US5555219A
Expired / Lapsed
US
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Ferroelectric material, and semiconductor memory, optical recording medium and micro-displacement control device using the ferroelectric material
Assignee: Ricoh Co Ltd
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Filing: 1993-12-16
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Granted: 1996-09-10
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Expires: 2013-12-16
Abstract
Abstract A ferroelectric material has hysteresis characteristics in the polarization--electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from the antiferroelectric state to a ferroelectric phase with the application of an electric field thereto, and a phase transition electric field with which the antiferroelectric-to-ferroelectric phase transition is carried out is shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out has a negative value. A semiconductor non-volatile memory, a rewritable optical recording medium, a highly integrated micro-displacement control device, and a shape memory device, each utilizing the above-mentioned ferroelectric material, are provided.
Inventors
- 👤 Yoshikazu Akiyama
- 👤 Sachiko Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:07
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/48; C04B35/49; C04B35/491; C04B35/493; C04B35/495; C04B35/497; C04B35/499
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
91 words
A ferroelectric material which has hysteresis characteristics in the polarization--electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferroelectric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferroelectric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value.
Claim 2
Dependent Claim
91 words
A ferroelectric material which has hysteresis characteristics in the polarization--electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferroelectric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferroelectric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value.
Claim 3
Dependent Claim
113 words
A non-volatile semiconductor memory capable of obtaining bit information by detecting the polarizing direction of a piezoelectric material, said piezoelectric material being a ferroelectric material which has hysteresis characteristics in the polarization-electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferroelectric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferroelectric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value.
Claim 4
Dependent Claim
113 words
A non-volatile semiconductor memory capable of obtaining bit information by detecting the polarizing direction of a piezoelectric material, said piezoelectric material being a ferroelectric material which has hysteresis characteristics in the polarization-electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferroelectric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferroelectric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value.
Claim 5
Dependent Claim
101 words
An optical recording medium comprising a recording layer which comprises a ferroelectric material which has hysteresis characteristics in the polarization-electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferroelectric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferro-electric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value.
Claim 6
Dependent Claim
101 words
An optical recording medium comprising a recording layer which comprises a ferroelectric material which has hysteresis characteristics in the polarization-electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferroelectric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferro-electric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value.
Claim 7
Independent Claim
158 words
A method of recording information in an optical recording medium comprising a recording layer which comprises a ferroelectric material which has hysteresis characteristics in the polarization-electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferro-electric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferro-electric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value, comprising the step of applying a laser beam to said recording layer with a predetermined bias electric field being applied thereto to perform said structural phase transition in a portion of said recording layer to which said laser beam is applied, thereby recording information therein in the form of recording bits.
Claim 8
Independent Claim
158 words
A method of recording information in an optical recording medium comprising a recording layer which comprises a ferroelectric material which has hysteresis characteristics in the polarization-electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferro-electric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferro-electric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value, comprising the step of applying a laser beam to said recording layer with a predetermined bias electric field being applied thereto to perform said structural phase transition in a portion of said recording layer to which said laser beam is applied, thereby recording information therein in the form of recording bits.
Claim 9
Dependent Claim
96 words
A micro-displacement control device comprising a ferroelectric material which has hysteresis characteristics in the polarization-electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferro-electric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferro-electric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value.
Claim 10
Dependent Claim
96 words
A micro-displacement control device comprising a ferroelectric material which has hysteresis characteristics in the polarization-electric field relationship thereof, exhibits an antiferroelectric phase at room temperature, and carries out a structural phase transition from said antiferro-electric phase to a ferroelectric phase with the application of an electric field thereto, with a phase transition electric field with which the antiferro-electric-to-ferroelectric phase transition is carried out being shifted to a lower electric field with the elevation of the temperature thereof, and a phase transition electric field with which a ferroelectric-to-antiferroelectric phase transition is carried out having a negative value.
Claim 11
Dependent Claim
29 words
The micro-displacement control device as claimed in claim 5, wherein said ferroelectric material comprises a zirconium oxide tin oxide lead based composite oxide having a pseudo-tetragonal perovskite crystal structure.
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