23 April 2020

Molecular magnetic building blocks

(top) Schematic of the new silicon-mediated replacement of fluorine atoms, resulting in the magnetic building block molecule shown at upper right. (bottom) Frequency vs magnetic field plot from which the much stronger magnetism along the z-axis (the steeper red line) can be deduced for the molecule with spin S = 3/2  and “M” representing a Rhenium atom. (top) Schematic of the new silicon-mediated replacement of fluorine atoms, resulting in the magnetic building block molecule shown at upper right. (bottom) Frequency vs magnetic field plot from which the much stronger magnetism along the z-axis (the steeper red line) can be deduced for the molecule with spin S = 3/2 and “M” representing a Rhenium atom.

This study reports the first transition metal compounds featuring mixed fluoride–cyanide ligands. A significant enhancement of the magnetic anisotropy, as compared to the pure fluoride ligated compounds, is demonstrated by combined analysis of high-field electron paramagnetic resonance (HF-EPR) spectroscopy and magnetization measurements.

What did scientists discover?

This study reports the first transition metal molecules featuring both fluorine and cyanide ligands (see "branches" attached to the metal atom (M) in the molecules at the top of the figure). A strong and significant enhancement of the non-uniformity of the magnetism, the "magnetic anisotropy" for the trans-[ReIVF4(CN)2]2- complex (shown in the upper right) was discovered by combined high-field magnetization and electron paramagnetic resonance (EPR) spectroscopy (see lower Figure).

THE TOOLS THEY USED

This research was conducted in the MagLab 15/17T SC magnet and spectrometer at the MagLab's EMR Facility.

Why is this important?

This research highlights an efficient new strategy for synthesizing molecular building blocks based on heavier transition metals that feature relatively large magnetic moments and very strong magnetic anisotropy. Such building blocks may form the basis for future high-performance magnetic materials used in high-density information storage applications.

Who did the research?

J.-L. Liu1,2,3, K.S. Pedersen1,4, S.M. Greer5, I. Oyarzabal1,6, A. Mondal1,7, S. Hill5, F. Wilhelm8, A. Rogalev8, A. Tressaud2, E. Durand2, J.R. Long9, R. Clérac1,2

1CRPP, Bordeaux; 2Univ. Bordeaux; 3Sun Yat-Sen Univ.; 4TU Denmark; 5FSU & National MagLab; 6Univ. Basque Country; 7IIS Bangalore; 8ESRF Grenoble; 9UC Berkeley & LBNL

Why did they need the MagLab?

EPR provides a direct measure of magnetic anisotropy, evidenced by the different steepness of the red, green, and blue lines in the lower figure. Magnetic anisotropy gives rise to broad EPR spectra that require very large magnetic fields in order to resolve all of the relevant details. For this reason, the measurements had to be performed at the MagLab’s Electron Magnetic Resonance facility.

Details for scientists

Funding

This research was funded by the following grants: G.S. Boebinger (NSF DMR-1157490, DMR-1644779); J.R. Long (NSF CHE-1800252); R. Clérac (ANR & CNRS)


For more information, contact Stephen Hill.

Details

  • Research Area: Chemistry - Inorganic and Coordination, Chemistry - Materials, Chemistry - Nanomaterials,Magnetism and Magnetic Materials
  • Research Initiatives: Materials
  • Facility / Program: EMR
  • Year: 2020
Last modified on 23 April 2020