Synthesis and growth of novel materials at extreme conditions of pressure and temperature
Event details
| Date | 27.11.2012 |
| Hour | 11:15 |
| Speaker | Dr. Amir Abbas Haghighirad, Physikalisches Institut, Goethe University, Frankfurt am Main, Germany |
| Location | |
| Category | Conferences - Seminars |
Crystal growth under high pressure offers chances to manufacture novel materials in high-purity single crystalline form to explore the physics of electrons subject to strongly competing interactions. In this regime of strong “frustration” the quantum nature of the electron spin and orbital motion become very important and can lead to completely new properties. Synthesizing materials in this regime is very challenging as often extreme conditions of high pressures and temperatures are required to stabilize a desired composition, ion valence or crystal structure, but it potentially can open up new avenues for synthesizing novel materials. The multianvil technique is a very effective and flexible way which combines comparatively large sample volumes, high pressures and high temperatures. With our current setup, pressures up to 8 GPa are reached in a sample volume (~ 80 mm3). A small graphite tube serves as a resistance furnace for temperatures up to 1500 °C. We have investigated the synthesis and crystal growth of pyrochlore vanadates A2V2O7 (A = Er, Ho, Dy and Y). The application of high pressure is necessary for the formation and stability of these compounds.
For the first time, A2V2O7 (A = Er, Ho, Dy and Y) single crystals were grown by using grain growth method at high pressure (HP) of 5.0-5.5 GPa and high temperatures (HT) of ~ 1200 °C in a 6-8 multianvil appartus.
Currently we study the preparation and crystal growth of the superconducting iron-based layered compounds, e.g. 11-compound FeSe1-x and the 1111-system LaFePnO1-xFx (Pn = P, As, Sb). Despite the structural simplicity of FeSe among the Fe-based-compounds, crystal growth of this compound is very challenging taking into account the different polymorphs and the extreme sensitivity of superconductivity to small deviations depending on the elemental composition and synthesis conditions, temperature or pressure. I will discuss different aspects of high pressure technique and its impact in solid-state physics.
For the first time, A2V2O7 (A = Er, Ho, Dy and Y) single crystals were grown by using grain growth method at high pressure (HP) of 5.0-5.5 GPa and high temperatures (HT) of ~ 1200 °C in a 6-8 multianvil appartus.
Currently we study the preparation and crystal growth of the superconducting iron-based layered compounds, e.g. 11-compound FeSe1-x and the 1111-system LaFePnO1-xFx (Pn = P, As, Sb). Despite the structural simplicity of FeSe among the Fe-based-compounds, crystal growth of this compound is very challenging taking into account the different polymorphs and the extreme sensitivity of superconductivity to small deviations depending on the elemental composition and synthesis conditions, temperature or pressure. I will discuss different aspects of high pressure technique and its impact in solid-state physics.
Practical information
- Informed public
- Free
Organizer
- ICMP/LQM (Arnaud Magrez)
Contact
- Prof. H. Ronnow