Ferroelectric film and method for manufacturing the same
To produce a ferroelectric film formed of a lead-free material. The ferroelectric film according to an aspect of the present invention includes a (K 1−X Na X )NbO 3 film or a BiFeO 3 film having a perovskite structure and a crystalline oxide preferentially oriented to (001) formed on at least one of the upper side and lower side of the (K 1−X Na X )NbO 3 film or BiFeO 3 film, and X satisfies the formula below 0.3≦X≦0.7.
1. A ferroelectric film comprising:
a (K 1−x Na x )NbO 3 film or a BiFeO 3 film having a perovskite structure; and
a crystalline oxide preferentially oriented to (001), formed on at least one of an upper side and lower side of said (K 1−x Na x )NbO 3 film or BiFeO 3 film,
wherein said crystalline oxide is a bismuth layered-structure ferroelectric substance having a pseudo-perovskite structure or a tungsten-bronze type ferroelectric substance,
wherein said bismuth layered-structure ferroelectric substance is (Bi 2 O 2 ) 2 + (A m−1 B m O 3+1 ) 2− (m=1 to 5) or Bi 2 A m−1 B m O 3m+3 (m=1 to 5), and
wherein X satisfies the formula below
0.3≦X≦0.7.
2. The ferroelectric film according to claim 1 ,
wherein said crystalline oxide is formed in an island shape or in a film shape.
3. The ferroelectric film according to claim 1 ,
wherein a thickness of said crystalline oxide is 2 to 30 nm.
4. The ferroelectric film according to claim 1 ,
wherein said (K 1−x Na x )NbO 3 film or BiFeO 3 film is formed by a sol-gel method.
5. The ferroelectric film according to claim 1 ,
wherein a ferroelectric film including said (K 1−x Na x )NbO 3 film or BiFeO 3 film, and said crystalline oxide formed on at least one of the upper side and lower side thereof is stacked.
6. A ferroelectric film comprising:
a (K 1−x Na x )NbO 3 film or a BiFeO 3 film having a perovskite structure; and
a crystalline oxide preferentially oriented to (001), formed on at least one of an upper side and lower side of said (K 1−x Na x )NbO 3 film or BiFeO 3 film,
wherein said crystalline oxide is a tungsten-bronze type ferroelectric substance, and
wherein X satisfies the formula below
0.3<X<0.7.
7. The ferroelectric film according to claim 6 ,
wherein said crystalline oxide is formed in an island shape or in a film shape.
8. The ferroelectric film according to claim 6 ,
wherein a thickness of said crystalline oxide is 2 to 30 nm.
9. The ferroelectric film according to claim 6 ,
wherein said (K 1−x Na x )NbO 3 film or BiFeO 3 film is formed by a sol-gel method.
10. The ferroelectric film according to claim 6 ,
wherein a ferroelectric film including said (K 1−x Na x )NbO 3 film or BiFeO 3 film, and said crystalline oxide formed on at least one of the upper side and lower side thereof is stacked.
11. A ferroelectric film comprising:
a (K 1−x Na x )NbO 3 film or a BiFeO 3 film having a perovskite structure; and
a crystalline oxide preferentially oriented to (001), formed on at least one of an upper side and lower side of said (K 1−x Na x )NbO 3 film or a BiFeO 3 film,
wherein X satisfies the formula below
0.3<X<0.7,
wherein said crystalline oxide is a bismuth layered-structure ferroelectric substance having a pseudo-perovskite structure or a tungsten-bronze type ferroelectric substance, and
wherein said bismuth layered-structure ferroelectric substance is Bi 4 Ti 3 O 12 or (Bi 4−x La x )Ti 3 O 12 , and x satisfies the formula below
0<x<1.
12. The ferroelectric film according to claim 11 ,
wherein said crystalline oxide is formed in an island shape or in a film shape.
13. The ferroelectric film according to claim 11 ,
wherein a thickness of said crystalline oxide is 2 to 30 nm.
14. The ferroelectric film according to claim 11 ,
wherein said (K 1−x Na x )NbO 3 film or BiFeO 3 film is formed by a sol-gel method.
15. The ferroelectric film according to claim 11 ,
wherein a ferroelectric film including said (K 1−x Na x )NbO 3 film or BiFeO 3 film, and said crystalline oxide formed on at least one of the upper side and lower side thereof is stacked.