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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 25: Bio- and Molecular Magnetism (joint session MA/CPP)
CPP 25.3: Vortrag
Montag, 16. März 2020, 15:30–15:45, HSZ 101
Intramolecular crossover from 2D diamagnetism to 3D paramagnetism — •Carolin Schmitz-Antoniak1, Alevtina Smekhova2, Detlef Schmitz2, Natalya V. Izarova1, S. Fatemeh Shams1, Maria Stuckart3, Frank M. F. de Groot4, and Paul Kögerler1,5 — 1Forschungszentrum Jülich (PGI-6), 52425 Jülich — 2Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin — 3Inst. f. Chem. Reaktionstechnik, FAU Erlangen-Nürnberg, 91058 Erlangen — 4Inorganic Chemistry and Catalysis Group, Debye Inst. for Nanomaterials Science, Utrecht University, Utrecht 3584 CG — 5Inst. f. Anorgan. Chemie, RWTH Aachen University, 52074 Aachen
In a 2D square-planar coordination with four surrounding oxygen anions, Pd(II) ions in polyoxopalladates are diamagnetic with a large orbital contribution to the magnetic response as revealed by XANES and XMCD. Supported by atomic multiplet calculations the dependence of electronic and magnetic properties on 4d spin-orbit coupling, bond lengths, and delocalization of 4d electrons was investigated. We found that (i) four additional out-of-plane oxygen anions around Pd(II) lead to an effective 3D symmetry causing a paramagnetic response in external magnetic fields and (ii) in the crossover region between common diamagnetism and paramagnetism, the large spin-orbit coupling of Pd facilitates an unusual diamagnetic state modified by significant mixing. Furthermore, by measuring and analysing characteristic fine structures of the diamagnetic states in the XMCD spectrum, we overcome the common limitation of XMCD to ferro/ferrimagnetic and paramagnetic materials in external magnetic fields.