Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 4: Spin structures and magnetic phase transitions
MA 4.12: Vortrag
Montag, 12. März 2018, 12:30–12:45, EB 202
Time-resolved nuclear resonance scattering experiments on spin crossover complexes — •Sakshath Sadashivaiah1, Kevin Jenni1, Andreas Omlor1, Christina-Sophie Müller1, Lena Scherthan1, Marcus Herlitschke2, Ilya Sergeev2, Hans-Christian Wille2, Ralf Röhlsberger2, Juliusz Wolny1, and Volker Schünemann1 — 1Department of Physics, University of Kaiserslautern, 67663 Kaiserslautern, Germany — 2Deutsches Elektronen synchrotron (DESY), 22607 Hamburg, Germany
The high spin (HS) - low spin (LS) phase transition in laser excited spin crossover complexes occurs though an intermediate state of co-operative lattice vibrations. The mechanism is debated because the phonon density of states (DOS) is only partially accessed in previous studies such as Raman scattering or reflectivity [1]. Through time-resolved Nuclear Inelastic Scattering (NIS) experiments, we study the full DOS of the ground and excited states at 100 K in the [Fe(PM-BIA)2(NCS)2] complex using 14.4 keV synchrotron radiation (SR) pulses. The sample was excited by time-delayed laser pulses derived from a 531 nm source, which was triggered at every alternate SR pulse. By performing NIS (and Nuclear forward scattering) using the SR pulses accompanying the laser pulses, we measured the excited state [2]. The alternate SR pulses probe the ground state. We follow the effect of the laser pulses by comparing the resulting spectra with the static HS and LS spectra.
[1] R. Bertoni et al, Nat. Mater. 15, 606 (2016).
[2] S. Sakshath et al, Hyperfine Interact. 238, 89 (2017)