Dr. Martina Vrankić [Division of Materials Physics, Ruđer Bošković Institute, Croatia]

Title: Where crystallography meets materials science

Language: English presentation

Time: 14:00 - 15:00 PM, Thursday, Jan. 4, 2024

Place: Onsite: Conference room A417, HPSTAR (Beijing)            Online: Tencent Meeting: https://meeting.tencent.com/dm/fyLGdl29QCC7  Meeting ID: 438-598-496

Host:  Dr. Takeshi Nakagawa

Abstract:

Understanding how materials behave under non-ambient conditions is very important for both making devices and keeping them in good shape. In this talk, two different areas of materials science study that use different methods, but both have fundamental crystallography in the background will be presented.It is known, for example, that artificial materials that can store and release molecular oxygen are a good place to start looking for new uses that might help cut down on energy use and the damage that it does to the environment. In this context, the reversible intake/release of oxygen within the BaAl2O4 material is investigated, as evidenced by unexpected magnetic ordering. Indeed, the magnetic measurements reveal that oxygen is stored in the form of condensed matter, creating a kind of low dimensional, chain-like assembly within the tunnels of the BaAl2O4 structure. Oxygen is adsorbed simply by staying in air, at ambient conditions, and released relatively quickly by staying in the He or another gas atmosphere with a pressure of several millibars even at 300 K.For the selected organic-inorganic hybrid material, however, the collected powder X-ray diffraction and structural evolution data under high pressure underline the necessity of this characterization method, without which it would be impossible to correlate structural and sensitive physical and photophysical behaviour. A collection of various non-ambient data measured for the hybrid molecular ferroelectric ([N(C2H5)3CH3][FeBr4]) has deciphered the flexible physical and photophysical behavior at pressures above 30 GPa, leading to a revresible band narrowing at relatively moderate pressure points and reversible piezochromic changes in the electronic scenario.Deciphering the arrangement and bonding of atoms in crystalline solids and the geometric structure of crystal lattices is essential for linking the structure and properties of materials.