About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
|
| Presentation Title |
Stoichiometry Compensating Planar Defects in Sr-Rich SrTiO<sub>3</sub> |
| Author(s) |
Sipei Li, Paul Salvador, Gregory S. Rohrer |
| On-Site Speaker (Planned) |
Sipei Li |
| Abstract Scope |
Between 1200 °C and 1400 °C, SrTiO3 is reported to be in equilibrium with Sr3Ti2O7. However, when small excesses (< 5 mol%) of SrO are added to SrTiO3, instead of forming Sr3Ti2O7 precipitates, individual planar faults of SrO form on (100) planes. These defects are known as Ruddlesden-Popper (RP) faults in perovskites, but these and similar defects in other materials can be classified as stoichiometry compensating planar defects. There are two possible mechanisms for the formation of these faults. One is kinetic – they would precipitate as a bulk phase given sufficient time. The second is that they are thermodynamically stabilized, perhaps by entropy. We report a series of experiments designed to test these two formation mechanisms. Because the RP faults appear in SrTiO3 after mixing with small amounts of Sr3Ti2O7, it is concluded that the crystal containing planar faults is more stable than the two bulk stoichiometric phases. |