Piezoelectric device, piezoelectric actuator, piezoelectric pump, inkjet recording head, inkjet printer, surface acoustic wave device, thin-film piezoelectric resonator, frequency filter, oscillator, electronic circuit, and electronic instrument
A piezoelectric device includes: a substrate; a first conductive layer formed over the substrate, the first conductive layer including at least one buffer layer formed of a (001) preferentially oriented lanthanum-based layered perovskite compound; a piezoelectric layer formed over the first conductive layer and including a piezoelectric having a perovskite structure; and a second conductive layer electrically connected with the piezoelectric layer.
1. A piezoelectric device comprising:
a first conductive layer including at least one buffer layer formed of a (001) preferentially oriented lanthanum-based layered perovskite compound;
a piezoelectric layer formed over the first conductive layer, the piezoelectric layer having a perovskite structure; and
a second conductive layer formed over the piezoelectric layer.
2. The piezoelectric device as defined in claim 1 , wherein the lanthanum-based layered perovskite compound includes at least one of La 2 NiO 4 , La 3 Ni 2 O 7 , La 4 Ni 3 O 10 , La 2 CuO 4 , and a solid solution of at least two of these compounds.
3. The piezoelectric device as defined in claim 1 , wherein the first conductive layer includes at least one low-resistivity layer formed of a conductive material having a resistivity lower than a resistivity of the lanthanum-based layered perovskite compound.
4. The piezoelectric device as defined in claim 3 ,
wherein the conductive material includes at least one of a metal, an oxide of the metal, and an alloy of the metal; and
wherein the metal is at least one of Pt, Ir, Ru, Ag, Au, Cu, Al, and Ni.
5. The piezoelectric device as defined in claim 3 , wherein the first conductive layer includes the low-resistivity layer and the buffer layer formed over the low-resistivity layer.
6. The piezoelectric device as defined in claim 1 , wherein the first conductive layer includes at least one conductive oxide layer formed of a conductive oxide having a perovskite structure, the conductive oxide being (001) preferentially oriented.
7. The piezoelectric device as defined in claim 6 , wherein the first conductive layer includes the buffer layer and the conductive oxide layer formed over the buffer layer.
8. The piezoelectric device as defined in claim 3 , wherein the first conductive layer includes the low-resistivity layer, the buffer layer formed over the low-resistivity layer, and a conductive oxide layer formed over the buffer layer and formed of a conductive oxide having a perovskite structure, the conductive oxide being (001) preferentially oriented.
9. The piezoelectric device as defined in claim 6 , wherein the conductive oxide includes at least one of CaRuO 3 , SrRuO 3 , BaRuO 3 , SrVO 3 , (La,Sr)MnO 3 , (La,Sr)CrO 3 , (La,Sr)CoO 3 , LaNiO 3 , and a solid solution of at least two of these compounds.
10. The piezoelectric device as defined in claim 1 , wherein the piezoelectric is shown by a general formula ABO 3 , A including Pb, and B including at least one of Zr and Ti.
11. The piezoelectric device as defined in claim 10 , wherein B further includes Nb.
12. The piezoelectric device as defined in claim 1 , wherein the piezoelectric is a rhombohedral crystal or a mixed crystal of a tetragonal crystal and a rhombohedral crystal and is (001) preferentially oriented.