Seminar "Non-collinear magnetism of cobalt-benzene clusters"

Title: "Non-collinear magnetism of cobalt-benzene clusters"

Speaker: Dr. Jhon González, Centro de Física de Materiales (CSIC-UPV/EHU)-Material Physics Center (MPC)

Abstract:

In recent years, single-molecule magnets have been of interest in both basic and
applied science. The polynuclear molecules containing transition metals atoms
have interesting magnetic properties turning in potential candidates to store and
process information at molecular level. The physical properties of some of these
molecular magnets involve non-collinear magnetism that arises from the geometric
frustration of antiferromagnetic interactions. Some experiments have found that
cobalt clusters easily react with benzene, leading to the production of stable and
non-reactive complexes with multiple adsorbed benzene rings [1].
We use different density functional theory (DFT) methods to study the
experimentally relevant three cobalt atoms surrounded by benzene rings (Co3 Bz3).
A proper treatment of electron-nuclei and electron-electron interactions including
spin-orbit effects can be found in the full-potential linearized augmented plane
wave methods (LAPW). Within this approach, we show that the organic ligands
lead to non-collinear magnetic orders. The ground state changes from a
ferromagnetic collinear solution for the bare Co3 molecule, to a family of noncollinear
solutions [2] for Co3 Bz3 explaining the null signal obtained in the
XMCD measurements [3].
In this talk we will discuss the computational challenges involved in the search of
the physical and magnetic properties of small magnetic clusters. Later, we try to
generalize the results obtained in cobalt clusters to other first-row transition metal
clusters [4].
[1] T. Kurikawa, et al., Zeitschrift für Physik D Atoms, Molecules and Clusters 40,
65 (1997)
[2] J. W. González, et al., Phys. Chem. Chem. Phys. 19, 14854 (2017).
[3] S. Akin, et al., The Journal of Phys. Chem. Lett. 7, 4568 (2016).
[4] T. Alonso, et al., The Journal of Phys. Chem. C 121, 25554 (2017) and arXiv:
1710.07519.