Magnetic head slider using giant magnetostrictive material

A magnetic head slider includes at least one thin-film magnetic head formed on a trailing surface of the magnetic head slider, and an ABS to be faced a magnetic disk in operation. At least a part of the ABS is made of a giant magnetostrictive material.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnetic head slider using a giant magnetostrictive material, to a magnetic head assembly provided with the magnetic head slider and to a magnetic disk drive apparatus provided with the magnetic head assembly.

2. Description of the Related Art

In a hard disk drive (HDD) apparatus that is one kind of a magnetic disk drive apparatus, a magnetic head slider attached at a top end section of a head support member having a suspension and a support arm aerodynamically flies with keeping a predetermined space or flying height above the surface of a rotating magnetic disk. In this flying state, a thin-film magnetic head formed on the magnetic head slider performs writing of signals to the magnetic disk using magnetic field generated from an inductive write head element, and performs reading of signals by sensing a magnetic field from the magnetic disk using a magnetoresistive effect (MR) read head element. The magnetic effective distance between these magnetic head elements and the magnetic disk surface is defined as a magnetic spacing.

Recently, a track width of a thin-film magnetic head becomes narrower to satisfy the requirements for increasing data storage capacities and recording densities of the HDD apparatus and also the requirement of downsizing of the HDD apparatus. In order to work around lowering in writing ability and reading ability due to narrowing in the track width, the magnetic spacing of the recent thin-film magnetic head is determined to a very small value of about 10 nm.

U.S. Pat. No. 5,991,113 and U.S. Patent Publication No. US2003/0174430A1 disclose a method for precisely controlling such micro magnetic spacing by forming a heater near or in a head element of a magnetic head slider and by thermally expanding or protruding a part of the head element as required. Such method is called as a thermal pole tip protrusion (TPTP) method.

However, according to the conventional magnetic spacing control technique using the TPTP method, since (1) it is necessary to additionally form a heater within a limited and narrow space of the magnetic head slider, (2) it is necessary to additionally form a heater drive and control circuit in the HDD apparatus, and (3) it is necessary to additionally form on the magnetic head slider a wiring member for electrically connecting the heater and an external circuit, not only the configuration of the magnetic head slider becomes complex causing its design to make difficult and its manufacturing cost to increase but also intrinsic read/write characteristics of the thin-film magnetic head deteriorates. Further, due to heat generation of the heater, unwanted temperature increase in the magnetic head slider may be induced.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a magnetic head slider, a magnetic head assembly and a magnetic disk drive apparatus, magnetic spacing control can be performed without additionally forming an electrical-mechanical element such as a heater in the magnetic head slider but with a simple structure of the magnetic head slider.

According to the present invention, a magnetic head slider includes at least one thin-film magnetic head formed on a trailing surface of the magnetic head slider, and an air bearing surface (ABS) to be faced a magnetic disk in operation. At least a part of the ABS is made of a giant magnetostrictive material.

According to the present invention, also, a magnetic head assembly includes the above-mentioned magnetic head slider and a suspension to which the magnetic head slider is fixed, for supporting this magnetic head slider. Here, the magnetic head assembly means an assembly mechanically and electrically assembling a composite thin-film magnetic head or a magnetic head slider having a write head element and a read head element with its support member. More concretely, an assembly of a magnetic head slider and a suspension is in general called as a head gimbal assembly (HGA), an assembly of a magnetic head slider, a suspension and a support arm for supporting the suspension is in general called as a head arm assembly (HAA), and an assembly stacking a plurality of HAAs is in general called as a head stack assembly (HSA).

According to the present invention, further, a magnetic disk drive apparatus includes a magnetic disk and the above-mentioned magnetic head assembly.

Since at least a part of the ABS of the magnetic head slider is made of a giant magnetostrictive material, when the magnetic head slider is flying close to the surface of the magnetic disk, the ABS portions formed by the giant magnetostrictive material protrude toward the magnetic disk surface due to magnetic field applied from the magnetic disk. The magnetic head slider is designed so that sections near the magnetic head elements hit or contact the surface of the magnetic disk due to negative pressure induced depending upon the shape of the ABS when the ABS portions do not protrude. The magnetic field applied from the magnetic disk increases and thus the amount of the protrusion of the ABS increases when the ABS comes closer to the magnetic disk surface. If the protrusion amount increases, the flying height of the magnetic head, that is, a space between the magnetic head elements and the magnetic disk surface increases. As a result, the magnetic spacing can be adequately controlled.

Also, because such magnetic spacing control can be performed without additionally forming an electrical-mechanical element such as a heater in the magnetic head slider, not only simple configuration, easy design and reduced manufacturing cost of the magnetic head slider can be expected but also it is possible to prevent deleterious effect on the intrinsic read/write characteristics of the thin-film magnetic head from occurring. Further, since no heating due to a heater is produced, temperature of the magnetic head slider is never unnecessarily increased.

It is preferred that the at least one thin-film magnetic head is formed on a substrate made of a ceramic material, that a giant magnetostrictive material member is fixed on only a part of the substrate, the part locating at the ABS side, and that the ABS is formed on the giant magnetostrictive material member.

It is also preferred that the at least one thin-film magnetic head is formed on a substrate made of a ceramic material, that a giant magnetostrictive material member is fixed over a whole leading the surface of the substrate, and that the ABS is formed on the giant magnetostrictive material member.

It is further preferred that whole of a substrate is made of a giant magnetostrictive material, and that the at least one thin-film magnetic head and the ABS are formed on the substrate.

It is also preferred that the giant magnetostrictive material is a magnetostrictive material with a raw material of the Laves type cubical crystal (RT2) consisting of lanthanoid R and iron group element T.

It is further preferred that the at least one thin-film magnetic head is a thin-film magnetic head with an inductive write head element and an MR read head element.

It is still further preferred that the suspension includes a resilient flexure to which the magnetic head slider is fixed, and a load beam for supporting the flexure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1schematically illustrates main components of a magnetic disk drive apparatus in a preferred embodiment according to the present invention,FIG. 2illustrates the whole of an HGA,FIG. 3illustrates a magnetic head slider provided at the top end section of the HGA, andFIG. 4schematically illustrates a part of a magnetic head element on an element-formed surface of the magnetic head slider shown inFIG. 3.

InFIG. 1, reference numeral10indicates a plurality of magnetic disks10rotating in operation around a rotation axis of a spindle motor11,12indicates an assembly carriage device for positioning a thin-film magnetic head formed on a magnetic head slider on a track, and13indicates a read/write control circuit for controlling the read/write operations of the thin-film magnetic head, respectively.

The assembly carriage device12has a plurality of drive arms14. These drive arms14are driven by a voice coil motor (VCM)15to rotate around a pivot bearing axis16, and stacked in the direction along the axis16. An HGA17is fixed at the top end section of each drive arm14. The magnetic head slider is attached to each HGA17so that the thin-film magnetic head opposes a surface of each magnetic disk10. Although in the above-description a plurality of the magnetic disks10, drive arms14, HGAs17and magnetic head sliders are mounted in the magnetic disk drive apparatus, each of these may be single in modifications.

As shown inFIG. 2, the HGA is constituted by fixing the magnetic head slider21having the thin-film magnetic head at the top end section of a suspension20, and by electrically connecting one end of a wiring member25to signal electrodes of the magnetic head slider21.

The suspension20mainly consists of a load beam22for generating a load to be applied to the magnetic head slider, a resilient flexure23fixed and supported on the load beam22, a base plate24fixed to the base end section of the load beam22, and the wiring member25formed on the flexure23and the load beam22. The wiring member25has trace conductors and connection pads electrically connected to both end of the respective trace conductors.

It is apparent that the structure of the suspension in the HGA of the present invention is not limited to aforementioned structure. Although it is not shown, a head drive IC chip may be mounted on the suspension20.

As shown inFIG. 3, the magnetic head slider21in this embodiment has a substrate30made of a ceramic material such as AlTiC (alumna (Al2O3)-titanium carbide (TiC)), and a giant magnetostrictive material member31fixed to a part of the substrate30.

As shown inFIG. 4, a composite thin-film magnetic head33consisting of an MR read head element33aand an inductive write head element33bstacked each other, and four signal electrodes34aand34bconnected to these head elements33aand33bare formed on the element-formed surface32of the substrate30or on a trailing surface of the magnetic head slider. The positions of the signal electrodes are not limited to that shown inFIG. 3.

Giant magnetostrictive material members31are fixed on only a part of the substrate30, locating at the ABS and leading surface side. The ABSs are formed on these giant magnetostrictive material members31. More concretely, in this embodiment, a pair of rails31aand31bwith surfaces constituting the ABSs and a pair of islands31cand31dwith surfaces constituting the ABSs are formed on a part of the substrate30at the ABS side. Shapes, positions and the number of these rails and islands are not limited to these illustrated inFIG. 3.

It is desired that the giant magnetostrictive material members31are made of a giant magnetostrictive material such as in this embodiment a magnetostrictive material with a raw material of the Laves type cubical crystal (RT2) consisting of lanthanoid R and iron group element T of iron (Fe), nickel (Ni) or cobalt (Co) for example. Table 1 indicates compositions and magnetostrictive constants of known giant magnetostrictive materials.

FIGS. 5ato5cillustrate flying operations of this magnetic head slider.

As shown inFIG. 5a, when the magnetic head slider21is flying away from the surface of the magnetic disk10, magnetic field from the magnetic disk10is low and thus the ABS portions formed by the giant magnetostrictive material members31do not protrude toward the magnetic disk surface. The ABS is designed so that sections near the magnetic head elements hit or contact the surface of the magnetic disk rotating at a steady rotational speed when the ABS portions do not protrude.

As shown inFIG. 5b, when the magnetic head slider21is flying close to the surface of the magnetic disk10, the ABS portions formed by the giant magnetostrictive material members31protrude toward the magnetic disk surface due to magnetic field applied from the magnetic disk10. The amount of protrusion increases as shown inFIG. 5cwhen the ABS comes closer to the magnetic disk surface. If the protrusion amount increases, the flying height of the magnetic head slider, that is, a space between the magnetic head elements and the magnetic disk surface increases. As a result, crash of the magnetic head element portion against the magnetic disk surface can be prevented from occurring and the magnetic spacing can be adequately controlled.

Leakage magnetic field from the magnetic disk is in general about 500 Oe to 1 kOe. Because the giant magnetostrictive material with a raw material of the Laves type cubical crystal (RT2) consisting of lanthanoid R and iron group element T has a magnetostrictive displacement ratio of about 1200 ppm at the application of a magnetic field of 1 kOe, if the magnetic flux is uniformly applied to this giant magnetostrictive material with 0.1 mm thickness, the flying height can be adjusted in a range up to about 120 nm.

According to this embodiment, such magnetic spacing control can be performed without additionally forming an electrical-mechanical element such as a heater in the magnetic head slider21but with forming only the giant magnetostrictive material members31at the ABS portions. Thus, not only simple configuration, easy design and reduced manufacturing cost of the magnetic head slider can be expected but also it is possible to prevent deleterious effect on the intrinsic read/write characteristics of the thin-film magnetic head from occurring. Also, since no heating due to a heater is produced, temperature of the magnetic head slider21is never unnecessarily increased. Further, since the magnetic response performance of the giant magnetostrictive material members31is extremely quick, excellent disturbance resistance due to the quick response to the applied magnetic field can be expected.

FIGS. 6ato6gillustrate an example of a fabrication process of the magnetic head slider of this embodiment. Hereinafter, a manufacturing process of the magnetic head slider of this embodiment will be described using these figures.

First, as shown inFIG. 6a, many thin-film magnetic heads are fabricated, using the thin-film integration technique, in matrix on a wafer60that is made of a ceramic material such as AlTiC.

Then, as shown inFIG. 6b, the wafer60is cut to separate into bar members61each constituting a plurality of magnetic head sliders juncturally aligned in a line.

Then, as shown inFIG. 6c, a part62of each bar member61at the ABS and leading surface side is removed to form a stepped bar member61′.

Thereafter, as shown inFIG. 6d, a giant magnetostrictive material member63with a plate shape is adhered to this part62. Such giant magnetostrictive material member63is in general fabricated by Czochralski process, but in this embodiment, fabricated by pulverizing giant magnetostrictive material, by molding the pulverized material and by sintering the molded material. The giant magnetostrictive material is fabricated as an iron group element that has a high Curie temperature is added to a main raw material of lanthanoid that has a large magnetostrictive ratio, hydrogen is occluded in a part of the material, and then thus obtained material is sintered under hydrogen environment.

Then, as shown inFIG. 6e, a surface at the ABS side of the bar member61′ with the adhered giant magnetostrictive material member63is lapped to obtain a bar member61″ and a giant magnetostrictive material member63′.

Then, as shown inFIG. 6f, the surface of thus formed giant magnetostrictive material member63′ is etched to form the rails31aand31band the islands31cand31d.

Thereafter, as shownFIG. 6g, the bar member is cut to separate into individual magnetic head sliders21.

FIG. 7illustrates a magnetic head slider in another embodiment according to the present invention.

As shown in the figure, the magnetic head slider21′ in this embodiment has a substrate30′ made of a ceramic material such as AlTiC, and a giant magnetostrictive material member31′ fixed to a part of the substrate30′.

A composite thin-film magnetic head33consisting of an MR read head element33aand an inductive write head element33bstacked each other, and four signal electrodes34aand34bconnected to these head elements33aand33bare formed on the element-formed surface32of the substrate30or on a trailing surface of the magnetic head slider. The positions of the signal electrodes are not limited to that shown inFIG. 7.

In this embodiment, the giant magnetostrictive material member31′ is fixed to the whole surface at the leading side surface of the substrate30′. The ABSs are formed on this giant magnetostrictive material member31′. More concretely, in this embodiment, a pair of rails31a′ and31b′ with surfaces constituting the ABSs and a pair of islands31c′ and31d′ with surfaces constituting the ABSs are formed on the ABS side surface of the substrate30′. Shapes, positions and the number of these rails and islands are not limited to these illustrated inFIG. 7.

Material of the giant magnetostrictive material member31′, and other configurations, operations and advantages of this embodiment are the same as those of the embodiment ofFIG. 1.

FIGS. 8ato8gillustrate an example of a fabrication process of the magnetic head slider of this embodiment. Hereinafter, a manufacturing process of the magnetic head slider of this embodiment will be described using these figures.

First, as shown inFIG. 8a, many thin-film magnetic heads are fabricated, using the thin-film integration technique, in matrix on a wafer80that is made of a ceramic material such as AlTiC.

Then, as shown inFIG. 8b, a back surface of the wafer80is lapped.

Then, as shown inFIG. 8c, a giant magnetostrictive material member81with the same shape and size as this wafer80′ is adhered to the lapped back surface of the wafer80′. Such giant magnetostrictive material member81is in general fabricated by Czochralski process, but in this embodiment, fabricated by pulverizing giant magnetostrictive material, by molding the pulverized material and by sintering the molded material. The giant magnetostrictive material is fabricated as an iron group element that has a high Curie temperature is added to a main raw material of lanthanoid that has a large magnetostrictive ratio, hydrogen is occluded in a part of the material, and then thus obtained material is sintered under hydrogen environment.

Then, as shown inFIG. 8d, the wafer80′ with the adhered giant magnetostrictive material member81is cut to separate into bar members82each constituting a plurality of magnetic head sliders juncturally aligned in a line and a giant magnetostrictive material member83fixed to the whole surface at the leading side surface of the juncturally aligned magnetic head sliders.

Then, as shown inFIG. 8e, a surface at the ABS side of the bar member82with the giant magnetostrictive material member83adhered to the whole surface at the leading side surface is lapped to obtain a bar member82′ and a giant magnetostrictive material member83′.

Then, as shown inFIG. 8f, the surface of thus formed giant magnetostrictive material member83′ is etched to form the rails31a′ and31b′ and the islands31c′ and31d′.

Thereafter, as shownFIG. 8g, the bar member is cut to separate into individual magnetic head sliders21′.

FIG. 9illustrates a magnetic head slider in further embodiment according to the present invention.

As shown in the figure, the magnetic head slider21′ in this embodiment has a substrate31″ whole of which is made of a giant magnetostrictive material.

A composite thin-film magnetic head33consisting of an MR read head element33aand an inductive write head element33bstacked each other, and four signal electrodes34aand34bconnected to these head elements33aand33bare formed on the element-formed surface32of the substrate31″ or on a trailing surface of the magnetic head slider. The positions of the signal electrodes are not limited to that shown inFIG. 9.

In this embodiment, the ABSs are formed on the substrate31″ made of the giant magnetostrictive material member. More concretely, in this embodiment, a pair of rails31a″ and31b″ with surfaces constituting the ABSs and a pair of islands31c″ and31d″ with surfaces constituting the ABSs are formed on the ABS side surface of the substrate31″ made of the giant magnetostrictive material. Shapes, positions and the number of these rails and islands are not limited to these illustrated inFIG. 9.

Material of the giant magnetostrictive material substrate31′, and other configurations, operations and advantages of this embodiment are the same as those of the embodiment ofFIG. 1.

FIGS. 10ato10eillustrate an example of a fabrication process of the magnetic head slider of this embodiment. Hereinafter, a manufacturing process of the magnetic head slider of this embodiment will be described using these figures.

First, as shown inFIG. 10a, many thin-film magnetic heads are fabricated, using the thin-film integration technique, in matrix on a wafer100that is made of a giant magnetostrictive material. Such giant magnetostrictive material substrate100is in general fabricated by Czochralski process, but in this embodiment, fabricated by pulverizing giant magnetostrictive material, by molding the pulverized material and by sintering the molded material. The giant magnetostrictive material is fabricated as an iron group element that has a high Curie temperature is added to a main raw material of lanthanoid that has a large magnetostrictive ratio, hydrogen is occluded in a part of the material, and then thus obtained material is sintered under hydrogen environment.

Then, as shown inFIG. 10b, the wafer100is cut to separate into bar members101each constituting a plurality of magnetic head sliders juncturally aligned in a line.

Then, as shown inFIG. 10c, a surface at the ABS side of the bar member101is lapped to obtain a bar member101′.

Then, as shown inFIG. 10d, the surface of thus formed bar member101′ is etched to form the rails31a″ and31b″ and the islands31c′ and31d′.

Thereafter, as shownFIG. 10e, the bar member is cut to separate into individual magnetic head sliders21′.