ELECTRONIC STRUCTURE, MAGNETISM AND DYNAMICS
116 ESRF
Fig. 100: Top: Molecular structure of 1D and 1L. Bottom: Sketch of the experimental setup.
MAGNETOCHIRAL DICHROISM OF LANTHANOID COORDINATION COMPLEXES
This work demonstrates, for the first time, the occurrence of X-ray magnetochiral dichroism in lanthanoid coordination complexes. This peculiar type of dichroism is only present in systems where space inversion and time reversal symmetries are broken simultaneously. The best candidates for its detection are, thus, chiral molecules with a strongly paramagnetic metal centre.
In chiral magnetic materials, the simultaneous breaking of space parity (absence of inversion centre) and time reversal symmetries (finite magnetic moment) can result in magnetoelectric coupling, which reflects the coupling of local electric fields to the molecular magnetic moment. This magnetoelectric coupling can manifest via the occurrence of magnetochiral dichroism, which consists in the differential absorption of unpolarised light with respect to the relative directions of the light propagation
vector and of the externally applied magnetic field, for paramagnetic systems, or the direction of the permanent magnetic moment, for ordered ones. The ability to address and manipulate molecular magnetic moments by local electric fields is of central importance to the perspective of incorporating molecular magnetic materials in future quantum technologies.
Mononuclear lanthanoid (Ln) coordination complexes were proposed to be used as qubits [1]. Furthermore, by taking advantage of the nuclear spin of the metal centre in these complexes, prototypical coupled electronic- qubit-nuclear-qudit systems can be developed [2]. This work demonstrates via the observation, for the first time, of magnetochiral dichroism in mononuclear lanthanoid-based coordination complexes, that these systems also display sizeable magnetoelectric coupling that makes them excellent candidates for manipulation of their magnetic moment at the molecular scale by local electric fields.
Tuning Memristivity by Varying the Oxygen Content in a Mixed Ionic Electronic Conductor, K. Maas (a), E. Villepreux (b), D. Cooper (b), E. Salas-Colera (c,d), J. Rubio-Zuazo (c,d), G. R. Castro (c,d), O. Renault (b), C. Jimenez (a), H. Roussel (a), X. Mescot (e), Q. Rafhay (e), M. Boudard (a)
and M. Burriel (a), Adv. Funct. Mater. 30, 1909942 (2020); https://doi.org/10.1002/ adfm.201909942. (a) Univ. Grenoble Alpes, CNRS, Grenoble INP, LMGP, Grenoble (France) (b) CEA LETI, Université Grenoble Alpes, Grenoble (France)
(c) ESRF (d) Instituto de Ciencia de Materiales de Madrid-ICMM/CSIC Madrid (Spain) (e) Univ. Grenoble Alpes, CNRS, Grenoble INP, IMEP-LAHC, Grenoble (France)
[1] N.K. Upadhyay et al., Adv. Mater. Technol. 4, 1 (2019). [2] R. Waser, J. Nanosci. Nanotechnol. 12, 7628 (2012).
PRINCIPAL PUBLICATION AND AUTHORS
REFERENCES
techniques used in this study strongly suggest that the additional oxygen ions, present in the form of interstitial point defects in L2NO4, are an important, if not essential parameter required to trigger memristivity in Pt/ L2NO4 \Ti
devices. These promising results offer additional insights into the functioning of MIEC-based heterostructures for the development of neuromorphic hardware with analog-type programming capabilities.
