness of the hard film base is set to 20 mm, the thickness of the chromium layer, the coercive force Hc (a) of the hard film, and the squareness ratio (Mr / Ms) (b) It is a graph which shows the result of having measured the relationship. FIG. 6 is a partial cross-sectional explanatory diagram illustrating another configuration example of the magnetic reproducing head according to the first embodiment of the invention. FIG. 6 is a partial cross-sectional explanatory diagram of a magnetic reproducing head according to Example 2 of the invention. In the magnetic read head according to Example 2 in which the thickness of the hard film base is set to 25 mm, the thickness of the chromium layer, the coercive force Hc (a) of the hard film, and the squareness ratio (Mr / Ms) (b) It is a graph which shows the result of having measured the relationship. In the magnetic reproducing head according to Example 2 in which the thickness of the hard film base is set to 20 mm, the thickness of the chromium layer, the coercive force Hc (a) of the hard film, and the squareness ratio (Mr / Ms) (b) It is a graph which shows the result of having measured the relationship. It is a fragmentary sectional view showing another structural example of the magnetic reproducing head according to Example 2 of the invention. It is a fragmentary sectional view of a conventional magnetic reproducing head. It is a graph which shows the result of having measured the relationship between the thickness of a hard film base | substrate, and the coercive force of a hard film of the conventional magnetic read head.

Explanation of symbols

30 GMR element (read element)
32, 52 Lower shield 36, 56 Hard film base 36a, 56a Chromium layer 36b, 56b Chromium / titanium alloy layer 38, 58 Hard film 40 Lead terminal 44, 60 Upper shield 50 TMR element (lead element)
62, 64 Hard film base 62a, 64a Chromium / titanium alloy layer 62b, 64b Chromium layer

Claims (5)

A lead element;
An upper shield and a lower shield sandwiching the read element from above and below;
A hard film provided between the upper shield and the lower shield and sandwiching the read element from both side surfaces;
In a magnetic reproducing head comprising a hard film base formed between the lower shield and the hard film,
The magnetic reproducing head according to claim 1, wherein the hard film base comprises a chromium layer and a chromium-titanium alloy layer.   2. The magnetic reproducing head according to claim 1, wherein the hard film is made of cobalt / chromium / platinum alloy.   3. The magnetic reproducing head according to claim 1, wherein the hard film base is provided so that the lower shield side is a chromium layer and the hard film side is a chromium-titanium alloy layer.   3. The magnetic reproducing head according to claim 1, wherein the hard film base is provided so that the lower shield side is a chromium-titanium alloy layer and the hard film side is a chromium layer.   5. The magnetic read head according to claim 4, wherein the chromium-titanium alloy layer has a thickness of 18 mm or less.