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

Gavin A. Craig, Arup Sarkar, Christopher H. Woodall, Moya A. Hay, Katie E. R. Marriott, Konstantin V. Kamenev, Stephen A. Moggach, Euan K. Brechin, Simon Parsons, Gopalan Rajaraman, Mark Murrie

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Understanding and controlling magnetic anisotropy at the level of a single metal ion is vital if the miniaturisation 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 d(x2-y2) and d(xy) 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.

Original languageEnglish
Pages (from-to)1551-1559
Number of pages9
JournalChemical Science
Volume9
Issue number6
DOIs
Publication statusPublished - 14 Feb 2018
Externally publishedYes

Cite this

Craig, G. A., Sarkar, A., Woodall, C. H., Hay, M. A., Marriott, K. E. R., Kamenev, K. V., ... Murrie, M. (2018). Probing the origin of the giant magnetic anisotropy in trigonal bipyramidal Ni(II) under high pressure. Chemical Science, 9(6), 1551-1559. https://doi.org/10.1039/c7sc04460g
Craig, Gavin A. ; Sarkar, Arup ; Woodall, Christopher H. ; Hay, Moya A. ; Marriott, Katie E. R. ; Kamenev, Konstantin V. ; Moggach, Stephen A. ; Brechin, Euan K. ; Parsons, Simon ; Rajaraman, Gopalan ; Murrie, Mark. / Probing the origin of the giant magnetic anisotropy in trigonal bipyramidal Ni(II) under high pressure. In: Chemical Science. 2018 ; Vol. 9, No. 6. pp. 1551-1559.
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Craig, GA, Sarkar, A, Woodall, CH, Hay, MA, Marriott, KER, Kamenev, KV, Moggach, SA, Brechin, EK, Parsons, S, Rajaraman, G & Murrie, M 2018, 'Probing the origin of the giant magnetic anisotropy in trigonal bipyramidal Ni(II) under high pressure' Chemical Science, vol. 9, no. 6, pp. 1551-1559. https://doi.org/10.1039/c7sc04460g

Probing the origin of the giant magnetic anisotropy in trigonal bipyramidal Ni(II) under high pressure. / Craig, Gavin A.; Sarkar, Arup; Woodall, Christopher H.; Hay, Moya A.; Marriott, Katie E. R.; Kamenev, Konstantin V.; Moggach, Stephen A.; Brechin, Euan K.; Parsons, Simon; Rajaraman, Gopalan; Murrie, Mark.

In: Chemical Science, Vol. 9, No. 6, 14.02.2018, p. 1551-1559.

Research output: Contribution to journalArticle

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T1 - Probing the origin of the giant magnetic anisotropy in trigonal bipyramidal Ni(II) under high pressure

AU - Craig, Gavin A.

AU - Sarkar, Arup

AU - Woodall, Christopher H.

AU - Hay, Moya A.

AU - Marriott, Katie E. R.

AU - Kamenev, Konstantin V.

AU - Moggach, Stephen A.

AU - Brechin, Euan K.

AU - Parsons, Simon

AU - Rajaraman, Gopalan

AU - Murrie, Mark

PY - 2018/2/14

Y1 - 2018/2/14

N2 - Understanding and controlling magnetic anisotropy at the level of a single metal ion is vital if the miniaturisation 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 d(x2-y2) and d(xy) 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.

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KW - ION-ANISOTROPY

KW - COMPLEXES

KW - DESIGN

KW - ACCURATE

KW - RN

KW - DISTORTIONS

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DO - 10.1039/c7sc04460g

M3 - Article

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JO - Chemical Science

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Craig GA, Sarkar A, Woodall CH, Hay MA, Marriott KER, Kamenev KV et al. Probing the origin of the giant magnetic anisotropy in trigonal bipyramidal Ni(II) under high pressure. Chemical Science. 2018 Feb 14;9(6):1551-1559. https://doi.org/10.1039/c7sc04460g