Invited Speaker
Dr. Nikita Liedienov
Associate Professor, State Key Laboratory of High Pressure and Superhard MaterialsJilin University, China
Speech Title: Anomalous Behaviour of the Spin Transition in the FeII-based Spin-Crossover Compounds under High Pressure
Abstract: Spin-crossover (SCO) materials exhibit reversible high-spin (HS, S = 2) ↔ low-spin (LS, S = 0) transitions in response to external stimuli, making them promising candidates for adaptive sensing, energy conversion, and molecular-scale information processing. In this work, a new Fe(II)-based SCO complex was synthesized and systematically investigated using high-pressure structural, vibrational, optical, thermal, and magnetic characterization techniques, including X-ray diffraction, Raman and infrared spectroscopy, UV–Vis absorption spectroscopy, differential scanning calorimetry, and SQUID magnetometry. Structural studies reveal a pressure-induced spin transition from the HS state (< 0.7 GPa) through a mixed-spin region (~0.8–2.0 GPa) to a complete LS state (> 2.5 GPa). In contrast, the magnetic measurements demonstrate that increasing pressure shifts the spin-transition temperature toward higher temperatures, broadens the thermal hysteresis from 60 to 130 K, and stabilizes the complete HS state in the LS region at pressures above 0.1 GPa. These results provide new insights into the structure–property relationships governing Fe(II)-based SCO systems and highlight their potential for the development of next-generation molecular memory materials.
Keywords: Spin-crossover phenomenon, spin transition, magnetic susceptibility, Fe(II), high pressure
Biography: Associate Professor Nikita Liedienov graduated from Donetsk National University (Donetsk, Ukraine) in 2014 and received his Ph.D. in Solid State Physics from the B. I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, in 2018 (Kharkiv, Ukraine). Since 2018, he has been working at Jilin University (Changchun, China), where he was appointed Associate Professor in 2023. His research focuses on structural, magnetic, transport, magnetocaloric, barocaloric, and ferroelectric properties of multifunctional materials, particularly perovskites, under extreme conditions: high pressure, temperature, magnetic, and electric fields. He has authored more than 100 publications, including 39 journal articles, 3 patents, and 83 abstracts at international conferences with over 889 citations and an h-index of 21. He has participated in seven research projects, led two of them, and serves as a reviewer for 22 international scientific journals.