JP2000163720A - Shield in reading element of magnetic data head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce magnetic interaction between the shield and magnetic reading element of a magnetic reading head. SOLUTION: A layer 114 composed of an iron-silicon-aluminum alloy is disposed on a seed layer 112 composed of an amorphous alloy to form the objective shield for the reading element of a magnetic data head. The proportion (wt.%) of iron, silicon and aluminum in the iron-silicon-aluminum alloy are selected so that the alloy has both magnetostriction close to zero and distinct crystal magnetic anisotropy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield for a read element in a magnetic data device, and more particularly, to controlling the movement of a domain wall in a shield to control the movement of a shield of a magnetic read head and a magnetic read element. The present invention relates to a shield that reduces magnetic interaction between them.

[0002]

2. Description of the Related Art A magnetoresistive (MR) read head uses an MR element disposed between an upper shield and a lower shield to detect a magnetic flux stored on a magnetic medium such as a disk. Reading magnetically encoded information from the magnetic medium. The read element may be an anisotropic magnetoresistive (AMR) element or a giant magnetoresistive (GMR) stack. The AMR element is
GMR stacks are generally composed of ferromagnetic soft alloys based on iron, nickel or cobalt, while GMR stacks have a multi-layer structure and are generally formed of a non-magnetic material such as copper, silver or gold. And two separate layers formed from a ferromagnetic soft alloy based on iron, nickel or cobalt separated by:

A read element magnetized in the easy axis direction has
It is mounted on the read head such that its easy axis is substantially transverse to the direction of rotation of the disk and parallel to the plane of the disk. Magnetic flux from the surface of the disk causes a rotation of the magnetization vector of the read element, followed by a change in the electrical resistance of the read element. A change in the resistance of the read element can be detected by passing a test current through the read element and measuring the voltage across the read element. This voltage information is then converted to the appropriate format and can be manipulated by external circuitry as needed.

The response curve of a read element compares the voltage across the read element with the magnetic flux received from the disk by the read element. The response curve includes both a linear portion and a non-linear portion, and the read element preferably operates along the linear portion. To cause the read element to operate along this linear portion, the read element is magnetically biased at a bias point located halfway through the linear portion of the response curve.

During a read operation, the upper and lower shields absorb any stray magnetic fields emanating from adjacent tracks and transitions, thereby ensuring that the read element is stored in a particular track of the magnetic medium or disk just below. Read only the information that was sent.

Accordingly, the lower shield is typically formed from a material having a relatively high magnetic permeability. In general, Sendust (85% iron, 9.6% silicon, 5.4% aluminum) is a preferred material for the lower shield according to the prior art because of its near-zero magnetostriction and its processing strength. is there. The read element shielded by Sendust can be easily machined and a slider can be formed on the read element with minimal smearing. Smearing on the read element can cause a short circuit between the read element and the upper or lower shield.

[0007]

Although sendust is a generally preferred material for use as the lower shield of a read head, its near-zero magnetocrystalline anisotropy can cause noise in the read element. There is. Within a typical shield, there are multiple magnetic domains separated from each other by multiple magnetic domain walls. Each domain is magnetized in a direction different from the magnetization of all adjacent domains. Due to the near-zero magnetocrystalline anisotropy of the shield formed from Sendust, the domain walls within the shield formed from Sendust are quite random, but the shape of the shield allows some control over the position of the domain walls. . In addition, the application of an external magnetic field to the lower shield during manufacturing, or the application of an external magnetic field to the lower shield from adjacent tracks or transitions of the magnetic storage medium during operation, both in each domain within the shield. Rotate the magnetization and move the domain. Thus, the domain walls are repositioned by the external magnetic field. Furthermore, due to the randomness of the location of the domain walls, the domain walls generally do not return to their original position after the external magnetic field has been removed.

[0008] The lower shield provides a stray magnetic field to the read element. This stray field mainly affects when the read element is biased. However, as the domain wall moves, these stray fields change, changing not only the read element's responsiveness to signals emanating from the rotating disk, but also the read element's bias point. The overall result is
Noise occurs during the reading operation.

It is known that the introduction of anisotropy into the shield makes the position of the domain wall in the shield more predictable. It is also known that the controlled introduction of anisotropy is virtually impossible. Therefore,
For shield designs that have the advantages of sendust forming shields using shields with crystal magnetic anisotropy, there is a need to reduce read element noise by reducing the movement of domain walls within the shield.

[0010]

According to a first aspect of the present invention, there is provided a shield for a read element of a magnetic data head. The shield comprises a seed layer formed from an amorphous alloy, and a second of an iron-silicon-aluminum alloy disposed on the seed layer having both near-zero magnetostriction and non-zero magnetocrystalline anisotropy. And a layer.

According to a second aspect of the present invention, there is provided a method of forming a shield for a read element of a magnetic data head. The method includes disposing a seed layer of an amorphous alloy and disposing a second layer of an iron-silicon-aluminum alloy having near-zero magnetostriction and non-zero magnetocrystalline anisotropy on the seed layer. And heat treating the shield when the shield is in the presence of a magnetic field oriented in a desired direction of its anisotropic field.

The present invention is a shield having sufficient magnetocrystalline anisotropy for a read element of a recording head. A layer of iron-silicon-aluminum alloy is disposed on the amorphous alloy seed layer to form a shield. The weight percentages (% by weight) of iron, silicon and aluminum in the iron-silicon-aluminum alloy are each set such that the alloy has both near-zero magnetostriction and distinct crystal magnetic anisotropy. The use of an amorphous alloy seed layer further increases the overall magnetocrystalline anisotropy of the shield.

In a preferred embodiment of the iron-silicon-aluminum alloy layer, the weight percent of iron is approximately 81% to 93%.
% And the weight percent of silicon is approximately 6% to 10%.
%, And the weight% of aluminum is approximately 0%.
% To 13%. Most preferably, the weight percentages of iron, silicon and aluminum in the iron-silicon-aluminum alloy layer are approximately 89% and 7.5%, respectively.
And 3.5%.

In a preferred embodiment of the seed layer, the seed layer is formed from a cobalt amorphous alloy or nickel. More preferably, the seed layer is formed from a cobalt-zirconium-tantalum alloy. A more preferred form in which the seed layer is formed from a cobalt-zirconium-tantalum alloy has a weight percentage of cobalt in the seed layer in the range of approximately 70% to approximately 90%;
It has a weight percentage of zirconium in the seed layer approximately equal to the weight percentage of tantalum in the seed layer. Most preferably, the weight percent of cobalt in the seed layer is approximately 90%, and the weight percentages of zirconium and tantalum in the seed layer are each approximately 5%.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, an embodiment of the present invention will be described.
It will be described by way of example only and with reference to the accompanying drawings.

The present invention provides a magnetoresistive sensor having improved stability. It is understood that the source of the noise comes from the magnetic domain walls in both shields (upper and lower shields) of the shield system near the read element.

FIG. 1 shows a magnetoresistive type (MR) according to the present invention.
1 is a plan view of a disk drive system 10 including a read head. The disk drive system 10 includes a magnetic disk 12 rotatably mounted about an axis formed by a spindle 14 in a housing 16. The disk drive system 10 also includes a base 20 for the housing 16.
And includes an actuator 18 pivotable about the axis 22 relative to the disk 14. Cover 24
Partially cover the actuator 18. The drive control device 26 is connected to the actuator 18.
The drive controller 26 can be provided inside the disk drive system 10 or external to the disk drive system 10 by appropriate connection with the actuator 18. The actuator 18 includes an actuator arm assembly 28, a rigid support member 30, and a head gimbal assembly 32. The head gimbal assembly 32 includes a flexure arm 34 connected to the rigid support member 30 and an air bearing slider 36 connected to the flexure arm 34 via a gimbal. The slider 36 supports a magnetoresistive transducer or head for reading data from the disk 12 and writing data to the disk 12.

During operation, drive control 26 receives positional information indicating the portion of disk 12 to be accessed. The drive controller 26 receives the position information from any of an operator, a host computer, or another suitable controller. Based on the position information, the drive control device 26 sends a position signal to the actuator 18. The position signal causes actuator 18 to pivot about axis 22. As a result, the slider 36 moves radially on the surface of the disk 12 in a substantially arcuate path indicated by the arrow 38. The drive control 26 and the actuator 18 operate in a closed loop negative feedback configuration such that the transducer carried by the slider 36 is located at a desired location on the disk 12. Once the transducer is properly positioned, the drive control 26
Performs a desired read or write operation.

FIG. 2 is a sectional view of the magnetic read / write head 50 and the magnetic disk 12 taken along a plane perpendicular to the air bearing surface 54 of the read / write head 50. FIG.
The magnetic read / write head 50 and its arrangement with respect to the magnetic disk 12 are shown. The air bearing surface 54 of the magnetic read / write head 50 faces the disk surface 56 of the magnetic disk 12. The magnetic disk 12 moves or rotates relative to the magnetic read / write head 10 in the direction indicated by arrow A. The space between the air bearing surface 54 and the disk surface 56 is
It is preferable that the distance be as small as possible, as long as contact with the magnetic disk 12 is avoided. This contact will destroy both the magnetic read head 50 and the magnetic disk 12 in most cases.

The read section of the magnetic read / write head 50 includes a lower gap layer 58, an upper gap layer 60, and a metal connection layer 6.
2, including a lower shield 64, an upper shield 66, and a reading element 68. The read gap 70 is formed on the air bearing surface 54 between the terminal ends of the lower gap layer 58 and the metal connection layer 62. Metal connection layer 62
Is disposed between the lower gap layer 58 and the upper gap layer 60. The read element 68 is disposed between the lower gap layer 58 and the terminal end of the metal connection layer 62.

The write portion of the magnetic read / write head 50 includes a lower pole 66, a write gap layer 72, an upper pole 74,
It is configured to include the conductive coil 76 and the polymer layer 78. Write gap 80 is formed on air bearing surface 54 by write gap layer 72 between the terminal ends of upper pole 74 and lower pole 66. An electrically conductive coil 76 is provided to create a magnetic field in the write gap 80 and is disposed in the polymer layer 78 between the upper pole 74 and the write gap layer 72. Although FIG. 2 shows a single layer conductive coil 76, it is understood that multiple layers of conductive coil can be used in the present technology, separated by several polymer layers. The magnetic read / write head 50 can be configured such that the component 66 serves as the upper shield 66 in the read section and the lower pole 6 in the write section.
6 is a merged MR head also used as 6. When the magnetic read / write head 50 is a piggyback MR head, the upper shield 66 and the lower pole 66 are separated layers.

FIG. 3 is a hierarchical diagram of the magnetic read / write head 50. FIG. 3 shows the arrangement of magnetically important components of the magnetic read / write head 50 along the air bearing surface 54 of the magnetic read / write head 50 shown in FIG. As shown. In FIG. 3, all layers for spacers and for insulation have been omitted for clarity. The lower shield 64 and the upper shield 66 are spaced apart to provide a location for the reading element 68. The reading element 68 has two passive areas formed in a portion of the reading element 68 that is located adjacent to the metal connections 62A and 62B.
The active area of the reading element 68 is formed in a part of the reading element 68 which is arranged between two passive areas of the reading element 68. The active area of the reading element 68 forms a reading sensor width.

The read element 68 is preferably a magnetoresistive element or a giant magnetoresistive stack. Magneto-resistive elements are generally formed from a ferromagnetic material whose resistance varies in response to an external magnetic field, preferably a magnetic field from a magnetic medium or disk. By supplying an inspection current to such a magnetoresistive element, a change in the resistance of the magnetoresistive element can be measured in an external circuit, and can be used when decoding data stored on a magnetic medium or a magnetic disk. it can. Giant magnetoresistive stacks work similarly but provide a more pronounced magnetoresistive effect. Giant magnetoresistive stacks are generally formed from three layers: a ferromagnetic free layer, a ferromagnetic pinned layer, and a non-magnetic spacer layer disposed between the free and pinned layers. Is done. The pinned magnetization of the pinned layer remains constant while the free magnetization of the free layer rotates freely in response to an external magnetic field, ie, a transition from the magnetic disk. The resistivity of such giant magnetoresistive stacks varies as a function of the angle between the direction of the open magnetization and the direction of the fixed magnetization.

FIG. 4 is a partial perspective view of a magnetic read head 90 that generally includes a lower shield 92, an upper shield 94, and a read element 96 disposed between the lower shield 92 and the upper shield 94. The magnetic read head 90 includes an air bearing surface 98.

In the prior art application, the lower shield 92
Have been formed in several different shapes, such as circular, square, rectangular, trapezoidal, or combinations thereof. FIG.
, The lower shield 92 has a rectangular parallelepiped shape including a first surface 100 indicated by a dotted line adjacent to the reading element 96 and a second surface 102 opposite to the first surface. ing. The third surface 104 indicated by the dotted line is on the opposite side of the fourth surface 106 so that the third surface 104 and the fourth surface 106 connect the first surface 100 to the second surface 102. positioned. For ease of explanation, the magnetic read head 90 and its components shown in FIG.
2. The thickness of the upper shield 94 and the reading element 96 are exaggerated. The upper shield 98 has the same shape as the lower shield 94. The dotted line of the upper shield 98 is not shown for clarity.

In the application of the prior art, sendust (iron 85
%, Silicon 9.6%, and aluminum 5.4%)
Was a suitable material for the read element lower shield because it has substantially no magnetostriction and has high magnetic permeability and high magnetic flux density. In addition, the processing strength of Sendust allows the read element shielded by Sendust to be easily processed to form a slider with minimal smearing on the read element. This allows
The potential for short circuits between the read element and the upper or lower shield is minimized.

In a typical shield, there are a plurality of magnetic domains separated from each other by a plurality of magnetic domain walls. Each domain has a magnetization oriented in a different direction than the magnetization of all adjacent domains. Since Sendust has a near zero magnetic crystal anisotropy, the domain walls in a shield made of Sendust are quite random, but the shape of the shield allows some control over the placement of the domain walls. In addition, the application of an external magnetic field to the upper or lower shield from adjacent tracks or transitions of the storage medium during manufacture or during operation, rotates the magnetization of each domain within the shield and moves the domain. , Increase, and / or reduce. In this way, the domain walls are relocated by the external magnetic field. further,
Due to the random nature of the domain wall arrangement, the domain walls generally do not return to their original position after the external magnetic field has been removed.

The upper and lower shields provide a stray magnetic field on the read element. These stray fields mainly affect when the read element is biased. However, as the domain wall moves, these stray magnetic fields change, thereby changing not only the read element's responsiveness to signals emanating from the storage medium, but also the read element's bias point. The overall result is noise during the reading operation.

It has been found that the introduction of anisotropy into the shield makes the placement of the domain walls within the shield more predictable, but differs from materials such as Sendust which have a near zero magnetocrystalline anisotropy. Controlling anisotropy has also proven to be virtually impossible.

FIG. 5 is a cross-sectional view of a shield 110 designed according to the present invention. The shield 110 has all the advantages of a shield formed using Sendust, namely:
It has processing strength, substantially zero magnetostriction, high magnetic permeability and high magnetic flux density, but, unlike prior art shields, has significant anisotropy. The shield 110 is formed by depositing a layer 114 on the seed layer 112. Layer 114 is formed from an iron-silicon-aluminum alloy having the same components as Sendust, magnetostriction near zero, and a finite value of magnetocrystalline anisotropy. The seed layer 112 is formed from an amorphous alloy having a very large anisotropy.

The seed layer 112 is preferably formed of a cobalt-amorphous alloy (for example, cobalt-hafnium-niobium or cobalt-zirconium-tantalum) or nickel, and is preferably formed of a cobalt-zirconium-tantalum alloy. Is most preferred. Preferably, the weight percent of cobalt is in the range of about 70% to about 90%, with the balance being equal weight percent.
And zirconium and tantalum. The preferred embodiment has a weight percent of cobalt equal to approximately 90% and a weight percent of zirconium and tantalum each equal to approximately 5%. The seed layer 112 has a thickness of about 10 nm.
Preferably, it has a thickness in the range of from about 100 nm to about 100 nm.

FIG. 6 is a composition diagram of an iron-silicon-aluminum alloy including plots for the following parameters. That is, the parameter is the initial permeability μ0 = MA
X, magnetostriction λs = 0, and crystal anisotropy constant K = 0. Figure 6 shows Ferromagnetis by Richard M Boz-orth.
This is taken from FIG. 4.32 of m 100 (1978). The iron percentage for a particular composition of iron-silicon-aluminum alloy is shown on axis 120 and the silicon percentage is
2 and the percentage of aluminum is shown on axis 124. The composition selected for the present invention is located near both the parameter plot 126 for the magnetostriction λs equal to zero and the parameter plot 128 for the maximized initial permeability μ0, and
It should be located far from the parameter plot 130 for a crystal anisotropy constant of 0.18. Iron weight%
Is in the range of about 81% to about 93%, the weight% of silicon is in the range of about 6% to about 10%, and the weight% of aluminum is in the range of about 0% to about 13%. Preferably it is. In a preferred embodiment, layer 114 comprises approximately 8
It is preferably formed from a composition 132 having a weight percent of iron equal to 9%, a weight percent of silicon equal to approximately 7.5%, and a weight percent of aluminum equal to approximately 3.5%. The iron / silicon / aluminum alloy layer 114 is approximately 1
It preferably has a thickness in the range from μm to about 3 μm.

To set the anisotropic field, the shield 110
Is heat treated at 450 degrees Celsius for up to 3 hours in the presence of a magnetic field oriented in the desired direction for its anisotropic field.

FIG. 7 shows a shield according to the present invention.
3 is a plot of an easy axis hysteresis loop 140 and a hard axis hysteresis loop 142 along both the easy and hard axis, respectively.
The applied magnetic field H is shown along the abscissa, and the magnetic flux B of the shield is shown along the ordinate. The anisotropy constant of the shield according to the present invention extrapolates the slope of the hard axis hysteresis loop 142 where the magnetic flux B equals zero, and this slope overlaps the saturation flux of the hard axis hysteresis loop 142. It can be determined by stretching to The value of the magnetic field H at this position is an anisotropic constant. As is evident in FIG. 7, the anisotropy constant of the shield according to the invention is not zero.

Hysteresis loop 14 in the easy axis direction
The form factor SR _E of zero (comparing the value of the magnetic flux B when the magnetic field H is equal to zero with the value of the magnetic flux B when the magnetic field H is at its maximum value) is approximately equal to 0.99. And the shape ratio SR of the hysteresis loop 142 in the hard axis direction.
_H is approximately equal to 0.16. Coercive force H in the direction of hard magnetization
_{While CH} is approximately equal to 0.18, the coercive force H _{CE in the} easy axis direction is approximately equal to 0.44. It is generally preferred that the square ratio for the easy axis is approximately equal to 1 and the square ratio for the hard axis is approximately equal to zero. It is also generally preferred that the coercivity on the hard axis be smaller than the coercivity on the easy axis.

FIG. 8 is a cross-sectional view of a shield 150 according to the present invention that operates in the absence of an external magnetic field. The shield 150 includes closed magnetic domains 152A,
52B, 152C and 152D and the magnetic domain 154
A, 154B, 154C, and magnetic domain walls 156A and 156B. Magnetization 158A-158G
Represents the magnetization in each magnetic domain. Due to the crystal magnetic anisotropy of the shield 150, the domain wall 156A
And 156B are oriented in the direction of the easy axis of the shield 150. Magnetic domain walls 156A and 156B
Each have the property of constantly settling down to the minimum possible energy state. The minimum possible energy state in this case corresponds to the easy axis of the shield 150.

FIG. 9 shows a shield 1 according to the present invention which operates in a state where an external magnetic field from a magnetic storage medium acts.
It is sectional drawing of 50. The external magnetic field is represented by arrow 162. The external magnetic field 162 has magnetizations 158A to 158C.
Is rotated in a direction toward the direction of the external magnetic field 162.
As shown in FIG. 9, the external magnetic field 162 is operating downward. Therefore, the magnetizations 158A to 158C rotate downward. However, in FIG. 9, the magnetization 1 corresponding to the closed magnetic domains 152A to 152D respectively.
It can be confirmed that 58D to 158G do not rotate in the presence of the external magnetic field 162. Magnetization 158D ~ 15
8G does not rotate because these magnetizations are initially arranged parallel or anti-parallel to the external magnetic field 162.
With such a parallel scheme, the magnetizations 158D-158
G does not rotate but closed magnetic domains 152A-152
The size and shape of D vary. Magnetization 158D and 1
Closed magnetic domains 152A and 152D where 58G are initially respectively arranged parallel to the external magnetic field 162 include:
The dimensions increase while the closed magnetic domains 152B and 152C, in which the magnetizations 158E and 158F are initially arranged antiparallel to the external magnetic field 162, respectively, decrease in size. A change in the size of the closed magnetic domains 152A-152D changes the shape of the magnetic domains 154A-154C, but does not move the position of the magnetic domain walls 156A and 156B in a direction toward the read element 160. With the shield formed by the sendust according to the prior art, the initial arrangement of the magnetic domain cannot be controlled,
As a result, the position of the magnetic domain wall could not be controlled. However, the shield 150 has anisotropy that allows for control of the initial placement of the magnetic domains. Therefore, the magnetic domain walls 156A and 156B
Is controlled so as not to move in the direction toward the reading element 160. Each magnetic domain wall 156A and 15
6B has the property of constantly trying to settle in the lowest possible energy state, so the magnetic domain wall 156A
Is fixedly maintained between the closed magnetic domains 152A and 152B, and the magnetic domain wall 156B is fixedly maintained between the closed magnetic domains 152C and 152D. The minimum possible energy state in this case corresponds to the state in which the magnetic domain wall 156A or 156B has the minimum possible length. Therefore, the magnetic domain wall 1
56A and 156B remain in a low and constant energy state located between the intersections of the triangular closed magnetic domains 152A-152D.

A further advantage of the present invention is that shields designed according to the present invention exhibit a high level of magnetic permeance when subjected to alternating magnetic fields in excess of 100 megahertz in the hard axis direction.

The present invention achieves a single magnetic domain state near the magnetoresistive read element of a magnetic recording head,
This makes it possible to read back stable and repeatable data from the magnetic storage medium. The present invention
The movement area of the domain walls of the shield is limited to avoid interaction with these domain wall reading elements. This is achieved by an anisotropic shield that allows for controlled placement of the magnetic domains. The present invention
Although two easy axis domain walls 156A and 156B are disclosed, additional easy axis domain walls may be provided depending on the size of the lower shield.

The foregoing description has been provided by way of example only, and it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a disk drive storage system.

FIG. 2 is a sectional view of a magnetic read / write head and a magnetic disk taken along a plane perpendicular to the air bearing surface of the read / write head.

FIG. 3 is a hierarchical diagram of a magnetic read / write head.

FIG. 4 is a partial perspective view of a magnetic read / write head including a lower shield, a magnetic read element, and an upper shield.

FIG. 5 is a sectional view of a shield according to the present invention.

Fig. 6 Ferromagnetism 10 by Richard M Bozorth
0 Composition diagram of iron-silicon-aluminum alloy, including parameter plots, taken from Figure 4.32 of (1978)

FIG. 7 is a plot of a hysteresis loop for both the easy axis and the hard axis in the shield according to the present invention.

FIG. 8 operates in the absence of an external magnetic field;
Sectional view of the lower shield according to the present invention

FIG. 9 is a cross-sectional view of the lower shield according to the present invention, which operates in a state where an external magnetic field from the magnetic storage medium acts.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Disk drive system 12 Magnetic disk 18 Actuator 26 Drive control device 36 Slider 50 Magnetic read / write head 58 Lower gap layer 60 Upper gap layer 62 Metal connection layer 64 Lower shield 66 Upper shield (lower pole) 68 Reading element 72 Writing Gap layer 74 Upper pole 76 Conductive coil 78 Polymer layer 90 Magnetic read head 92 Lower shield 94 Upper shield 96 Reading element 110 Shield 112 Seed layer 150 Shield 152 Closed magnetic domain 154 Magnetic domain 156 Magnetic domain wall 158 Magnetization 160 Read element 162 External magnetic field

Claims (14)

[Claims] 1. A shield for a read element of a magnetic data head, comprising: a seed layer formed from an amorphous alloy; and a magnetostriction near zero and a non-zero magnetocrystalline anisotropy disposed on the seed layer. A second layer of an iron-silicon-aluminum alloy having both: and a shield comprising: 2. The shield according to claim 1, wherein the amorphous alloy forming the seed layer is selected from the group consisting of a cobalt amorphous alloy and nickel. 3. The shield according to claim 1, wherein said seed layer is formed of a cobalt-zirconium-tantalum alloy. 4. The shield according to claim 3, wherein the weight percentage of cobalt in said seed layer is in the range of approximately 70% to 90%. 5. The shield according to claim 3, wherein the weight percentage of zirconium in the seed layer is substantially equal to the weight percentage of tantalum in the seed layer. 6. The weight percentage of cobalt in the seed layer is approximately 90%, the weight percentage of zirconium in the seed layer is approximately 5%, and the weight percentage of tantalum in the seed layer is approximately 5%. The shield according to claim 3, wherein the shield is provided. 7. The weight percentage of iron in the second layer is in a range of approximately 81% to 93%, and the weight percentage of silicon in the second layer is in a range of approximately 6% to 10%. The shield according to any one of claims 1 to 6, wherein the weight percentage of aluminum in the second layer is in a range of approximately 0% to 13%. 8. The weight percentage of iron in the second layer is approximately 89%, the weight percentage of silicon in the second layer is approximately 7.5%, and the aluminum in the second layer is approximately 80%. 8. The shield according to claim 1, wherein the weight percentage of the shield is approximately 3.5%. 9. The method according to claim 8, wherein said seed layer has a thickness of about 10 nm to 1000 nm.
The shield according to any one of claims 1 to 8, wherein the shield has a thickness in the range of: 10. The method according to claim 1, wherein said second layer has a thickness in the range of approximately 1 μm to 3 μm.
The shield according to any one of claims 9 to 9. 11. A method for forming a shield for a read element of a magnetic data head, comprising: disposing a seed layer of an amorphous alloy; and providing near-zero magnetostriction and non-zero crystalline magnetic anisotropy. Disposing a second layer of an iron-silicon-aluminum alloy over the seed layer; and placing the shield in the presence of a magnetic field in which the shield is oriented in a desired direction of its anisotropic field. Sometimes heat treating; and a method comprising: 12. The method according to claim 1, wherein the amorphous alloy forming the seed layer is selected from the group consisting of a cobalt amorphous alloy and nickel.
The method of claim 1. 13. The weight percentage of iron in said second layer is in the range of approximately 81% to 93%, and the weight percentage of silicon in said second layer is in the range of approximately 6% to 10%. 13. The method of claim 11 or claim 12, wherein the weight percentage of aluminum in the second layer is in the range of approximately 0% to 13%. 14. A magnetic data head comprising: a read element; and the shield according to claim 1.