JP2009158676A - Piezoelectric element, magnetic head assembly and magnetic recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a piezoelectric element which has a relatively simple structure, can be easily manufactured and enables a magnetic head to be positioned at high speed and with high accuracy; a magnetic head assembly using the piezoelectric element; and a magnetic recording device. <P>SOLUTION: A slider provided with the magnetic head is joined to a suspension arm through a piezoelectric element 20. The piezoelectric element 20 includes an element body 30 made of a ferroelectric film and a plurality of buried electrodes 31a and 31b buried in grooves arrayed in the width direction of the element body 30 to section the element body 30 into a plurality of blocks. Axes of polarization of adjacent blocks are parallel to the width direction and in directions opposite from one another. Further, the adjacent blocks are applied with voltages which are parallel to the width direction and in directions opposite from each other by the buried electrodes 31a and 31b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a piezoelectric element suitable for highly accurate position control of a magnetic head in a magnetic recording apparatus, and a magnetic head assembly and a magnetic recording apparatus using the piezoelectric element.

  In recent years, magnetic recording devices (hard disk devices) have been widely used not only for computers but also for home appliances such as portable music players and hard disk video recorders (HDD recorders). In addition, along with the improvement in performance of these devices, there is a demand for an increase in the capacity of the magnetic recording apparatus, and the recording capacity per magnetic disk is remarkably increased.

  In order to increase the recording capacity without changing the size of the magnetic disk, the number of tracks per unit length (track per inch: TPI) must be increased, that is, the track width should be narrowed and arranged at a high density. Is essential. In response to the narrowing and high density of tracks, there is also a demand for miniaturization of magnetic heads (recording elements and reproducing elements) for recording and reproducing data on and from a magnetic disk.

  The magnetic head is disposed on an end face of a substantially rectangular parallelepiped member called a slider. In a conventional magnetic recording apparatus, a suspension arm that supports a slider is rotated by a magnetic actuator (voice coil motor) within a predetermined angle range in a direction parallel to the surface of the magnetic disk, thereby positioning the magnetic head. However, if the track density is increased for the reasons described above, it has become difficult to precisely control the positioning of the magnetic head by simply rotating the suspension arm with an electromagnetic actuator. Therefore, in addition to position control by a voice coil motor, it has been proposed to finely adjust the position of a slider (magnetic head) using a microactuator.

Patent Document 1 describes a magnetic recording apparatus in which a slider is slightly displaced by an electrostatic actuator. In Patent Document 1, an electrostatic actuator configured by combining a fixed electrode and a movable electrode formed in a comb shape is disclosed. Patent Document 2 describes an actuator having a structure in which a piezoelectric element is attached to each of a pair of arms contacting both sides of a slider, and the slider is slightly displaced by deforming the arm by these piezoelectric elements. Further, Patent Document 3 discloses an actuator having a structure in which a piezoelectric element that is driven in a shear mode (d15 mode) and a conductor layer are stacked, and a movable member (thin plate) is further bonded thereon, and the actuator is a suspension arm. And a magnetic recording device having a structure arranged in the middle of the above.
JP-A-8-180623 JP 2002-74870 A Japanese Patent No. 3420915

  However, since the electrostatic actuator described in Patent Document 1 has a complicated structure, it is difficult to manufacture and mount it, and it is considered that the manufacturing cost of the magnetic head assembly increases and the manufacturing yield decreases. The actuator described in Patent Document 2 is also considered to have many adhesion points and a complicated structure, resulting in an increase in manufacturing cost.

  The actuator described in Patent Document 3 has a drawback that the displacement amount of the actuator itself is small. Therefore, in Patent Document 3, an actuator is arranged in the middle of the suspension arm to increase the displacement of the slider (magnetic head). However, since the distance between the actuator and the slider is increased, the high-speed response is reduced.

  An object of the present invention is to provide a piezoelectric element that has a relatively simple structure, can be easily manufactured, and can position a magnetic head at high speed and high accuracy, and a magnetic head assembly and a magnetic element using the piezoelectric element. It is to provide a recording device.

  According to an aspect of the present invention, there is provided an element body made of a piezoelectric film, and a plurality of embedded electrodes embedded in grooves arranged in the width direction of the element body and dividing the element body into a plurality of blocks. The polarization axes of adjacent blocks are parallel to the thickness direction of the element body, and the polarization directions of the adjacent blocks are opposite to each other, and the adjacent blocks are parallel to the width direction by the embedded electrode. A piezoelectric element to which voltages in opposite directions are applied is provided.

  According to another aspect of the present invention, there is provided a magnetic head assembly including a slider on which a magnetic head for recording or reproducing data on a magnetic recording medium is formed, and a piezoelectric element bonded to the slider. A piezoelectric element is composed of an element main body made of a piezoelectric film and a plurality of embedded electrodes embedded in grooves arranged in the width direction of the element main body and partitioning the element main body into a plurality of blocks. The polarization axes of the adjacent blocks are parallel to the thickness direction of the element body, and the polarization directions of the adjacent blocks are opposite to each other. The adjacent blocks are parallel to the width direction by the embedded electrodes and are opposite to each other. A magnetic head assembly is provided in which a directional voltage is applied.

  Further, according to another aspect of the present invention, a magnetic recording medium, a slider having a magnetic head formed thereon, a suspension arm that supports the slider, and the suspension arm is driven to move the slider to the magnetic recording medium. An actuator that moves in the radial direction; a piezoelectric element that is disposed between the slider and the suspension arm; and that displaces the slider in the radial direction of the magnetic recording medium; and controls the electromagnetic actuator and the piezoelectric element, and An electronic circuit unit that records and reproduces data to and from the magnetic recording medium via a magnetic head, and the piezoelectric element includes an element body made of a piezoelectric film, and grooves arranged in the width direction of the element body A plurality of embedded electrodes embedded in the element body and dividing the element body into a plurality of blocks. The polarization axes of the matching blocks are parallel to the thickness direction of the element body, and the polarization directions of the adjacent blocks are opposite to each other. The adjacent blocks are parallel to the width direction by the buried electrode and are mutually There is provided a magnetic recording apparatus to which a reverse voltage is applied.

  In the piezoelectric element of the present invention, the piezoelectric film is partitioned into a plurality of blocks by a plurality of embedded electrodes arranged in the width direction. Adjacent blocks are polarized in parallel to the thickness direction and in opposite directions. Adjacent blocks are applied with voltages in parallel with each other in the width direction and in opposite directions by the embedded electrodes. As a result, a shearing stress is generated in adjacent blocks. In this case, if the applied voltage is constant, the amount of displacement is related to the ratio between the distance L between the buried electrodes and the length T in the thickness direction of the buried electrodes. Therefore, the amount of displacement can be increased by setting a large ratio between the distance L between the embedded electrodes and the length T in the thickness direction of the embedded electrodes.

  In the magnetic head assembly according to the present invention, the piezoelectric element having the above-described structure is bonded to the slider provided with the magnetic head. Therefore, the distance between the piezoelectric element and the slider is extremely short, and the slider (magnetic head) is moved at high speed. And it can be displaced with high accuracy. Accordingly, it is possible to deal with a magnetic disk having a narrow track width and a high density, and it is possible to further increase the capacity of the magnetic recording apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a plan view showing a configuration of a magnetic recording device (hard disk device) according to an embodiment of the present invention.

  The magnetic recording apparatus 10 includes a disk-shaped magnetic disk (magnetic recording medium) 11, a spindle motor (not shown) that rotates the magnetic disk 11, and a magnetic head (recording element and reproducing element) in the housing. The slider 12, the suspension arm 13 that supports the slider 12, the voice coil motor 14 that drives the suspension arm 13 to move the slider 12 in the radial direction of the magnetic disk 11, and the spindle motor and the voice coil motor 14 are driven. An electronic circuit unit 15 that controls and records and reproduces data with respect to the magnetic disk 11 via the magnetic head is provided. The slider 12 is disposed on the surface of the suspension arm 13 on the magnetic disk 11 side. Further, in the magnetic recording apparatus of the present embodiment, a piezoelectric element (actuator) that slightly displaces the position of the slider 12 in the radial direction of the magnetic disk 11 is disposed between the suspension arm 13 and the slider 12 as will be described later. ing.

  In the magnetic recording apparatus 10 configured as described above, when the magnetic disk 11 is rotated at a high speed by the spindle motor, the slider 12 slightly floats from the surface of the magnetic disk 11 due to the air flow generated by the rotation of the magnetic disk 11. Then, the slider 12 is moved in the radial direction of the magnetic disk 11 by the voice coil motor 14, and the position of the slider 12 is finely adjusted by the piezoelectric element, and the magnetic head is arranged to face a desired track. Thereafter, data is recorded on and reproduced from the magnetic disk 11 via the magnetic head.

  FIG. 2 is a perspective view showing the suspension arm 13, the slider 12 attached to the suspension arm 13, and the piezoelectric element 20 (magnetic head assembly).

  The slider 12 is a substantially rectangular parallelepiped member formed of a material such as Altic (alumina-titanium carbide), and is attached to the surface of the suspension arm 13 on the magnetic disk 11 side via the piezoelectric element 20. A magnetic head 17 is provided on one end surface of the slider 12.

  In FIG. 2, the magnetic head 17 is schematically shown. The actual magnetic head 17 includes a recording element that writes data to the magnetic disk 11 and a reproducing element that reads data from the magnetic disk 11. The recording element is a kind of electromagnet composed of a coil and a magnetic pole, and generates a magnetic field corresponding to a write current supplied to the coil toward the magnetic disk 11. As the reproducing element, for example, a magnetoresistive element such as an MR (Magneto Resistive) element, a GMR (Giant Magneto Resistive) element, or a TMR (Tunnel Magneto Resistive) element whose resistance value changes according to the magnetic field generated from the magnetic disk 11 is used. Is done.

  Reference numeral 18 in FIG. 2 denotes electrodes, and these electrodes 18 are electrically connected to the magnetic head 17 (recording element and reproducing element) via wiring formed in the slider 12. In addition, these electrodes 18 are electrically connected to wiring (not shown) provided on the surface of the suspension arm 13 through fine metal wires (bonding wires: not shown).

  In the present embodiment, as shown in FIG. 2, a piezoelectric element (microactuator) 20 is disposed between the slider 12 and the suspension arm 13. An electrode (collective electrode described later) of the piezoelectric element 20 is also electrically connected to a wiring provided on the surface of the suspension arm 13 through a thin metal wire (not shown). As will be described later, the piezoelectric element 20 is driven in the d15 mode, and the slider 12 is slightly displaced in the radial direction of the magnetic disk 11 (direction indicated by an arrow in FIG. 2).

  3A is a plan view showing the piezoelectric element 20, and FIG. 3B is a cross-sectional view taken along the line II of FIG. 3A.

The piezoelectric element 20 is a ferroelectric material such as PZT (lead zirconate titanate: Pb (Zr, Ti) O ₃ ) or PLZT (lead lanthanum zirconate titanate: (Pb, La) (Zr, Ti) O ₃ ). In this structure, embedded electrodes 31a and 31b are embedded in a comb-like shape between element bodies 30 having a rectangular parallelepiped shape. Collective electrodes 32a and 32b are formed on the outer periphery of the element body 30, and the odd-numbered embedded electrodes 31a from the right side of FIG. 3A are connected to one of the collective electrodes 32a, and the even-numbered embedded electrodes 31b. Is connected to the other collective electrode 32b. The collective electrodes 32a and 32b are electrically connected to the wiring provided on the suspension arm 13 through the fine metal wires as described above.

  The longitudinal length L1 of the element body 30 is, for example, 800 μm, the lateral length W1 is, for example, 700 μm, and the thickness T1 is, for example, 100 μm. Further, the vertical length L2 of the embedded electrodes 31a and 31b is, for example, 650 μm, the width W2 is, for example, 20 μm, and the thickness T2 is, for example, 80 μm. Furthermore, the distance L3 between the embedded electrodes 31a and 31b is, for example, 60 μm.

An insulating film 33 made of alumina (Al ₂ O ₃ ), for example, is formed on the element body 30 to a thickness of 5 μm, for example. An adhesive is applied to the upper surface of the insulating film 33 to bond the piezoelectric element 20 and the suspension arm 13 together.

  In the present embodiment, the piezoelectric element 20 is driven in the d15 mode (shear mode). The d15 mode is a mode in which a voltage is applied in a direction perpendicular to the polarization axis (direction at the time of polarization processing) to displace about an axis orthogonal to both the polarization axis and the voltage application direction.

  4A is a top view schematically showing the piezoelectric element 20 when no voltage is applied, and FIG. 4B is a cross-sectional view thereof. FIG. 5A is a top view schematically showing the piezoelectric element in a state where a voltage is applied, and FIG. 5B is a cross-sectional view thereof. In these FIG. 4 and FIG. 5, the white arrow indicates the direction of the polarization axis, and the black arrow indicates the voltage application direction. 4 and 5, the same components as those in FIG. 3 are denoted by the same reference numerals. In the following description, the ferroelectric blocks delimited by the electrode 31a and the electrode 31b are each called a ferroelectric block.

  In this embodiment, as shown by the white arrow in FIG. 4B, the polarization process is performed so that the polarization axes of adjacent ferroelectric blocks are parallel to the thickness direction and opposite to each other. Is done. When a voltage is supplied to the collective electrodes 32a and 32b, as shown by black arrows in FIGS. 5A and 5B, adjacent ferroelectric blocks are connected to the collective electrodes 32a and 32b and the embedded electrodes 31a and 31b. Thus, voltages parallel to the width direction and opposite to each other are applied. As a result, stress in the opposite direction, that is, shearing stress is generated in the adjacent ferroelectric blocks, and the piezoelectric element 20 is deformed so that the cross section becomes a parallelogram as shown in FIG. As a result, the slider 12 bonded to the lower side of the piezoelectric element 20 moves in the diameter direction (track width direction) of the magnetic disk 11 (see FIG. 2).

  6 and 7 are cross-sectional views showing the method of manufacturing the piezoelectric element 20 of this embodiment in the order of steps.

  First, the steps shown in FIGS. 6A and 6B will be described. First, as shown in FIG. 6A, a photoresist is applied on the substrate 40 to form a photoresist film 41. The substrate 40 only needs to have a flat surface, and the material and the like are not particularly limited. Further, the thickness of the photoresist film 41 is, for example, 100 to 200 μm.

  Thereafter, the photoresist film 41 is selectively exposed with a desired pattern of the embedded electrodes 31a and 31b (see FIG. 3A), and then developed, and the photoresist film 41 is exposed from the photoresist as shown in FIG. 6B. A projection 42 is formed. In FIG. 6B, the substrate 40 is not exposed, but the substrate 40 may be exposed between the protrusions 42. In accordance with the size of the embedded electrodes 31a and 31b described above, the protrusion 42 has a width of, for example, 20 μm, a height of, for example, 80 μm, and a length of, for example, 650 μm. The interval between the protrusions 42 is set to 60 μm, for example. For example, i-line, KrF laser, or X-ray is used for exposure of the photoresist film 41.

  Next, the process of FIG.6 (c) is demonstrated. After the protrusions 42 are formed as described above, a ferroelectric material slurry is applied onto the substrate 40 to fill the grooves between the protrusions 42. In this case, it is important to fill the slurry between the protrusions 42 without any gap. Further, the coating thickness of the slurry is made thicker than the height of the protrusion 42 so that the protrusion 42 is buried. As the ferroelectric material, a ferroelectric material having a large piezoelectric constant such as PZT or PLZT is preferably used, and other ferroelectric materials having spontaneous polarization characteristics may be used.

  Thereafter, the slurry is dried using a drying apparatus. In this way, the element body 30 made of a ferroelectric material (precursor) is formed.

  Next, the process shown in FIG. After the element body 30 is formed as described above, the photoresist film 41 is dissolved with an organic solvent to separate the element body 30 from the substrate 40. A groove 30a corresponding to the protrusion 42 is formed in the element body 30 after separation. After separating the element body 30 from the substrate 40, the element body 30 is heated to a temperature of 1200 ° C., for example, and sintered.

  Next, the process shown in FIG. A polarization process is performed on the element body 30 after the sintering process. That is, the upper electrode 43 is formed on the region between the grooves 30a of the element body 30 by sputtering or the like. Similarly, a lower electrode (common electrode) 44 is formed on the entire lower surface of the element body 30 by sputtering or the like. As a material of the upper electrode 43 and the lower electrode 44, for example, Al (aluminum) is used. The thicknesses of the upper electrode 43 and the lower electrode 44 are, for example, 200 nm. When forming the upper electrode 43, the groove 30a is covered using, for example, a metal through mask so that metal does not adhere to the groove 30a.

  Next, the lower electrode 44 is set to the ground potential (0 V), and a voltage of +500 V is applied to the odd-numbered upper electrode 43. Next, the even-numbered upper electrode 43 is set to the ground potential, and a voltage of +500 V is applied to the lower electrode 44. In this way, the polarization process is performed in the opposite direction (anti-parallel direction) with respect to the adjacent ferroelectric blocks across the groove 30a. Alternatively, the lower electrode 44 may be set to the ground potential, and a voltage of +500 V may be applied to the odd-numbered upper electrodes 43, and then a voltage of -500V may be applied to the even-numbered upper electrodes 43.

  Next, the steps shown in FIGS. 7B and 7C will be described. After the polarization process is performed on the element body 30 as described above, the upper electrode 43 and the lower electrode 44 are removed by wet etching using phosphoric acid and nitric acid as etchants as shown in FIG.

  Next, buried electrodes 31a and 31b and collective electrodes 32a and 32b are formed. That is, a predetermined region (a region other than the region where the buried electrodes 31a and 31b and the collective electrodes 32a and 32b are formed) is masked by an organic protective film (not shown) such as a photoresist. Thereafter, a plating seed film (not shown) made of Cu / Cr is formed to a thickness of 300 nm on the entire surface by sputtering or the like. Next, the organic protective film is removed together with the seed film deposited thereon by a solvent.

  Next, Cu (copper) is plated on the seed film to a thickness of, for example, 50 μm by electrolytic plating. As a result, as shown in FIG. 7C, Cu is embedded in the groove 30a to form embedded electrodes 31a and 31b. Further, the collective electrodes 32 a and 32 b are formed by Cu adhering to the side surface of the element body 30. A Cu film 45 is formed on the element body 30 to a thickness of 50 μm.

  Next, as shown in FIG. 7D, the upper surface of the element body 30 is exposed by removing the Cu film 45 on the element body 30 by lapping polishing or the like. Thereafter, the upper surface of the element body 30 is flattened by buffing.

Next, the process shown in FIG. After the embedded electrodes 31a and 31b and the collective electrodes 32a and 32b are formed in the above-described process, the insulating film 33 is formed by depositing alumina (Al ₂ O ₃ ) on the element body 30 by sputtering. The thickness of the insulating film 33 is 5 μm, for example. In this case, a region other than the region where the insulating film 33 is formed is covered with a metal through mask so that the insulating film does not adhere to the collective electrodes 32a and 32b. Thus, the piezoelectric element 20 according to the present embodiment is completed.

  FIG. 8 is a diagram showing the result of simulation calculation of the displacement amount of the piezoelectric element 20 of the present embodiment using the finite element method. However, the element body 30 is made of PZT. The longitudinal length L1 of the element body 30 is 800 μm, the lateral length W1 is 700 μm, and the thickness T1 is 100 μm (see FIG. 3). Further, the vertical length L2 of the embedded electrodes 31a and 31b is 650 μm, the width W2 is 20 μm, the thickness T2 is 80 μm, and the distance L3 between the embedded electrodes 31a and 31b is 60 μm. Furthermore, the drive voltage supplied between the collective electrodes 32a and 32b is 30V.

  As a result, it has become clear that the piezoelectric element of the present embodiment is displaced by a maximum of 42 nm. That is, the piezoelectric element according to this embodiment can displace the slider (magnetic head) in the radial direction (track width direction) of the magnetic disk within a range of ± 42 nm by applying a voltage in the range of ± 30 V. it can.

  In this embodiment, as shown in FIG. 2, the piezoelectric element 20 (microactuator) is disposed between the suspension arm 13 and the slider 12, and the distance between the piezoelectric element 20 and the slider 12 is extremely short. For this reason, the resonance frequency is high, and coupled with the fact that the piezoelectric variation of the piezoelectric element 20 shows a response of microseconds or less, the magnetic head can be positioned at high speed and with high accuracy.

  The displacement amount of the piezoelectric element 20 according to this embodiment is related to the aspect ratio (aspect ratio) of the ferroelectric block between the embedded electrodes 31a and 31b. In the example described above, the aspect ratio of the ferroelectric block (T2 / L3: see FIG. 3) is 1.3 (= 80 μm / 60 μm). However, in order to ensure a sufficient amount of displacement of the magnetic head 17 (slider 12). In addition, the aspect ratio of the ferroelectric block is preferably 1 or more.

  Hereinafter, a magnetic head position control method using the piezoelectric element according to the present embodiment will be described with reference to flowcharts shown in FIGS.

  First, in step S11, the value of the variable n is initialized (n = 1). At this time, the piezoelectric element 20 is not applied with a voltage. In step S12, the electronic circuit unit 15 drives the voice coil motor (VCM) 14 in accordance with a signal from an external device such as a computer, and rotates the suspension arm 13 to move the slider 12 (magnetic head). ) Is moved (loaded) to a predetermined track position on the magnetic disk 11.

  In step S13, the electronic circuit unit 15 reads the magnetic recording signal from the magnetic disk 11 via the magnetic head 17, and determines whether the on-track signal has been confirmed. When the on-track signal is confirmed (in the case of YES), that is, when the magnetic head 17 is at the position of the predetermined track, the process proceeds to step S22 and data is written to or read from the predetermined track. On the other hand, if the on-track signal cannot be confirmed in step S12 (in the case of NO), that is, if the magnetic head is not located at a predetermined track, the process proceeds to step S14.

  In step S <b> 14, the electronic circuit unit 15 applies a positive voltage (positive initial voltage) to the piezoelectric element 20. Here, when a positive voltage is applied to the piezoelectric element 20, the slider 12 (magnetic head 17) moves to the center side of the magnetic disk 11.

  After applying a positive voltage to the piezoelectric element 20 in step S14, in step S15, the magnetic recording signal is read from the magnetic disk 11 by the magnetic head 17, and it is determined whether or not the on-track signal has been confirmed. When the on-track signal can be confirmed (in the case of YES), the process proceeds to step S22, and data is written to or read from a predetermined track. On the other hand, when the on-track signal cannot be confirmed in step S15 (in the case of NO), the process proceeds to step S16.

  In step S16, it is determined whether or not the voltage applied to the piezoelectric element 20 has reached a preset upper limit applied voltage (for example, +30 V). When the applied voltage to the piezoelectric element 20 is smaller than the preset upper limit applied voltage, the process proceeds to step S17 to increase the applied voltage by a predetermined value, and then returns to step S15. In this way, the processes from step S15 to step S17 were performed, and the on-track signal was confirmed by gradually moving the slider 12 (magnetic head 17) toward the center of the magnetic disk 11, and the on-track signal was confirmed. In this case, the process proceeds to step S22, where data is written or read.

  If the on-track signal cannot be confirmed even after performing the processes from step S15 to step S17, that is, if YES in step S16, the process proceeds to step S18.

  In step S18, a negative voltage (negative initial voltage) is applied to the piezoelectric element 20. Thereafter, in step S19, the magnetic recording signal is read from the magnetic disk 11 by the magnetic head 17, and it is determined whether or not the on-track signal is confirmed. When the on-track signal can be confirmed (in the case of YES), the process proceeds to step S22, and data is written to or read from a predetermined track. On the other hand, when the on-track signal cannot be confirmed in step S19 (in the case of NO), the process proceeds to step S20.

  In step S20, it is determined whether or not the applied voltage to the piezoelectric element 20 has reached a preset negative upper limit applied voltage (for example, −30 V). If the applied voltage to the piezoelectric element 20 is smaller than the preset negative upper limit applied voltage, the process proceeds to step S21 to increase the applied voltage by a predetermined value, and then returns to step S19. In this way, the processes from step S19 to step S21 were performed, and the on-track signal was confirmed by gradually moving the slider 12 (magnetic head 17) to the outer peripheral side of the magnetic disk 11, and the on-track signal was confirmed. In this case, the process proceeds to step S22, where data is written or read.

  If the on-track signal cannot be confirmed even after performing the processes from step S19 to step 21, that is, if YES in step S20, the process proceeds to step S23. In step S23, the value of n is examined. If the value of n is 1 in step S23, the process proceeds to step S24. In step S <b> 24, the electronic circuit unit 15 controls the voice coil motor 14 to slightly move the slider 12 (magnetic head 17) to the center side of the magnetic disk 11. Thereafter, the process proceeds to step S25, a value obtained by adding 1 to the value of n is newly set to n, and then the process returns to step S13 to perform the above-described processing.

  If the value of n is 2 in step S23, the process proceeds to step S26. In step S <b> 26, the electronic circuit unit 15 controls the voice coil motor 14 to slightly move the slider 12 (magnetic head 17) to the outer peripheral side of the magnetic disk 11. Thereafter, the process proceeds to step S27, and a value obtained by adding 1 to the value of n is newly set to n. Then, the process returns to step S13, and the above-described processing is performed.

  When the value of n is 3 in step S23, the process proceeds to step S28, and the electronic circuit unit 15 outputs an abnormal signal to an external device such as a computer. The external device displays a message indicating an abnormality of the magnetic recording device, for example, on the display unit by the abnormality signal.

  According to the above magnetic head position control method, the position of the slider 12 (magnetic head 17) is finely adjusted using the piezoelectric element 20 shown in FIGS. Thus, data can be written or read reliably even on a magnetic disk having a high track density.

  Hereinafter, various aspects of the present invention will be collectively described as supplementary notes.

(Appendix 1) An element body made of a piezoelectric film;
A plurality of embedded electrodes embedded in grooves arranged in the width direction of the element body and dividing the element body into a plurality of blocks;
The polarization axes of adjacent blocks are parallel to the thickness direction of the element body, and the polarization directions of the adjacent blocks are opposite to each other, and the adjacent blocks are parallel to the width direction by the embedded electrode. A piezoelectric element, wherein voltages in opposite directions are applied to each other.

  (Additional remark 2) The value of T / L is 1 or more, when the space | interval between the said embedded electrodes is set to L and the length of the said thickness direction of the said embedded electrode is set to T, The additional value 1 characterized by the above-mentioned. Piezoelectric element.

  (Additional remark 3) The said element main body consists of ferroelectrics, The piezoelectric element of Additional remark 1 or 2 characterized by the above-mentioned.

  (Additional remark 4) It has the 1st collective electrode commonly connected to the odd-numbered embedded electrode, and the 2nd collective electrode commonly connected to the even-numbered embedded electrode on the side of the element main body, The piezoelectric element according to any one of supplementary notes 1 to 3.

(Additional remark 5) In the magnetic head assembly which has the slider in which the magnetic head which records or reproduces | regenerates data with respect to a magnetic recording medium was formed, and the piezoelectric element joined to the said slider,
The piezoelectric element is
An element main body made of a piezoelectric film and a plurality of embedded electrodes embedded in grooves arranged in the width direction of the element main body to partition the element main body into a plurality of blocks, and the polarization axes of adjacent blocks are The polarization directions of the adjacent blocks that are parallel to the thickness direction of the element body are opposite to each other, and the adjacent blocks have voltages that are parallel to the width direction and opposite to each other by the embedded electrode. A magnetic head assembly which is applied.

(Appendix 6) Magnetic recording medium;
A slider on which a magnetic head is formed;
A suspension arm that supports the slider;
An actuator that drives the suspension arm to move the slider in a radial direction of the magnetic recording medium;
A piezoelectric element disposed between the slider and the suspension arm and displacing the slider in a radial direction of the magnetic recording medium;
An electronic circuit unit that controls the electromagnetic actuator and the piezoelectric element and performs recording and reproduction of data with respect to the magnetic recording medium via the magnetic head;
The piezoelectric element is
An element main body made of a piezoelectric film and a plurality of embedded electrodes embedded in grooves arranged in the width direction of the element main body to partition the element main body into a plurality of blocks, and the polarization axes of adjacent blocks are The polarization directions of the adjacent blocks that are parallel to the thickness direction of the element body are opposite to each other, and the adjacent blocks have voltages that are parallel to the width direction and opposite to each other by the embedded electrode. A magnetic recording apparatus which is applied.

  (Supplementary Note 7) The electronic circuit unit drives the actuator to place the magnetic head at a predetermined track position of the magnetic recording medium, and then detects a track-on signal from the magnetic recording medium by the magnetic head. The magnetic recording apparatus according to appendix 4, wherein the piezoelectric element is driven.

(Appendix 8) A step of forming a resin film on a substrate;
Patterning the resin film to form stripe-shaped protrusions arranged at regular intervals;
Applying a slurry of a ferroelectric material on the resin film and filling a region between the protrusions with the slurry;
Drying the slurry to form an element body having grooves corresponding to the protrusions;
Dissolving the resin film to separate the element body and the substrate;
Sintering the element body;
Polarizing the element body;
Embedding a conductor material in the groove of the element body,
The method for manufacturing a piezoelectric element characterized in that, in the step of performing the polarization treatment, polarization treatment is performed in parallel to the thickness direction and in opposite directions to adjacent regions among the regions partitioned by the grooves.

FIG. 1 is a plan view showing a configuration of a magnetic recording device (hard disk device) according to an embodiment of the present invention. FIG. 2 is a perspective view showing a suspension arm, a slider attached to the suspension arm, and a piezoelectric element (magnetic head assembly). 3A is a plan view showing the piezoelectric element, and FIG. 3B is a cross-sectional view taken along the line II of FIG. 3A. 4A is a top view schematically showing the piezoelectric element when no voltage is applied, and FIG. 4B is a cross-sectional view thereof. FIG. 5A is a top view schematically showing the piezoelectric element in a state where a voltage is applied, and FIG. 5B is a cross-sectional view thereof. FIG. 6 is a cross-sectional view (part 1) illustrating the method of manufacturing the piezoelectric element according to the embodiment in the order of steps. FIG. 7 is a cross-sectional view (part 2) illustrating the method of manufacturing the piezoelectric element of the embodiment in the order of steps. FIG. 8 is a diagram illustrating a result of simulation calculation of the displacement amount of the piezoelectric element according to the embodiment using a finite element method. FIG. 9 is a flowchart (No. 1) showing the magnetic head position control method using the piezoelectric element according to the embodiment. FIG. 10 is a flowchart (part 2) illustrating the position control method of the magnetic head using the piezoelectric element according to the embodiment.

Explanation of symbols

10: Magnetic recording device,
11 ... Magnetic disk,
12 ... slider,
13 ... Suspension arm,
14 ... Voice coil motor,
15 ... electronic circuit part,
17 ... Magnetic head,
18 ... electrode,
20: Piezoelectric element,
30 ... element body,
30a ... groove,
31a, 31b ... buried electrodes,
32a, 32b ... collective electrodes,
33. Insulating film,
40 ... substrate,
41 ... Photoresist film,
42 ... protrusions,
43 ... Upper electrode,
44 ... lower electrode,
45: Cu film.

Claims (5)

An element body made of a piezoelectric film;
A plurality of embedded electrodes embedded in grooves arranged in the width direction of the element body and dividing the element body into a plurality of blocks;
The polarization axes of adjacent blocks are parallel to the thickness direction of the element body, and the polarization directions of the adjacent blocks are opposite to each other, and the adjacent blocks are parallel to the width direction by the embedded electrode. A piezoelectric element, wherein voltages in opposite directions are applied to each other.   2. The piezoelectric element according to claim 1, wherein a value of T / L is 1 or more, where L is an interval between the embedded electrodes and T is a length of the embedded electrodes in the thickness direction. .   The piezoelectric element according to claim 1, wherein the element body is made of a ferroelectric material. In a magnetic head assembly having a slider on which a magnetic head for recording or reproducing data on a magnetic recording medium is formed, and a piezoelectric element bonded to the slider.
The piezoelectric element is
An element main body made of a piezoelectric film and a plurality of embedded electrodes embedded in grooves arranged in the width direction of the element main body to partition the element main body into a plurality of blocks, and the polarization axes of adjacent blocks are The polarization directions of the adjacent blocks that are parallel to the thickness direction of the element body are opposite to each other, and the adjacent blocks have voltages that are parallel to the width direction and opposite to each other by the embedded electrode. A magnetic head assembly which is applied. A magnetic recording medium;
A slider on which a magnetic head is formed;
A suspension arm that supports the slider;
An actuator that drives the suspension arm to move the slider in a radial direction of the magnetic recording medium;
A piezoelectric element disposed between the slider and the suspension arm and displacing the slider in a radial direction of the magnetic recording medium;
An electronic circuit unit that controls the electromagnetic actuator and the piezoelectric element and performs recording and reproduction of data with respect to the magnetic recording medium via the magnetic head;
The piezoelectric element is
An element main body made of a piezoelectric film and a plurality of embedded electrodes embedded in grooves arranged in the width direction of the element main body to partition the element main body into a plurality of blocks, and the polarization axes of adjacent blocks are The polarization directions of the adjacent blocks which are parallel to the thickness direction of the element body are opposite to each other, and voltages adjacent to the width direction and opposite to each other are applied to the adjacent blocks by the embedded electrode. A magnetic recording apparatus which is applied.

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