Piezoelectric element, ink jet head, angular velocity sensor, and ink jet recording apparatus
In a piezoelectric element, a cubic or tetragonal orientation control layer ( 15 ) is provided on a first electrode layer ( 14 ), and formed on the orientation control layer ( 15 ) is a piezoelectric layer ( 16 ) having a rhombohedral or tetragonal crystalline structure and made of lead zirconate titanate to which a Pb-containing complex perovskite compound expressed by the chemical formula Pb(A a B b )O 3 has been added in an amount that is from 1 mol % to 50 mol %. The piezoelectric layer ( 16 ) is formed so that the crystal grains thereof become columnar grains which extend in the thickness direction of the piezoelectric layer ( 16 ) and in which the ratio of the average cross-sectional diameter to the length is from 1/50 to 1/14.
1. A piezoelectric element comprising: a first electrode layer; an orientation control layer provided on the first electrode layer; a piezoelectric layer provided on the orientation control layer; and a second electrode layer provided on the piezoelectric layer,
wherein the orientation control layer is made of a cubic or tetragonal perovskite oxide;
the piezoelectric layer has a rhombohedral or tetragonal crystalline structure and is made of lead zirconate titanate to which a Pb-containing complex perovskite compound whose chemical formula is expressed as Pb(A a B b )O 3 has been added in an amount that is from 1 mol % to 50 mol %; and
crystal grains of the piezoelectric layer are columnar grains which extend thickness-wise in the piezoelectric layer and in which the ratio of the average cross-sectional diameter of the grains to the grain length is from 1/50 to 1/14.
2. The piezoelectric element of claim 1 , wherein the orientation control layer is preferentially oriented along a (100) or (001) plane, and
the piezoelectric layer is preferentially oriented along a (001) plane.
3. The piezoelectric element of claim 2 , wherein the first electrode layer is made of a noble metal containing titanium or titanium oxide.
4. The piezoelectric element of claim 3 , wherein the noble metal of the first electrode layer is at least one element selected from the group consisting of platinum, iridium, palladium and ruthenium, and
the content of the titanium or titanium oxide which is contained in the noble metal is greater than zero and less than or equal to 30 mol %.
5. The piezoelectric element of claim 3 , wherein titanium or titanium oxide existing at a surface of the first electrode layer that is closer to the orientation control layer protrudes less than 2 nm from the surface.
6. The piezoelectric element of claim 2 , wherein the first electrode is made of a noble metal containing at least one substance selected from the group consisting of Mn, Fe, Co, Ni, Mg, Ca, Sr, Ba, Al, and oxides of these elements.
7. The piezoelectric element of claim 6 , wherein the noble metal of the first electrode layer is at least one element selected from the group consisting of platinum, iridium, palladium and ruthenium, and
the content of the substance which is contained in the noble metal is greater than zero and less than or equal to 30 mol %.
8. The piezoelectric element of claim 6 , wherein the substance contained in the noble metal of the first electrode layer and existing at a surface of the first electrode layer that is closer to the orientation control layer protrudes less than 2 nm from the surface.
9. The piezoelectric element of claim 1 , wherein the orientation control layer and the piezoelectric layer are both preferentially oriented along a (111) plane.
10. The piezoelectric element of claim 3 , wherein the degree of (111) orientation of the orientation control layer is 50% or more.
11. The piezoelectric element of claim 1 , wherein in the chemical formula of the Pb-containing complex perovskite compound, the element A is at least one element selected from the group consisting of Mg, Mn, Ni, Co, Zn, and Cd, and the element B is Nb; and
in the chemical formula, the value of a is ⅓ and the value of b is ⅔.
12. The piezoelectric element of claim 1 , wherein in the chemical formula of the Pb-containing complex perovskite compound, the element A is at least one element selected from the group consisting of Mg, Mn, and Ni, and the element B is Ta or Sb; and
in the chemical formula, the value of a is ⅓ and the value of b is ⅔.
13. The piezoelectric element of claim 1 , wherein in the chemical formula of the Pb-containing complex perovskite compound, the element A is at least one element selected from the group consisting of Fe, Cr, In, Y, Sb, and Mn, and the element B is Nb; and
in the chemical formula, the value of a is ½ and the value of b is ½.
14. The piezoelectric element of claim 1 , wherein in the chemical formula of the Pb-containing complex perovskite compound, the element A is at least one element selected from the group consisting of Fe, Cr, and Mn, and the element B is Ta; and
in the chemical formula, the value of a is ½ and the value of b is ½.
15. The piezoelectric element of claim 1 , wherein in the chemical formula of the Pb-containing complex perovskite compound, the element A is at least one element selected from the group consisting of Mn, Ni, Co, Mg, and Zn, and the element B is Te or W; and
in the chemical formula, the value of a is ½ and the value of b is ½.
16. The piezoelectric element of claim 1 , wherein the orientation control layer is made of lead lanthanum zirconate titanate whose zirconium content is equal to or greater than zero and less than or equal to 20 mol % and whose lead content is in excess of the stoichiometric composition by an amount greater than zero and less than or equal to 30 mol %, or made of the lead lanthanum zirconate titanate to which at least one of magnesium and manganese is added.
17. The piezoelectric element of claim 16 , wherein the lanthanum content of the lead lanthanum zirconate titanate in the orientation control layer is greater than zero and less than or equal to 25 mol %.
18. The piezoelectric element of claim 16 , wherein when at least one of magnesium and manganese is added to the lead lanthanum zirconate titanate in the orientation control layer, the total amount thereof to be added is greater than zero and less than or equal to 10 mol %.
19. The piezoelectric element of claim 1 , wherein the first electrode layer is formed on a substrate, and
an adhesive layer for improving adhesion between the substrate and the first electrode layer is provided between the substrate and the first electrode layer.
20. An ink jet head, comprising: a piezoelectric element in which a first electrode layer, an orientation control layer, a piezoelectric layer and a second electrode layer are layered in this order; a vibration layer provided on one surface of the piezoelectric element that is closer to the second electrode layer; and a pressure chamber member bonded to one surface of the vibration layer that is away from the piezoelectric element and including a pressure chamber for storing ink therein, in which the vibration layer is displaced in a thickness direction by a piezoelectric effect of the piezoelectric layer of the piezoelectric element so as to discharge the ink out of the pressure chamber,
wherein the orientation control layer of the piezoelectric element is made of a cubic or tetragonal perovskite oxide;
the piezoelectric layer has a rhombohedral or tetragonal crystalline structure and is made of lead zirconate titanate to which a Pb-containing complex perovskite compound whose chemical formula is expressed as Pb(A a B b )O 3 has been added in an amount that is from 1 mol % to 50 mol %; and
crystal grains of the piezoelectric layer are columnar grains which extend thickness-wise in the piezoelectric layer and in which the ratio of the average cross-sectional diameter of the grains to the grain length is from 1/50 to 1/14.
21. An ink jet head, comprising: a piezoelectric element in which a first electrode layer, an orientation control layer, a piezoelectric layer and a second electrode layer are layered in this order; a vibration layer provided on one surface of the piezoelectric element that is closer to the first electrode layer; and a pressure chamber member bonded to one surface of the vibration layer that is away from the piezoelectric element and including a pressure chamber for storing ink therein, in which the vibration layer is displaced in a thickness direction by a piezoelectric effect of the piezoelectric layer of the piezoelectric element so as to discharge the ink out of the pressure chamber,
wherein the orientation control layer of the piezoelectric element is made of a cubic or tetragonal perovskite oxide;
the piezoelectric layer has a rhombohedral or tetragonal crystalline structure and is made of lead zirconate titanate to which a Pb-containing complex perovskite compound whose chemical formula is expressed as Pb(A a B b )O 3 has been added in an amount that is from 1 mol % to 50 mol %; and
crystal grains of the piezoelectric layer are columnar grains which extend thickness-wise in the piezoelectric layer and in which the ratio of the average cross-sectional diameter of the grains to the grain length is from 1/50 to 1/14.
22. An angular velocity sensor, comprising a substrate including a fixed portion and at least a pair of vibrating portions extending from the fixed portion in a predetermined direction, in which a first electrode layer, an orientation control layer, a piezoelectric layer and a second electrode layer are layered in this order at least on each of the vibrating portions of the substrate, and the second electrode layer on each of the vibrating portions is patterned into at least one driving electrode for vibrating the vibrating portion in a width direction thereof and at least one detection electrode for detecting a displacement of the vibrating portion in a thickness direction thereof,
wherein the orientation control layer is made of a cubic or tetragonal perovskite oxide;
the piezoelectric layer has a rhombohedral or tetragonal crystalline structure and is made of lead zirconate titanate to which a Pb-containing complex perovskite compound whose chemical formula is expressed as Pb(A a B b )O 3 has been added in an amount that is from 1 mol % to 50 mol %; and
crystal grains of the piezoelectric layer are columnar grains which extend thickness-wise in the piezoelectric layer and in which the ratio of the average cross-sectional diameter of the grains to the grain length is from 1/50 to 1/14.
23. An ink jet recording apparatus, comprising an ink jet head, the ink jet head including: a piezoelectric element in which a first electrode layer, an orientation control layer, a piezoelectric layer and a second electrode layer are layered in this order; a vibration layer provided on one surface of the piezoelectric element that is closer to the second electrode layer; and a pressure chamber member bonded to one surface of the vibration layer that is away from the piezoelectric element and including a pressure chamber for storing ink therein, the ink jet head being capable of being relatively moved with respect to a recording medium, in which while the ink jet head is moved with respect to the recording medium, the vibration layer is displaced in a thickness direction by a piezoelectric effect of the piezoelectric layer of the piezoelectric element in the ink jet head so as to discharge the ink out of the pressure chamber through a nozzle hole communicated to the pressure chamber onto the recording medium, thereby recording information,
wherein the orientation control layer of the piezoelectric element of the ink jet head is made of a cubic or tetragonal perovskite oxide;
the piezoelectric layer has a rhombohedral or tetragonal crystalline structure and is made of lead zirconate titanate to which a Pb-containing complex perovskite compound whose chemical formula is expressed as Pb(A a B b )O 3 has been added in an amount that is from 1 mol % to 50 mol %; and
crystal grains of the piezoelectric layer are columnar grains which extend thickness-wise in the piezoelectric layer and in which the ratio of the average cross-sectional diameter of the grains to the grain length is from 1/50 to 1/14.
24. An ink jet recording apparatus, comprising an ink jet head, the ink jet head including: a piezoelectric element in which a first electrode layer, an orientation control layer, a piezoelectric layer and a second electrode layer are layered in this order; a vibration layer provided on one surface of the piezoelectric element that is closer to the first electrode layer; and a pressure chamber member bonded to one surface of the vibration layer that is away from the piezoelectric element and including a pressure chamber for storing ink therein, the ink jet head being capable of being relatively moved with respect to a recording medium, in which while the ink jet head is moved with respect to the recording medium, the vibration layer is displaced in a thickness direction by a piezoelectric effect of the piezoelectric layer of the piezoelectric element in the ink jet head so as to discharge the ink out of the pressure chamber through a nozzle hole communicated to the pressure chamber onto the recording medium, thereby recording information,
wherein the orientation control layer of the piezoelectric element of the ink jet head is made of a cubic or tetragonal perovskite oxide;
the piezoelectric layer has a rhombohedral or tetragonal crystalline structure and is made of lead zirconate titanate to which a Pb-containing complex perovskite compound whose chemical formula is expressed as Pb(A a B b )O 3 has been added in an amount that is from 1 mol % to 50 mol %; and
crystal grains of the piezoelectric layer are columnar grains which extend thickness-wise in the piezoelectric layer and in which the ratio of the average cross-sectional diameter of the grains to the grain length is from 1/50 to 1/14.