JP2011240647A - Piezoelectric material, piezoelectric element, liquid ejection head, and liquid ejector - Google Patents

Abstract

To provide a piezoelectric material, a piezoelectric element, a piezoelectric actuator, a liquid ejecting head, and a liquid ejecting apparatus including a piezoelectric body having good insulation.
A piezoelectric material according to the present invention has a perovskite structure and is a composite oxide containing bismuth, lanthanum, iron, manganese and magnesium, and the molar ratio of manganese to magnesium is 2 or more and 8 or less. is there. In this piezoelectric material, the molar ratio of manganese to the sum of iron, manganese, and magnesium may be 0.02 or more and 0.04 or less.
[Selection figure] None

Description

  The present invention relates to a piezoelectric material, a piezoelectric element, a liquid ejecting head, and a liquid ejecting apparatus.

  The liquid ejecting head is used in, for example, an ink jet printer as a configuration of the liquid ejecting apparatus. In this case, the liquid ejecting head is used for ejecting and ejecting small ink droplets, whereby the ink jet printer can perform printing by attaching the ink to a medium such as paper (Patent Document 1). reference).

  The liquid ejecting head generally includes a piezoelectric element as an actuator that applies pressure to the liquid in order to eject the liquid from the nozzle. As such a piezoelectric element, there is a piezoelectric element having an electromechanical conversion function, for example, a piezoelectric body made of crystallized piezoelectric ceramic or the like and sandwiched between two electrodes. Such a piezoelectric element can be deformed when a voltage is applied by two electrodes, and the actuator can be operated in, for example, a flexural vibration mode using the deformation.

  The piezoelectric material used for such applications preferably has high piezoelectric properties such as electromechanical conversion efficiency, and the properties are superior to other materials. Therefore, lead zirconate titanate (PZT) Research and development of materials of the system has been carried out. However, in recent years, there has been a demand for development of lead-free piezoelectric materials that do not contain harmful lead or suppress the content thereof from the viewpoint of environmental problems.

Among ceramic materials that are theoretically considered to have high piezoelectric properties, for example, there are Bi-based oxides, and at present, BiFeO ₃ (BFO) -based materials are considered as potential candidates.

  However, BFO has a problem that insulation is low and leakage current is large.

JP 2009-283950 A

  The present invention has been made in view of the above-described problems, and according to some aspects of the present invention, a piezoelectric material, a piezoelectric element, a piezoelectric actuator, including a piezoelectric body having good insulation, A liquid ejecting head and a liquid ejecting apparatus can be provided.

(1) The piezoelectric material according to the present invention is
A composite oxide having a perovskite structure and containing bismuth, lanthanum, iron, manganese and magnesium,
The molar ratio of manganese to magnesium is 2 or more and 8 or less.

  According to the present invention, a piezoelectric material with good insulation can be realized.

(2) This piezoelectric material is
The molar ratio of manganese to the sum of iron, manganese, and magnesium may be 0.02 or more and 0.04 or less.

  Thereby, a piezoelectric material with good insulation can be realized.

(3) This piezoelectric material is
The molar ratio of lanthanum to magnesium may be 17 or more and 40 or less.

  Thereby, a piezoelectric material with good insulation can be realized.

(4) The piezoelectric element according to the present invention is
Any one of these piezoelectric materials and an electrode provided on the piezoelectric material are included.

  According to the present invention, it is possible to realize a piezoelectric element including a piezoelectric body with good insulation.

(5) A liquid jet head according to the present invention includes:
This piezoelectric element is provided.

  According to the present invention, it is possible to realize a liquid ejecting head including a piezoelectric body having good insulating properties.

(6) A liquid ejecting apparatus according to the present invention includes:
This liquid ejecting head is provided.

  According to the aspect of the invention, it is possible to realize a liquid ejecting apparatus including a piezoelectric body that has good insulating properties.

The schematic diagram of the cross section of the piezoelectric element 100 which concerns on this embodiment. FIG. 3 is a cross-sectional view schematically illustrating a main part of a liquid jet head according to the present embodiment. FIG. 3 is an exploded perspective view of a liquid ejecting head 600 according to the present embodiment. FIG. 6 is a perspective view schematically showing a liquid ejecting apparatus 700 according to the present embodiment. Example 1 (1001), Example 2 (1002), Example 3 (1003), Example 4 (1004), Example 5 (1005), Example 6 (1006), Comparative Example 1 (2001) and Comparative Example The graph which shows the current-voltage characteristic of the piezoelectric element of Example 2 (2002). The graph showing the electronic state density of BFO which has not carried out atomic substitution using the first principle electronic state calculation based on the density functional method. The graph showing the electronic state density at the time of substituting a part of iron contained in BFO with manganese using the first principle electronic state calculation based on a density functional method. The graph showing the electronic state density at the time of substituting a part of iron contained in BFO with magnesium using the first principle electronic state calculation based on a density functional method.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. Also, not all of the configurations described below are essential constituent requirements of the present invention.

1. Piezoelectric Material The piezoelectric material of the present embodiment is a composite oxide having a perovskite structure and containing bismuth, lanthanum, iron, manganese, and magnesium.

  More specifically, the piezoelectric material is bismuth lanthanum iron manganate and magnesium acid, and can be expressed as, for example, the following formula (I).

_{(Bi v, La w) (} Fe x, Mn y, Mg z) O 3 ··· (I)
This bismuth lanthanum magnesium manganate is a composite oxide represented by ABO ₃ as a general formula, and is classified into a so-called perovskite oxide, and can have a perovskite crystal structure by crystallization. . In the example represented by the above formula (I), the A site of the perovskite structure is composed of bismuth and lanthanum, and the B site of the perovskite structure is composed of iron, manganese, and magnesium. Bismuth lanthanum iron manganate magnesium acid can be crystallized to exhibit a piezoelectric property by taking a perovskite crystal structure.

  When the piezoelectric material of the present embodiment is represented by the type of the above formula (I), v, w, x, y, and z can take values of 0 or more and 1 or less. These values may represent the amount of raw material charged when forming the piezoelectric material, or may represent the composition of the piezoelectric material after formation. Therefore, the neutrality of the charge of the chemical formula may appear to be unsatisfactory in appearance, and in that case, it is understood that the charge value or the degree of crystal defects is indicated.

  The piezoelectric material of this embodiment has a perovskite structure and is a composite oxide containing bismuth, lanthanum, iron, manganese, and magnesium, and the molar ratio of manganese to magnesium is 2 or more and 8 or less. That is, when the piezoelectric material of this embodiment is represented by the type of the above formula (I), 2 ≦ y / z ≦ 8.

  In the piezoelectric material of this embodiment, the molar ratio of manganese to magnesium is in this range, so that the insulation is good.

  In the piezoelectric material of the present embodiment, the molar ratio of manganese to the sum of iron, manganese and magnesium in the composite oxide having a perovskite structure and containing bismuth, lanthanum, iron, manganese and magnesium is 0.02 or more and 0. .04 or less. That is, when the piezoelectric material of the present embodiment is represented by the type of the above formula (I), 0.02 ≦ y / (x + y + z) ≦ 0.04 can be satisfied. If it does in this way, the insulation of a piezoelectric material will become favorable.

  In the piezoelectric material of this embodiment, the molar ratio of lanthanum to magnesium in the composite oxide having a perovskite structure and including bismuth, lanthanum, iron, manganese, and magnesium may be 17 or more and 40 or less. More preferably, the ratio of the number of moles of lanthanum to the number of moles of magnesium may be 19 or more and 38 or less. That is, when the piezoelectric material of the present embodiment is represented by the type of the above formula (I), 17 ≦ w / z ≦ 40 can be satisfied. More preferably, it can be set as 19 <= w / z <= 38. If it does in this way, the insulation of a piezoelectric material will become favorable.

2. Piezoelectric Element and Piezoelectric Actuator FIG. 1 is a schematic cross-sectional view of a piezoelectric element 100 according to this embodiment.

  The piezoelectric element 100 according to this embodiment includes a first conductive layer 10, a second conductive layer 20, and a piezoelectric body 30.

2.1. First Conductive Layer The first conductive layer 10 is formed, for example, above the substrate 1. The substrate 1 can be, for example, a flat plate formed of a conductor, a semiconductor, or an insulator. The substrate 1 may be a single layer or a structure in which a plurality of layers are stacked. Further, the inner structure of the substrate 1 is not limited as long as the upper surface is planar. For example, the substrate 1 may have a structure in which a space or the like is formed. Further, for example, in the case where a pressure chamber or the like is formed below the substrate 1 as in a liquid jet head described later, a plurality of configurations formed below the substrate 1 are combined into one substrate 1. May be considered.

  The substrate 1 may be an elastic member (diaphragm) that has flexibility and can be deformed (bent) by the operation of the piezoelectric body 30. In this case, the piezoelectric element 100 is a piezoelectric actuator 102 including an elastic member (vibrating plate), the first conductive layer 20, the piezoelectric body 30, and the second conductive layer 20. Here, that the substrate 1 has flexibility indicates that the substrate 1 can bend. When the substrate 1 is an elastic member (vibrating plate), the deflection of the substrate 1 is such that when the piezoelectric actuator 102 is used for a liquid ejecting head, the volume of the pressure chamber can be changed to the same level as the volume of liquid to be ejected. If there is enough.

  When the substrate 1 is an elastic member (diaphragm), examples of the material of the substrate 1 include inorganic oxides such as zirconium oxide (ZrO2), silicon nitride, and silicon oxide, and alloys such as stainless steel. it can. Among these, zirconium oxide is particularly preferable as a material for the elastic member (diaphragm) in terms of chemical stability and rigidity. Also in this case, the substrate 1 may have a laminated structure of two or more kinds of the exemplified substances.

  In the present embodiment, the case where the substrate 1 is an elastic member (diaphragm) and is formed of zirconium oxide will be exemplified below. Accordingly, the piezoelectric element 100 is substantially the same as the piezoelectric actuator 102 having an elastic member (vibrating plate) that has flexibility and can be deformed (bent) by the operation of the piezoelectric body 30. In the following description, the piezoelectric element 100 and the piezoelectric actuator 102 can be read each other.

  Although the shape of the 1st conductive layer 10 is not limited as long as it can oppose the 2nd conductive layer 20, in this embodiment, since the piezoelectric material 30 is formed in a thin film form, a layered form or a thin film form is preferable. The thickness of the 1st conductive layer 10 can be 50 nm or more and 300 nm or less, for example. Also, the planar shape of the first conductive layer 10 is not particularly limited as long as the piezoelectric body 30 can be disposed between the two conductive layers 20 when the second conductive layer 20 is disposed to face the first conductive layer 10. , Rectangular, circular, etc.

  One function of the first conductive layer 10 is to form a pair with the second conductive layer 20 to apply a voltage to the piezoelectric body 30 (for example, a lower portion formed below the piezoelectric body 30). Electrode). The first conductive layer 10 may have a function of controlling the crystal orientation when the piezoelectric body 30 is crystallized.

  Examples of the material of the first conductive layer 10 include various metals such as nickel, iridium, and platinum, conductive oxides thereof (for example, iridium oxide), strontium and ruthenium composite oxide (SrRuOx: SRO), and lanthanum. And a composite oxide of nickel and nickel (LaNiOx: LNO). The first conductive layer 10 may have a single layer structure of the exemplified materials, or may have a structure in which a plurality of materials are stacked.

2.2. Second Conductive Layer The second conductive layer 20 is disposed to face the first conductive layer 10. The entire second conductive layer 20 may face the first conductive layer 10, or a part thereof may face the first conductive layer 10. The shape of the second conductive layer 20 is not limited as long as the second conductive layer 20 can face the first conductive layer 10. However, in the present embodiment, since the piezoelectric body 30 is formed in a thin film shape, a layer shape or a thin film shape is preferable. The thickness of the 2nd conductive layer 20 can be 50 nm or more and 300 nm or less, for example. Further, the planar shape of the second conductive layer 20 is not particularly limited as long as the piezoelectric body 30 can be disposed between the two when the first conductive layer 10 is opposed to the first conductive layer 10. , Rectangular, circular, etc.

  One of the functions of the second conductive layer 20 is to serve as one electrode for applying a voltage to the piezoelectric body 30 (for example, an upper electrode formed on the piezoelectric body 30). The second conductive layer 20 may have a function of controlling the crystal orientation when the piezoelectric body 30 is crystallized. The material of the second conductive layer 20 can be the same as that of the first conductive layer 10 described above.

  FIG. 1 shows an example in which the first conductive layer 10 is formed to be larger than the second conductive layer 20 in a plan view. However, the second conductive layer 20 is formed to be larger than the first conductive layer 10 in a plan view. May be. In this case, the second conductive layer 20 may be formed on the side surface of the piezoelectric body 30, and the second conductive layer 20 can also have a function of protecting the piezoelectric body 30 from moisture, hydrogen, and the like.

2.3. Piezoelectric Body The piezoelectric body 30 is disposed between the first conductive layer 10 and the second conductive layer 20. The piezoelectric body 30 may be in contact with at least one of the first conductive layer 10 and the second conductive layer 20. In the example of FIG. 1, the piezoelectric body 30 is provided in contact with the first conductive layer 20 and the second conductive layer 20.

  The piezoelectric body 30 may be formed by a thin film method. Examples of the thin film method include sputtering, vapor deposition, MOCVD (Metal-Organic Chemical Deposition), MOD (Metal-Organic Deposition), PLD (Pulsed Laser Deposition), and laser ablation. And at least one of sol-gel methods. Further, the piezoelectric body 30 of the present embodiment may be formed in a bulk state.

  The thickness of the piezoelectric body 30 is not particularly limited, and can be, for example, 100 nm or more and 3000 nm or less. In the case where the piezoelectric body 30 having a large thickness is formed by the thin film method, for example, in a method of depositing a material such as a sputtering method, a vapor deposition method, or an MOCVD method, the piezoelectric material 30 can be formed by increasing the deposition time. Further, for example, in a method of coating and baking such as MOD method or sol-gel method, it can be formed by repeatedly stacking the method. Furthermore, when laminating, each layer may be laminated using a different thin film method. If the thickness of the piezoelectric body 30 is out of this range, the withstand voltage may be insufficient, or sufficient deformation (electromechanical conversion) may not be obtained.

  The piezoelectric body 30 of the present embodiment is made of the piezoelectric material described in the section “1. Piezoelectric material”. In this way, the insulation property of the piezoelectric element 100 is improved.

  The piezoelectric element 100 of this embodiment can be used for a wide range of applications. Applications of the piezoelectric actuator 102 include, for example, a liquid ejecting apparatus such as a liquid ejecting head and an ink jet printer. Applications of the piezoelectric element 100 include various sensors such as a gyro sensor and an acceleration sensor, a tuning fork vibrator, and the like. It can be suitably used for ultrasonic devices such as timing devices and ultrasonic motors.

3. Piezoelectric Material and Piezoelectric Element Manufacturing Method The piezoelectric material of the present embodiment and the piezoelectric element 100 using the same can be manufactured as follows, for example.

  First, the substrate 1 is prepared, and the first conductive layer 10 is formed on the substrate 1. The first conductive layer 10 can be formed by, for example, a sputtering method, a plating method, a vacuum evaporation method, or the like. The first conductive layer 10 can be patterned as necessary.

  Next, the piezoelectric body 30 made of the piezoelectric material of the present embodiment is formed on the first conductive layer 10. As described above, the piezoelectric body 30 is formed by, for example, sputtering, vapor deposition, MOCVD (Metal-Organic Chemical Deposition), MOD (Metal-Organic Deposition), PLD (Pulsed Laser Deposition), or laser ablation. It can be formed by at least one of a mist film forming method and a sol-gel method, or a combination of these methods. The crystallization of the piezoelectric body 30 can be performed, for example, at 500 ° C. or higher and 800 ° C. or lower. Thereby, the piezoelectric body 30 can be crystallized. Crystallization may be performed after the piezoelectric body 30 is patterned. Then, if necessary, the above operation can be repeated a plurality of times to obtain the piezoelectric body 30 having a desired thickness.

  Next, the second conductive layer 20 is formed on the piezoelectric body 30. The second conductive layer 20 can be formed by, for example, a sputtering method, a plating method, a vacuum evaporation method, or the like. Then, the second conductive layer 20 and the piezoelectric body 30 are patterned into a desired shape to form a piezoelectric element. The second conductive layer 20 and the piezoelectric body 30 can be simultaneously patterned as necessary. Through the processes exemplified above, the piezoelectric material of the present embodiment and the piezoelectric element 100 using the same can be manufactured.

4). Liquid Ejecting Head Next, as an example of the application of the piezoelectric element (piezoelectric actuator) according to the present embodiment, a liquid ejecting head 600 having these will be described with reference to the drawings. FIG. 2 is a cross-sectional view schematically showing the main part of the liquid jet head 600 according to the present embodiment. FIG. 3 is an exploded perspective view of the liquid ejecting head 600 according to the present embodiment, which is shown upside down from a state in which it is normally used.

  The liquid ejecting head 600 can include the above-described piezoelectric element (piezoelectric actuator). In the following, a liquid ejecting head 600 in which the piezoelectric element 100 is formed on the substrate 1 (the structure including the vibration plate 1 a on the upper portion) and the piezoelectric element 100 and the vibration plate 1 a constitute the piezoelectric actuator 102 will be exemplified. I will explain.

  As shown in FIGS. 2 and 3, the liquid ejecting head 600 includes a nozzle plate 610 having nozzle holes 612, a pressure chamber substrate 620 for forming the pressure chamber 622, and the piezoelectric element 100. Furthermore, the liquid ejecting head 600 can include a housing 630 as illustrated in FIG. 3. In FIG. 3, the piezoelectric element 100 is illustrated in a simplified manner.

  As shown in FIGS. 2 and 3, the nozzle plate 610 has nozzle holes 612. Ink can be ejected from the nozzle holes 612. In the nozzle plate 610, for example, a number of nozzle holes 612 are provided in a line. Examples of the material of the nozzle plate 620 include silicon and stainless steel (SUS).

  The pressure chamber substrate 620 is provided on the nozzle plate 610 (lower in the example of FIG. 3). Examples of the material of the pressure chamber substrate 620 include silicon. As the pressure chamber substrate 620 divides the space between the nozzle plate 610 and the diaphragm 1a, as shown in FIG. 3, a reservoir (liquid reservoir) 624, a supply port 626 communicating with the reservoir 624, and a supply A pressure chamber 622 communicating with the port 626 is provided. In this example, the reservoir 624, the supply port 626, and the pressure chamber 622 will be described separately, but these are all liquid flow paths, and any such flow paths may be designed. Absent. Further, for example, the supply port 626 has a shape in which a part of the flow path is narrowed in the illustrated example, but can be arbitrarily formed according to the design, and is not necessarily an essential configuration. The reservoir 624, the supply port 626, and the pressure chamber 622 are partitioned by the nozzle plate 610, the pressure chamber substrate 620, and the vibration plate 1a. The reservoir 624 can temporarily store ink supplied from the outside (for example, an ink cartridge) through a through hole 628 provided in the vibration plate 1a. The ink in the reservoir 624 can be supplied to the pressure chamber 622 via the supply port 626. The volume of the pressure chamber 622 changes due to the deformation of the diaphragm 1a. The pressure chamber 622 communicates with the nozzle hole 612, and ink or the like is ejected from the nozzle hole 612 when the volume of the pressure chamber 622 changes.

  The piezoelectric element 100 is provided on the pressure chamber substrate 620 (lower in the example of FIG. 3). The piezoelectric element 100 is electrically connected to a piezoelectric element driving circuit (not shown), and can operate (vibrate or deform) based on a signal from the piezoelectric element driving circuit. The diaphragm 1 a can be deformed by the operation of the piezoelectric body 30 to change the internal pressure of the pressure chamber 622 as appropriate.

  As shown in FIG. 3, the housing 630 can accommodate the nozzle plate 610, the pressure chamber substrate 620, and the piezoelectric element 100. Examples of the material of the housing 630 include resin and metal.

  The liquid ejecting head 600 includes the above-described piezoelectric element 100 that is excellent in at least insulation. Therefore, it is possible to realize a liquid jet head including a piezoelectric body with good insulation.

  Here, the case where the liquid ejecting head 600 is an ink jet recording head has been described. However, the liquid ejecting head of the present embodiment is, for example, an electrode material ejecting head used for electrode formation such as a color material ejecting head, an organic EL display, and an FED (surface emitting display) used for manufacturing a color filter such as a liquid crystal display. It can also be used as a bio-organic matter ejecting head used for biochip manufacturing.

5). Next, a liquid ejecting apparatus 700 according to this embodiment will be described with reference to the drawings. FIG. 4 is a perspective view schematically showing the liquid ejecting apparatus 700 according to this embodiment. The liquid ejecting apparatus 700 includes the liquid ejecting head 600 described above. Hereinafter, a case where the liquid ejecting apparatus 700 is an ink jet printer having the above-described liquid ejecting head 600 will be described.

  As illustrated in FIG. 4, the liquid ejecting apparatus 700 includes a head unit 730, a driving unit 710, and a control unit 760. The liquid ejecting apparatus 700 further includes an apparatus main body 720, a paper feeding unit 750, a tray 721 on which the recording paper P is installed, a discharge port 722 for discharging the recording paper P, and an apparatus main body 720. And an operation panel 770 disposed on the upper surface.

  The head unit 730 includes an ink jet recording head (hereinafter, also simply referred to as “head”) configured from the liquid ejecting head 600 described above. The head unit 730 further includes an ink cartridge 731 that supplies ink to the head, and a transport unit (carriage) 732 on which the head and the ink cartridge 731 are mounted.

  The drive unit 710 can reciprocate the head unit 730. The drive unit 710 includes a carriage motor 741 serving as a drive source for the head unit 730, and a reciprocating mechanism 742 that receives the rotation of the carriage motor 741 and reciprocates the head unit 730.

  The reciprocating mechanism 742 includes a carriage guide shaft 744 supported at both ends by a frame (not shown), and a timing belt 743 extending in parallel with the carriage guide shaft 744. The carriage guide shaft 744 supports the carriage 732 while allowing the carriage 732 to freely reciprocate. Further, the carriage 732 is fixed to a part of the timing belt 743. When the timing belt 743 is caused to travel by the operation of the carriage motor 741, it is guided to the carriage guide shaft 744 and the head unit 730 reciprocates. During this reciprocation, ink is appropriately discharged from the head, and printing on the recording paper P is performed.

  In the present embodiment, an example of a liquid ejecting apparatus in which printing is performed while both the liquid ejecting head 600 and the recording paper P move is shown, but the liquid ejecting apparatus of the present invention includes the liquid ejecting head 600 and the recording. Any mechanism may be used as long as the paper P is printed on the recording paper P by changing its position relative to each other. Further, in the present embodiment, an example is shown in which printing is performed on the recording paper P. However, the recording medium that can be printed by the liquid ejecting apparatus of the present invention is not limited to paper, and may be cloth, film, A wide range of media such as metal can be used, and the configuration can be changed as appropriate.

  The control unit 760 can control the head unit 730, the driving unit 710, and the paper feeding unit 750.

  The paper feeding unit 750 can feed the recording paper P from the tray 721 to the head unit 730 side. The paper feed unit 750 includes a paper feed motor 751 serving as a drive source thereof, and a paper feed roller 752 that rotates by the operation of the paper feed motor 751. The paper feed roller 752 includes a driven roller 752a and a drive roller 752b that are vertically opposed to each other with the feeding path of the recording paper P interposed therebetween. The drive roller 752b is connected to the paper feed motor 751. When the paper supply unit 750 is driven by the control unit 760, the recording paper P is sent so as to pass below the head unit 730.

  The head unit 730, the driving unit 710, the control unit 760, and the paper feeding unit 750 are provided inside the apparatus main body 720.

  The liquid ejecting apparatus 700 includes the piezoelectric element 100 excellent in at least the above-described insulation. Therefore, it is possible to realize a liquid ejecting apparatus including a piezoelectric body that has good insulation.

  Note that the liquid ejecting apparatus 700 exemplified above includes one liquid ejecting head 600, and the liquid ejecting head 600 can perform printing on a recording medium. However, the liquid ejecting apparatus 700 includes a plurality of liquid ejecting heads. May be. When the liquid ejecting apparatus includes a plurality of liquid ejecting heads, the plurality of liquid ejecting heads may be independently operated as described above, or the plurality of liquid ejecting heads may be connected to each other to It may be a gathered head. An example of such a set of heads is a line-type head in which nozzle holes of a plurality of heads have a uniform interval as a whole.

  As described above, the liquid ejecting apparatus 700 as an ink jet printer has been described as an example of the liquid ejecting apparatus according to the present invention. However, the liquid ejecting apparatus according to the present invention can be used industrially. As the liquid (liquid material) discharged in this case, various functional materials adjusted to an appropriate viscosity with a solvent or a dispersion medium can be used. In addition to the exemplified image recording apparatus such as a printer, the liquid ejecting apparatus of the present invention includes a color material ejecting apparatus, an organic EL display, an FED (surface emitting display), and an electrophoretic display used for manufacturing a color filter such as a liquid crystal display. The present invention can also be suitably used as a liquid material ejecting apparatus used for forming electrodes such as electrodes and color filters, and a bioorganic material ejecting apparatus used for biochip manufacturing.

6). Examples and Comparative Examples Examples and Comparative Examples are shown below to describe the present invention more specifically. In addition, this invention is not limited at all by the following examples.

6.1. Production of Piezoelectric Element The piezoelectric elements of Examples 1 to 6 and Comparative Examples 1 to 2 were produced as follows.

The substrate was produced by the following process. First, a silicon oxide (SiO ₂ ) film having a thickness of 1000 nm was formed on the surface of a silicon (Si) substrate by thermal oxidation. Next, a 400 nm-thickness zirconium oxide (ZrO ₂ ) film was formed on the SiO ₂ film by DC sputtering and thermal oxidation. Next, a 20 nm thick titanium (Ti) film and a 130 nm thick platinum (Pt) lower electrode layer (first conductive layer 20) were formed on the ZrO ₂ film by DC sputtering.

  The piezoelectric bodies 30 of each example and each comparative example were each produced by a chemical solution method. On the first conductive layer 10, a precursor solution of bismuth lanthanum iron manganate and magnesium oxide was applied by spin coating. This precursor solution had a different composition for each example and comparative example. The rotation speed in spin coating was 1500 rpm.

  Next, the applied precursor film was dried in air at 150 ° C. for 2 minutes to remove the solvent. Subsequently, it heat-processed for 4 minutes at 350 degreeC in air | atmosphere, and removed the organic component in a precursor film | membrane (degreasing | defatting). For each of the Examples and Comparative Examples, the combination of the precursor solution, drying, and degreasing was repeated twice. Subsequently, it introduce | transduced into the baking furnace (Rapid Thermal Annealing (RTA)), and baked at 650 degreeC for 2 minute (s), performing 0.5 L / min nitrogen flow.

  Further, for each of the examples and comparative examples, each of the precursor solution coating, drying, and degreasing groups was repeated three times and the firing was repeated twice, and then a nitrogen flow of 0.5 L / min was performed at 650 ° C. For 5 minutes. Thereby, a piezoelectric body 30 having a thickness of 500 nm was obtained.

  Further, a 100 nm-thick Pt film was formed thereon as the second conductive layer 20 by DC sputtering. Thereafter, the second conductive layer 20 was baked at 650 ° C. for 5 minutes while introducing a 0.5 L / min nitrogen flow into the RTA furnace, and the piezoelectric elements of the examples and comparative examples were respectively Produced.

  In each example and each comparative example, as a precursor solution in the chemical solution method, a solution using octane, xylene, and n-butanol as solvents for organic acid salts of bismuth, lanthanum, iron, manganese, and magnesium was used. . The composition of the precursor solution of bismuth lanthanum manganate manganate is shown in Table 1 as the concentration of the element contained in the raw material solution for each Example and each Comparative Example. %))). Moreover, about each Example and each comparative example, the coefficient ratio represented using the coefficient v, w, x, y, z at the time of describing with the type | formula of said Formula (I) in Table 1 was described.

6.2. Evaluation of Piezoelectric Elements The piezoelectric elements of the examples and comparative examples were evaluated by measuring current-voltage characteristics. A given voltage is applied between the first conductive layer and the second conductive layer of the piezoelectric element, and a leakage current flowing between the first conductive layer and the second conductive layer when a given voltage is applied is measured. The current-voltage characteristics were evaluated by plotting the horizontal axis as the applied voltage and the vertical axis as the leakage current density.

5 shows Example 1 (1001), Example 2 (1002), Example 3 (1003), Example 4 (1004), Example 5 (1005), Example 6 (1006), and Comparative Example 1 ( 2001) and a graph showing current-voltage characteristics of piezoelectric elements of Comparative Example 2 (2002). The horizontal axis represents the applied voltage [V] indicated by a linear scale, and the vertical axis represents the leakage current density [A / cm ² ] indicated by a log scale.

  As shown in FIG. 5, in the range where the absolute value of the applied voltage is 20 V or more and 30 V or less, compared to the piezoelectric element of Comparative Example (2001) not containing Mg, Example 1 (1001) and Example 2 ( 1002), Example 3 (1003), Example 4 (1004), Example 5 (1005), and Example 6 (1006) were found to have reduced leakage current. On the other hand, it was found that the leakage current of the piezoelectric element of Comparative Example 2 (2002) was increased as compared with the piezoelectric element of Comparative Example 1 (2001).

  Thus, the piezoelectric elements of Example 1 (1001), Example 2 (1002), Example 3 (1003), Example 4 (1004), Example 5 (1005) and Example 6 (1006) are: It was found that the piezoelectric elements of the comparative example 1 (2001) and the comparative example 2 (2002) have better insulating properties.

  The evaluation of these experimental results is summarized in Table 2. In the evaluation on the negative side and the positive side, in the range where the absolute value of the applied voltage is 20 V or more and 30 V or less, “◯” indicates that the leakage current is smaller than that of the piezoelectric element of Comparative Example 1, and the leakage current is the piezoelectric of Comparative Example 1. An element equivalent to the element was represented by “Δ”, and an element having a leakage current larger than that of the piezoelectric element of Comparative Example 1 was represented by “x”. Comprehensive evaluation is based on the evaluation of negative side and positive side, and “O” indicates that the insulation is better than the piezoelectric element of Comparative Example 1, and the insulation is equivalent to the piezoelectric element of Comparative Example Is indicated by “Δ”, and “×” indicates that the insulation property is poorer than that of the piezoelectric element of Comparative Example 1.

  As shown in Table 2, it was found that when the piezoelectric material is represented by the type of the above formula (I), the insulation property of the piezoelectric material is good in the range of 2 ≦ y / z ≦ 8.

6.3. Consideration about Examples and Comparative Examples In bismuth lanthanum manganate manganate, magnesium is contained in the B site of the perovskite type structure. From the above examples and comparative examples, in order to improve insulation, It can be seen that the composition ratio of the B site is important.

  In the following, using the first-principles electronic state calculation based on the density functional method, the electronic state density in the case of atomic substitution of iron at the B site was examined. FIG. 6 shows the electronic state density of BFO without atomic substitution. FIG. 7 is a graph showing the density of electronic states when a part of iron contained in the B site is substituted with manganese, and FIG. 8 is a graph showing the density of electronic states when a part of iron contained in the B site is substituted with magnesium. . In both cases, the horizontal axis represents energy [eV], and the vertical axis represents density of states (DOS) [/ eV].

  From FIG. 6, it can be seen that pure BFO without atomic substitution at the B site has an open band gap and is an insulator. At this time, the iron at the B site is in a trivalent state.

  From FIG. 7, when a part of iron contained in BFO is replaced with manganese, a state density peak corresponding to one electron occupied in the band gap appears. Therefore, it can be seen that manganese functions as a tetravalent (n-type) dopant. Further, from FIG. 8, when a part of iron contained in BFO is replaced with magnesium, a hole for one electron is vacated in the valence band. Therefore, it turns out that magnesium is functioning as a bivalent (p-type) dopant.

  Therefore, it is considered that a part of iron contained in BFO is replaced with n-type manganese and p-type magnesium, so that a valence balance is obtained and insulation is improved. Accordingly, also in this material system, the ratio of the number of moles of manganese to the number of moles of magnesium (y / z) is considered to be an important parameter for improving the insulation.

  The embodiments and modified embodiments described above can be arbitrarily combined with a plurality of forms. Thereby, combined embodiment can have an effect which each embodiment has, or a synergistic effect.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 Board | substrate, 1a Diaphragm, 10 1st conductive layer, 20 2nd conductive layer, 30 Piezoelectric body, 100 Piezoelectric element, 102 Piezoelectric actuator, 600 Liquid ejecting head, 610 Nozzle plate, 612 Nozzle hole, 620 Pressure chamber board, 622 Pressure chamber, 624 reservoir, 626 supply port, 630 casing, 700 liquid ejection device, 710 drive unit, 720 device main body, 721 tray, 722 discharge port, 730 head unit, 731 ink cartridge, 732 carriage, 741 carriage motor, 742 Reciprocating mechanism, 743 timing belt, 744 carriage guide shaft, 750 paper feed unit, 751 paper feed motor, 752 paper feed roller, 752a driven roller, 752b drive roller, 760 control unit, 770 operation panel, 1001 1, 1002 Example 2, 1003 Example 3, 1004 Example 4, 1005 Example 5, 1006 Example 6, 2001 Comparative Example 1, 2002 Comparative Example 2

Claims (6)

A composite oxide having a perovskite structure and containing bismuth, lanthanum, iron, manganese and magnesium,
A piezoelectric material having a molar ratio of manganese to magnesium of 2 or more and 8 or less. The piezoelectric material according to claim 1,
The piezoelectric material whose molar ratio of manganese with respect to the sum of iron, manganese, and magnesium is 0.02 or more and 0.04 or less. The piezoelectric material according to any one of claims 1 and 2,
A piezoelectric material having a molar ratio of lanthanum to magnesium of 17 or more and 40 or less.   A piezoelectric element comprising the piezoelectric material according to claim 1 and an electrode provided on the piezoelectric material.   A liquid ejecting head comprising the piezoelectric element according to claim 4.   A liquid ejecting apparatus comprising the liquid ejecting head according to claim 5.