Stabilisation and modification of the electrical properties of ferroelectric BaTi2O5

Lead Research Organisation: University of Sheffield
Department Name: Materials Science and Engineering


BaTi2O5 is a recently-discovered ferroelectric with a high Curie temperature of ~ 470oC. It has a highly anisotropic crystal structure with a permittivity in the polar direction of ~ 20,000 but a much reduced value of ~ 100 in directions perpendicular to the polar axis. Although single crystals of BaTi2O5 can be grown from the melt and it can also be synthesised as a fine powder by low temperature sol-gel routes, it appears not to be a thermodynamically stable phase and cannot be prepared using the usual high temperature ceramic routes, thereby limiting its range of applications due to inherent fabrication difficulties. We have conducted preliminary phase diagram experiments which showed that BaTi2O5 has a very limited range of stability between 1324 and 1326oC, which coincides with melting temperatures in this region of the BaO-TiO2 phase diagram. We propose to build on this result and investigate the effect of dopants on the thermodynamic stability of BaTi2O5 with a view to reducing the temperature of its lower limit of stability, thereby permitting the processing and fabrication of ceramics. Any dopants that substitute into the BaTi2O5 lattice are very likely to modify both Tc and the electrical properties: e', tan d and piezo-electric coefficients; the effect of dopants on these properties will be surveyed.


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Prades M (2008) Polymorphism of BaTiO 3 Acceptor Doped with Mn 3+ , Fe 3+ , and Ti 3+ in Journal of the American Ceramic Society

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Zhang L (2008) Ferroelectric Aging and Recoverable Electrostrain in BaTi 0.98 Ca 0.02 O 2.98 Ceramics in Journal of the American Ceramic Society

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Zhu N (2009) Formation and Stability of Ferroelectric BaTi 2 O 5 in Journal of the American Ceramic Society

Description We now have a much better understanding of the stability and electrical properties of the new ferroelectric material BaTi2O5
Exploitation Route Ferroelectrical materials such as this have potential applications as a new high temperature capacitor. Studies continue, both by ourselves and researchers in Japan, on the modification of the electrical properties by the doping and fabrication of materials in a suitable form for application purposes
Sectors Electronics,Energy

Description They formed the basis of five publications in scientific journals and have lead to follow-on studies in our laboratory on materials fabrication using sol-gel processing techniques for possible high temperature dielectric applications
First Year Of Impact 2010
Sector Education,Electronics,Energy
Impact Types Economic