Dresden 2020 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 6: Cooperative Phenomena and Phase Transitions (joint session MA/TT)
TT 6.6: Talk
Monday, March 16, 2020, 10:45–11:00, HSZ 401
Spin crossover in mechanically responsive Ni(II)-MOF-74 — •Dijana Žilić1, Krunoslav Užarević1, Senada Muratović1, Bahar Karadeniz1, Tomislav Stolar1, Stipe Lukin1, Ivan Halasz1, Mirta Herak2, Gregor Mali3, Yulia Krupskaya4, and Vladislav Kataev4 — 1R. Bošković Institute, Zagreb, Croatia — 2Institute of Physics, Zagreb, Croatia — 3National Institute of Chemistry, Ljubljana, Slovenia — 4Leibniz IFW, Dresden, Germany
The metal-organic frameworks (MOFs) are the subject of intensive research not only due to potential applications but also due to unresolved magnetic properties. We present here very detailed study of structural and magnetic properties of Ni(II)-MOF-74 compound, investigated by powder X-ray diffraction, infrared and Raman spectroscopy, magnetization measurements, X-band and multifrequency high-field electron spin resonance and solid state nuclear magnetic resonance spectroscopy. Our results show that Ni-MOF-74 can be described as a zig-zag spin chain system with ferromagnetic intrachain and weaker antiferromagnetic (AFM) interchain interaction, with long-range AFM phase transition around 17 K. We also studied how desolvation and amorphization process can influence the chemical and physical properties of Ni-MOF-74. The observed strong differences in magnetic properties of amorphous Ni-MOF-74 were explained by spin crossover from high-spin to low-spin state of Ni(II) ions.
Supported by HRZZ (UIP-2014-09-4744 and IP-2018-01-3168) and DAAD-MZO projects "Magneto-structural correlations in molecular magnetic complexes studied by electron spin resonance spectroscopy".