Probing the origin of the giant magnetic anisotropy in trigonal bipyramidal Ni(II) under high pressure

Craig, G. A. et al. (2018) Probing the origin of the giant magnetic anisotropy in trigonal bipyramidal Ni(II) under high pressure. Chemical Science, 9(6), pp. 1551-1559. (doi: 10.1039/C7SC04460G)

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Understanding and controlling magnetic anisotropy at the level of a single metal ion is vital if the miniaturization of data storage is to continue to evolve into transformative technologies. Magnetic anisotropy is essential for a molecule-based magnetic memory as it pins the magnetic moment of a metal ion along the easy axis. Devices will require deposition of magnetic molecules on surfaces, where changes in molecular structure can significantly alter magnetic properties. Furthermore, if we are to use coordination complexes with high magnetic anisotropy as building blocks for larger systems we need to know how magnetic anisotropy is affected by structural distortions. Here we study a trigonal bipyramidal nickel(II) complex where a giant magnetic anisotropy of several hundred wavenumbers can be engineered. By using high pressure, we show how the magnetic anisotropy is strongly influenced by small structural distortions. Using a combination of high pressure X-ray diffraction, ab initio methods and high pressure magnetic measurements, we find that hydrostatic pressure lowers both the trigonal symmetry and axial anisotropy, while increasing the rhombic anisotropy. The ligand-metal-ligand angles in the equatorial plane are found to play a crucial role in tuning the energy separation between the dx2-y2 and dxy orbitals, which is the determining factor that controls the magnitude of the axial anisotropy. These results demonstrate that the combination of high pressure techniques with ab initio studies is a powerful tool that gives a unique insight into the design of systems that show giant magnetic anisotropy.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Craig, Dr Gavin and Marriott, Miss Katie and Hay, Ms Moya Anne and Murrie, Professor Mark
Authors: Craig, G. A., Sarkar, A., Woodall, C. H., Hay, M. A., Marriott, K., Kamenev, K. V., Moggach, S. A., Brechin, E. K., Parsons, S., Rajaraman, G., and Murrie, M.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Chemical Science
Publisher:Royal Society of Chemistry
ISSN (Online):2041-6539
Published Online:19 December 2017
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in Chemical Science 9(6):1551-1559
Publisher Policy:Reproduced under a Creative Commons License
Data DOI:10.5525/gla.researchdata.491

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
592671Mapping magnetic anistrophy: rational design of nanomagnets with increased blocking temperatures.Mark MurrieEngineering and Physical Sciences Research Council (EPSRC)EP/J018147/1CHEM - CHEMISTRY
618561Pressure-tuning interactions in molecule-based magnetsMark MurrieEngineering and Physical Sciences Research Council (EPSRC)EP/K033662/1CHEM - CHEMISTRY
696981Putting the Squeeze on Molecule-Based MagnetsMark MurrieEngineering and Physical Sciences Research Council (EPSRC)EP/N01331X/1CHEM - CHEMISTRY