Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 17: Poster Session: Correlated Electrons 1
TT 17.23: Poster
Monday, April 1, 2019, 15:00–18:30, Poster D
Strategies for the design of antiferromagnetically coupled organic spin-dimer systems — •Lars Postulka1, Paul Eibisch1, Ulrich Tutsch1, Bernd Wolf1, Martin Baumgarten2, Kubandiran Kolanji2, and Michael Lang1 — 1Physikalisches Institut, Goethe Universität, SFB/TR49, D-60438 Frankfurt (M) — 2Max-Planck-Institute for Polymer Research, SFB/TR49, D-55128 Mainz
Coupled antiferromagnetic spin-dimer systems based on stable biradicals are recognized as suitable candidates for exploring critical phenomena under well-controlled conditions. Depending on the topology of the inter-dimer couplings, various scenarios can be observed. The work aims at the development of novel spin-dimer systems where the intra- and inter-dimer magnetic exchange interactions can be modified in specific ways. We discuss the magneto-structural correlations of materials based on the stable radical units nitronyl-nitroxides (NN) and imino-nitroxides (IN) bridged with tolan molecules. Furthermore, using low-temperature ac susceptibility and specific heat measurements we characterize the field-induced magnetic phases of these materials and discuss their critical behavior. In addition, we present a new approach for designing the intra- and inter-molecular magnetic exchange interactions based on planar π-bridges of benzo[1,2 -b:4,5 -b’] dithiophene derivatives which connect the stable NN and IN radical units. Our results demonstrate that π-stacking of the planar bridges allows a good control of the inter-molecular magnetic exchange.