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MA: Fachverband Magnetismus

MA 41: Surface magnetism I

MA 41.5: Talk

Thursday, March 15, 2018, 10:30–10:45, EB 202

Excited spin-state trapping in spin crossover complexes on ferroelectric substrates — Christian Wäckerlin^1,2, Fabio Donati^3,4, Aparajita Singha¹, Romana Baltic¹, Silvio Decurtins⁵, Shi-Xia Liu⁵, Stefano Rusponi¹, and •Jan Dreiser^1,6 — ¹Ecole Polytechnique Federale de Lausanne, 1015 Lausanne, Switzerland — ²Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland — ³Institute for Basic Science, Seoul 03760, Republic of Korea — ⁴Ewha Womans University, Seoul, Republic of Korea — ⁵University of Bern, 3012 Bern, Switzerland — ⁶Paul Scherrer Institut, 5232 Villigen PSI, Switzerland

Spin crossover molecules exhibit a switchable spin state. Combining them with inorganic ferroelectrics represents a promising path toward magnetoelectric devices. Here we report on a study of films of Fe(II) spin crossover molecules deposited on differently poled ferroelectric PMN-PT ([Pb(Mg_1/3Nb_2/3)O₃]_1−x [PbTiO₃]_x, x = 0.32). X-ray absorption spectroscopy shows complete temperature driven conversion between high-spin and low-spin states independent of the substrate ferroelectric polarization down to 100 K. However, at T = 3 K, in the regime of soft X-ray induced excited spin-state trapping (SOXIESST), the cross section for the SOXIESST process varies by more than one order of magnitude between the two ferroelectric polarizations. We explain our findings by the internal electric fields of the substrates modulating the scattering of X-ray generated secondary electrons at the molecules.