High Ferroelectricity: First Method for Production of Bulk SnTiO3
- First method for the preparation of bulk SnTiO3
- Applicable in industry relevant scale
- Access to diverse class of materials
- Validated by scanning transmission electron microscopy
- Ferroelectric random-access memory (FeRAM)
- Tunable capacitors
- Ferroelectric funnel junction element (FTJ)
- Multiferroic element
- Piezoelectric for ultrasound imaging
- Electro-optical elements for data storage
- High precision actuator
SnTiO3 it is a highly promising ferroelectric material but an accordingly large effort to prepare this material in larger amounts remained unsuccessful. Some approaches using temperatures of up to 800°C caused unwanted disproportion and oxidation processes of the initial SN(II). The production of thin film SnTiO3 via atomic layer deposition and pulsed laser deposition was suggested by different groups. However, these expensive methods are not applicable to large industrial scale and the limitation to thin films makes them insufficient for various relevant applications of the material.
To overcome the aforementioned shortcomings, an advanced method for the preparation of bulk SnTiO3 was developed. The method comprises three independent steps.
At first, a mixture of an alkali metal salt and a titanium(IV) oxide are reacted to form layered alkali metal titanate. Ideally, this reaction is conducted at a temperature of 550°C to 650°C over a duration of 12 hours but also other parameters are possible. In the second step of the method, the alkali metal titanate is ion exchanged with tin(II) salt. In this process tin(II) ions are fully or partially substituted for the alkali metal ions and tin-exchanged alkali metal titanate is obtained. In the final step, this material is dehydrated and subsequently annealed in an oxygen free atmosphere at a temperature below the disproportion temperature of tin(II), thus obtaining SnTiO3.
The process according to the invention gives access to new bulk SnTiO3 materials, which can be obtained in a high purity. Surprisingly, the method according to the invention allows the preparation of new crystalline structures of SnTiO3 and SnTi1-xMxO3 for various x and M. The method is scalable and allows the production of ferroelectric SnTiO3 for industrial applications.
PCT (WO2019211372A1), EP, US, JP, CN
Diehl et al. “Structure-Directing Lone Pairs: Synthesis and Structural Characterization of SnTiO3”, Chem. Mater. 30 (2018)
- Ref.-Nr.: 1201-5559-BC (1,0 MiB)
Dr. Bernd Ctortecka, M. Phil.
Telefon: 089 / 29 09 19-20