1. The magnetism and ferroelectricity were detected.

2. Piezoelectric and ferroelectric tests imply big piezoelectricity and ferroelectricity.

3. The ferroelectricity means the spontaneous polarization that exists in some materials, and the spontaneous polarization can change its direction when the external electric field alters.

4. With decreasing grain sizes, its crystal structure, ferroelectricity and phase transition temperature all indicated the character of size effect.

5. Multiferroic materials possess both magnetism and ferroelectricity, or a permanent electric polarization.

6. In another words, nc-BaTiO3 is quantum ferroelectricity over some range of particle size.

7. The ultrathin materials which show ferroelectricity and the thickness of which is from several ten nanometers to a few microns are called ferroelectric thin film.

8. Lead titanate series materials present excellent piezoelectricity, ferroelectricity and pyroelectric performance, and have been widely used in intelligent material system.

9. Multiferroic materials are a class of materials that yield simultaneous ferroelectricity and ferromagnetism. They have a potential applications in information storage, spintronic devices and sensors.

10. The ferroelectromagnets is a special compound which shows the coexistence of the spontaneous ferroelectricity and ferromagnetism in the same phase at certain temperature.

11. Physics of ferroelectrics: ferroelectric fatigue, ferroelectric size effect, and impacts of crystalline defects on ferroelectricity .

12. The fabrication of ferroelectric Langmuir-Boldgett (LB) films is introduced. And the study of ferroelectricity of organic LB films and its application in recent years are summarized.

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13. Magnetic relaxor ferroelectric materials (MRF) are compounds in which the relaxor ferroelectricity and ferromagnetic (antiferromagnetic) order coexist simultaneously in certain temperature range.

14. Multiferroic materials are a class of materials that yield simultaneous ferroelectricity and ferromagnetism. It has a potential applications in information storage, spintronic devices and sensors.

15. On the other hand, a high remanent polarization indicates a strong ferroelectricity, which enhances piezoelectric properties.

16. The transition from the clamped state to the free state of the perovskite-type phase, and its effect on ferroelectricity of the samples are emphasized in the discussion.

17. Dynamics theory of ferroelectric polarons, which was developed from the shielding theory of ferroelectricity, is used to explain the polarization switch of ferroelectricity.