JP2005235387A - Magnetoresistive effect head and magnetic recording reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain hard magnetic characteristics, and an appropriate head characteristics by reducing head noise, and prevent a recording reproducing characteristics deterioration by preventing undulation in a write head in a magnetoresistive effect head and a magnetic recording reproducing device. <P>SOLUTION: A magnetoresistive effect film of the magnetoresistive effect element includes a stabilization bias layer for impressing a magnetization stabilization bias magnetic field and the ferromagnetic material comprising a foundation layer for the stabilization bias layer. The ferromagnetic material is configured to consist of Fe alloy, FeCo alloy, FeCoNi alloy or FeNi alloy to which at least one element chosen from a group consisting of Pt, Pd, Ir, Rh, Ru, Au is added. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetoresistive head and a magnetic recording / reproducing apparatus, and more particularly, to a magnetoresistive head using a stabilizing bias layer that applies a magnetization stabilizing bias magnetic field to the magnetoresistive film and such a magnetoresistive effect type. The present invention relates to a magnetic recording / reproducing apparatus including a head.

FIG. 1 is a cross-sectional view showing a main part of a conventional magnetoresistive head. As shown in the figure, in the conventional magnetoresistive head, a rectangular magnetoresistive element 1 is connected to an element terminal 3, and the upper and lower sides of the magnetoresistive element (spin valve element) 1 and the element terminal 3 are alumina ( Insulated by Al ₂ O ₃ ) layers 4 and 5. The upper and lower sides of these alumina layers 4 and 5 are shielded by two soft magnetic bodies (NiFe) (not shown).

  The reproducing element includes a longitudinal bias application layer 7 for stabilizing the reproduction output, and a hard magnetic material is used for the longitudinal bias application layer 7. It is known that the hard magnetic characteristics can be improved by using a thin film having a bcc crystal structure as the base of the hard magnetic material.

For example, Patent Document 1 proposes to improve the stability of reproduction output by using a thin film having a bcc crystal structure as a base of a hard magnetic material. Improvement of reproduction output stabilization in this case is considered because a ferromagnetic material such as Fe exchange-couples with the free layer of the spin valve element. For example, when a hard magnetic material made of CoCrPt is used as a base of 10 nm Fe or 10 nm FeCr, the magnetic field becomes 1000 to 1200 Oe, and Barkhausen noise can be effectively suppressed.
JP-A-9-97409

  CoCrPt used as a hard magnetic material has a high specific resistance of 60 to 80 μΩcm. Therefore, the resistance value of the magnetoresistive head as a whole is increased, causing head noise (white noise), and there is a problem that head characteristics are deteriorated.

CoC used as a hard magnetic material
The residual magnetization of rPt is low, and it was necessary to increase the film thickness in order to obtain sufficient head characteristics. However, when the thickness of the hard magnetic material is increased, there is a problem that waviness occurs in the write head and the recording / reproducing characteristics are deteriorated.

  Further, when CoPt having a high magnetic flux density is used as a hard magnetic material and a ferromagnetic underlayer film having a bcc crystal structure proposed in tokkyo Japanese Patent Laid-Open No. Hei 1 is used, as shown in FIG. There was also a problem that it was difficult to obtain hard magnetic properties. The figure shows the characteristics of a ferromagnetic underlayer having a bcc crystal structure when the Fe layer is 3 nm and the CoPt layer is 10 nm. The vertical axis indicates magnetization (Gauss) and the horizontal axis indicates magnetic field (Oe). .

  Therefore, in view of the above problems, the present invention can reduce head noise and obtain good head characteristics, prevent waviness of the write head and prevent deterioration of recording and reproduction characteristics, and good hard magnetic properties. It is an object of the present invention to provide a magnetoresistive head and a magnetic recording / reproducing apparatus capable of obtaining characteristics.

  The above-described problem includes a stabilizing bias layer that applies a magnetization stabilizing bias magnetic field to a magnetoresistive effect film of a magnetoresistive effect element, and a ferromagnetic material that forms an underlayer of the stabilizing bias layer, The body is made of Fe and can be achieved by a magnetoresistive head having a film thickness of 1.3 to 2.5 nm. According to the magnetoresistive head according to the present invention, it is possible to reduce head noise and obtain good head characteristics, to prevent waviness of the write head and to prevent deterioration of recording and reproduction characteristics, and to obtain good hardness. Magnetic characteristics can be obtained.

  In this case, the stabilizing bias layer may be made of a Co-based alloy or a CoPt alloy.

  The above-described problem includes a stabilizing bias layer that applies a magnetization stabilizing bias magnetic field to a magnetoresistive effect film of a magnetoresistive effect element, and a ferromagnetic material that forms an underlayer of the stabilizing bias layer, The body is made of an Fe alloy to which at least one element selected from the group consisting of Co, Ni, Cr, Nb, Mo, Ta, V, and W is added, and has a thickness of 2.5 to 4.9 nm. This can also be achieved by a magnetoresistive head. According to the magnetoresistive head according to the present invention, it is possible to reduce head noise and obtain good head characteristics, to prevent waviness of the write head and to prevent deterioration of recording and reproduction characteristics, and to obtain good hardness. Magnetic characteristics can be obtained.

  In this case, the ferromagnetic material may be composed of an FeCr alloy having a Cr composition of 10 to 20 at%.

  The above-described problem includes a stabilizing bias layer that applies a magnetization stabilizing bias magnetic field to a magnetoresistive effect film of a magnetoresistive effect element, and a ferromagnetic material that forms an underlayer of the stabilizing bias layer, The body can also be achieved by a magnetoresistive head made of an Fe alloy to which at least one element selected from the group consisting of Pt, Pd, Ir, Rh, Ru, and Au is added. According to the magnetoresistive head according to the present invention, it is possible to reduce head noise and obtain good head characteristics, to prevent waviness of the write head and to prevent deterioration of recording and reproduction characteristics, and to obtain good hardness. Magnetic characteristics can be obtained.

  In this case, the ferromagnetic material may be composed of an FePt alloy having a Pt composition of 1 to 25 at%. The ferromagnetic material may have a thickness of 2.5 nm or more. Furthermore, the stabilizing bias layer may be made of a CoPt alloy. The above-described problem includes a stabilizing bias layer that applies a magnetization stabilizing bias magnetic field to a magnetoresistive effect film of a magnetoresistive effect element, and a ferromagnetic material that forms an underlayer of the stabilizing bias layer, The body can also be achieved by a magnetoresistive head made of FeCo alloy, FeCoNi alloy or FeNi alloy to which at least one element selected from the group consisting of Pt, Pd, Ir, Rh, Ru and Au is added.

  The above problem can also be achieved by a magnetic recording / reproducing apparatus including the magnetoresistive head having the above-described configuration. According to the magnetic recording / reproducing apparatus of the present invention, the head noise can be reduced to obtain good head characteristics, the write head can be prevented from wobbling to prevent the recording / reproducing characteristics from being deteriorated, and good hard magnetism can be obtained. Characteristics can be obtained.

  According to the present invention, it is possible to obtain good head characteristics by reducing head noise, to prevent waviness of the write head, to prevent deterioration of recording and reproducing characteristics, and to obtain good hard magnetic characteristics. A magnetoresistive head and a magnetic recording / reproducing apparatus can be realized.

  The embodiment of the present invention will be described below with reference to FIG.

  First, a first embodiment of the magnetoresistive head according to the present invention will be described. FIG. 3 is a cross-sectional view for explaining the manufacturing process of the first embodiment of the magnetoresistive head. FIG. 4 is a cross-sectional view showing the main part of the first embodiment of the magnetoresistive head.

In FIG. 3, the lower shield layer 10 made of FeZrN is formed with a film thickness of, for example, 2 μm on a substrate (not shown) by sputtering. On the magnetic shield layer 10, a lower gap layer 11 made of alumina (Al ₂ O ₃ ) is formed with a film thickness of 50 nm, for example. A magnetoresistive effect element (spin valve element) 12 is formed on the lower gap layer 11. This magnetoresistive element 12 has Ta (5) / NiFe (2) / CoFeB (1.5) / Cu (3) / CoFeB (2) / PdPtMn (), where the value in parentheses indicates the film thickness in nm. 20) / Ta (6) nm. Needless to say, the magnetoresistive effect element 12 is not limited to a spin valve element, and may be a magnetoresistive effect element such as AMR or TMR.

  Next, a resist film 13 having a width of 1 μm and a height of 3 μm, for example, is formed on the magnetoresistive effect element 12 by patterning, and the resist film 13 is used as a mask to dry-etch the magnetoresistive effect element 12 to form the lower gap layer. Etch until 11 is exposed. In this state, as shown in FIG. 4, a ferromagnetic underlayer 15 made of, for example, 1.6 nm of Fe and a hard magnetic layer 16 made of, for example, 30 nm of CoPt are sequentially formed on the exposed lower gap layer 11. The hard magnetic layer 16 constitutes a stabilizing bias layer for applying a magnetization stabilizing bias magnetic field to the magnetoresistive effect film of the magnetoresistive effect element 12. The film thickness of the hard magnetic layer 16 is desirably set so as to have a residual magnetization of about 1 to 7 times the magnetization of the free layer of the magnetoresistive element 12.

  Thereafter, an element terminal 17 made of, for example, 80 nm Ta is formed on the hard magnetic layer 16, and after the resist layer 13 is removed, an upper gap layer 18 made of, for example, 50 nm of alumina and an upper shield made of, for example, 2 μm of FeZrN. Layer 19 and the like are formed. Since the other manufacturing processes of the magnetoresistive head can use known processes, illustration and description thereof are omitted in this specification.

  The hard magnetic layer 16 may be composed of CoPt or a Co-based alloy. The magnetization of the Fe ferromagnetic underlayer 15 is, for example, 22 kGauss, and the magnetization of the CoPt hard magnetic layer 16 is, for example, 14 kGauss.

  Next, a description will be given of a second embodiment of the magnetoresistive head according to the present invention. In the present embodiment, the basic configuration of the magnetoresistive head is the same as that of the first embodiment, and the illustration thereof is omitted. This embodiment is different from the first embodiment in that the ferromagnetic underlayer 15 is made of FeCr instead of Fe and the film thickness of the ferromagnetic underlayer 15 is set to 4 nm, for example.

  FIG. 5 is a diagram showing the magnetic characteristics of the CoPt hard magnetic layer 16 in the first and second embodiments. In the figure, the vertical axis represents the magnetic field Hc (Oe), and the horizontal axis represents the film thickness (nm) of the ferromagnetic underlayer 15. In the figure, characteristic I shows the case where the ferromagnetic underlayer 15 is made of Fe in the first embodiment, and characteristic II shows the case where the ferromagnetic underlayer 15 is made of FeCr in the second embodiment. The thickness of the magnetic layer 18 is assumed to be 10 nm. From the characteristic I, it can be seen that the optimum value of the film thickness of the Fe ferromagnetic underlayer 15 in the first example is 1.3 to 2.5 nm. It can also be seen that the optimum value of the film thickness of the FeCr ferromagnetic underlayer 15 in the second example is 2.5 nm or more.

  As described above, according to the first and second embodiments, the magnetic characteristics of the hard magnetic layer 16 can be improved by using the Fe or FeCr ferromagnetic underlayer 15 having an optimum film thickness. In addition, when FeCr is used for the ferromagnetic underlayer 15, the range of the optimum film thickness can be further expanded as compared with the case where Fe is used. Further, by using CoPt for the hard magnetic layer 16, the film thickness can be reduced as compared with the case of using CoCrPt, thereby causing no waviness in the write head and stable with less noise. A magnetoresistive head can be realized. Also, the yield of the magnetoresistive head can be improved.

  Next, a description will be given of a third embodiment of the magnetoresistive head according to the present invention. In the present embodiment, the basic configuration of the magnetoresistive head is the same as that of the first embodiment, and the illustration thereof is omitted. In this embodiment, the ferromagnetic underlayer 15 is made of an Fe alloy to which at least one element selected from the group consisting of Co, Ni, Cr, Nb, Mo, Ta, V, and W is added instead of Fe. This is different from the first embodiment in that the ferromagnetic underlayer 15 is configured to have a thickness of 2.5 to 4.9 nm.

  When the ferromagnetic underlayer 15 is made of an FeCr alloy, the Cr composition is preferably 10 to 20 at%.

  Next, a description will be given of a fourth embodiment of the magnetoresistive head according to the present invention. In the present embodiment, the basic configuration of the magnetoresistive head is the same as that of the first embodiment, and the illustration thereof is omitted. In this embodiment, the ferromagnetic underlayer 15 is made of an Fe alloy to which at least one element selected from the group consisting of Pt, Pd, Ir, Rh, Ru, and Au is added instead of Fe. The difference from the first embodiment is that the thickness of the magnetic underlayer 15 is set to 2.5 nm or more.

  When the ferromagnetic underlayer 15 is made of an FePt alloy, the Pt composition is preferably 1 to 25 at%.

  FIG. 6 is a diagram showing the magnetic characteristics of the CoPt hard magnetic layer 16 in the fourth embodiment. In the figure, the vertical axis represents the magnetic field Hc (Oe), and the horizontal axis represents the film thickness (nm) of the ferromagnetic underlayer 15. The film thickness of the CoPt hard magnetic layer 18 is 20 nm. In the figure, characteristic IV shows the case where the ferromagnetic underlayer 15 of the fourth embodiment is made of FePt, and the optimum value of the film thickness of the FePt ferromagnetic underlayer 15 in the fourth embodiment is 2.5 nm or more. I know that there is. As described above, when FePt is used for the ferromagnetic underlayer 15, the range of the optimum film thickness can be further expanded as compared with the case where Fe is used.

  FIG. 7 is a diagram showing the magnetization characteristics of the CoPt hard magnetic layer 18 in the fourth embodiment. In the figure, the vertical axis represents residual magnetization (Gauss), and the horizontal axis represents the film thickness (nm) of the ferromagnetic underlayer 15. In the figure, the characteristic V shows the case where the ferromagnetic underlayer 15 is made of Fe in the first embodiment, and the characteristic VI shows the case where the ferromagnetic underlayer 15 is made of FePt in the fourth embodiment. The thickness of the magnetic layer 18 is assumed to be 20 nm. The characteristic VI also shows that the optimum value of the film thickness of the FePt ferromagnetic underlayer 15 in the fourth example is 2.5 nm or more, and a higher magnetization can be obtained than in the case of the Fe ferromagnetic underlayer 15.

  FIG. 8 is a diagram showing the squareness ratio of the CoPt hard magnetic layer 18 in the fourth embodiment. In the figure, the vertical axis represents the squareness ratio, and the horizontal axis represents the film thickness (nm) of the ferromagnetic underlayer 15. In the figure, characteristic VII shows the case where the ferromagnetic underlayer 15 is made of FePt in the fourth embodiment, and the thickness of the CoPt hard magnetic layer 18 is 20 nm. The characteristic VII also shows that the optimum value of the film thickness of the FePt ferromagnetic underlayer 15 in the fourth example is 2.5 nm or more.

  FIG. 9 is a diagram showing the anodic polarization curve measurement results for FeCr, CoCrPt, CoPt, and FePt, that is, the corrosion resistance. In the figure, the vertical axis represents the pitting potential and the horizontal axis represents the natural potential. As can be seen from the figure, the corrosion resistance of FePt is higher than that of FeCr, CoCrPt, and CoPt, so that it is particularly suitable as the ferromagnetic underlayer 15. As described above, in Patent Document 1, an element having a bcc atomic structure of Cr, Nb, Mo, or Ta is added in order to maintain the bcc structure of Fe as an additive element to Fe. However, these elements other than Cr had poor corrosion resistance and magnetic properties when combined with CoPt.

  In contrast, the present inventors added an element having an atomic structure of fcc such as Pt, Pd, etc. to Fe, but structurally it is not a bcc structure, but the corrosion resistance and magnetic properties when combined with CoPt Has been confirmed experimentally.

  Next, a description will be given of a fifth embodiment of the magnetoresistive head according to the present invention. In the present embodiment, the basic configuration of the magnetoresistive head is the same as that of the first embodiment, and the illustration thereof is omitted. In this embodiment, the ferromagnetic underlayer 15 is made of FeCo alloy, FeCoNi alloy or FeNi alloy to which at least one element selected from the group consisting of Pt, Pd, Ir, Rh and Ru is added instead of Fe. The configuration is different from the first embodiment.

  Next, an embodiment of the magnetic recording / reproducing apparatus according to the present invention will be described. In the embodiment of the magnetic recording / reproducing apparatus, any one of the first to fifth embodiments of the magnetoresistive head is used.

  FIG. 10 is an exploded perspective view of the magnetoresistive head used in this embodiment, and FIG. 11 is a perspective view of the magnetoresistive head with a part removed. 10 and 11, the same parts as those in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted.

  10 and 11, the lead conductor layer 40 includes the ferromagnetic underlayer 15, the hard magnetic layer 16, and the element terminal 17 shown in FIG. After each layer shown in FIG. 10 is formed, a magnetoresistive head is created by cutting to the processing surface 41 shown in FIG. 11 by a known processing. In FIG. 11, reference numeral 42 denotes an electrode, and a sense current is applied to this electrode 42.

  FIG. 12 is a perspective view showing a main part of the recording / reproducing head 100 in which the magnetoresistive head and the inductive head shown in FIGS. 10 and 11 are integrally provided. In FIG. 12, the same parts as those in FIGS. 10 and 11 are denoted by the same reference numerals, and the description thereof is omitted. As the basic configuration of the recording / reproducing head 100, a well-known configuration can be adopted except for the configuration of the lead conductor layer 40 of the magnetoresistive head. Therefore, detailed description thereof is omitted.

  In FIG. 12, 21 is a substrate, 22 is a substrate protective film, 24 is a terminal, and 25 is a magnetic transducer. Reference numeral 51 denotes a recording coil, 52 denotes a recording upper magnetic pole, and 53 denotes a recording gap. Reference numeral 60 denotes a magnetic recording medium, 61 denotes a track width, and 62 denotes a bit length. The magnetoresistive head constitutes the reproducing head unit 101, and the inductive head constitutes the recording head unit 102.

  FIG. 13 is an exploded perspective view showing a main part of an embodiment of the magnetic recording / reproducing apparatus. In the figure, a plurality of magnetic recording media 60 are provided in a housing 70, and the upper portion of the housing 70 is sealed by a lid 71 being screwed. A plurality of arms 74 are provided in the housing 70, and a recording / reproducing head 100 is provided at the tip of each arm 74. Since the basic configuration itself of the magnetic recording / reproducing apparatus shown in FIG. 13 can adopt a well-known configuration, detailed description thereof is omitted.

  The configuration of the recording / reproducing head to which the magnetoresistive head according to the present invention is applied and the configuration of the magnetic recording / reproducing apparatus are not limited to the configurations of the above-described embodiments, but the magnetic according to the present invention. Any recording / reproducing head or magnetic recording / reproducing apparatus having a configuration to which a resistance effect type head can be applied may be used.

  While the present invention has been described with reference to the embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made within the scope of the present invention.

It is sectional drawing which shows the principal part of the conventional magnetoresistive head. It is a figure which shows the characteristic of the ferromagnetic base film of a bcc crystal structure. It is sectional drawing explaining the manufacturing process of 1st Example of a magnetoresistive head. It is sectional drawing which shows the principal part of 1st Example of a magnetoresistive head. It is a figure which shows the magnetic characteristic of the CoPt hard magnetic layer in a 1st and 2nd Example. It is a figure which shows the magnetic characteristic of the CoPt hard magnetic layer in 4th Example. It is a figure which shows the magnetization characteristic of the CoPt hard magnetic layer in 4th Example. It is a figure which shows the squareness ratio of the CoPt hard magnetic layer in 4th Example. It is a figure which shows the corrosion resistance of FeCr, CoCrPt, CoPt, and FePt. It is a disassembled perspective view of the magnetoresistive head used in the present embodiment. It is a perspective view which removes and partially shows the upper part of a magnetoresistive head. FIG. 12 is a perspective view showing a main part of a recording / reproducing head in which the magnetoresistive head and the inductive head shown in FIGS. 10 and 11 are integrally provided. It is a disassembled perspective view which shows the principal part of the Example of a magnetic recording / reproducing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lower shield layer 11 Lower gap layer 12 Magnetoresistive element 13 Resist film 15 Ferromagnetic underlayer 16 Hard magnetic layer 17 Element terminal 18 Upper gap layer 19 Upper shield layer 40 Leading conductor layer 100 Recording / reproducing head 101 Reproducing head part 102 Recording Head

Claims (5)

A stabilizing bias layer for applying a magnetization stabilizing bias magnetic field to the magnetoresistive film of the magnetoresistive element;
A ferromagnetic material constituting the underlayer of the stabilizing bias layer,
The ferromagnetic material is composed of a Fe alloy, a FeCo alloy, a FeCoNi alloy, or a FeNi alloy to which at least one element selected from the group consisting of Pt, Pd, Ir, Rh, Ru, and Au is added. head.   2. The magnetoresistive head according to claim 1, wherein the ferromagnetic body is made of an FePt alloy having a Pt composition of 1 to 25 at%.   The magnetoresistive head according to claim 2, wherein the ferromagnetic body has a film thickness of 2.5 nm or more.   The magnetoresistive head according to claim 1, wherein the stabilizing bias layer is made of a CoPt alloy. A magnetic recording / reproducing apparatus comprising the magnetoresistive head according to claim 1.

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