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Precise measurement of angles between two magnetic moments and their configurational stability in single-molecule magnets

Westerström, Rasmus LU ; Dubrovin, Vasilii ; Junghans, Katrin ; Schlesier, Christin ; Büchner, Bernd ; Avdoshenko, Stanislav M. ; Popov, Alexey A. ; Kostanyan, Aram ; Dreiser, Jan and Greber, Thomas (2021) In Physical Review B 104(22).
Abstract

A key parameter for the low-temperature magnetic coupling of in dinuclear lanthanide single-molecule magnets (SMMs) is the barrier UFA resulting from the exchange and dipole interactions between the two 4f moments. Here we extend the pseudospin model previously used to describe the ground state of dinuclear endofullerenes to account for variations in the orientation of the single-ion anisotropy axes and apply it to the two SMMs Dy2ScN@C80 and Dy2TiC@C80. While x-ray magnetic circular dichroism (XMCD) indicates the same Jz=15/2 Dy ground state in both molecules, the Dy-Dy coupling strength and the stability of magnetization is distinct. We demonstrate that both the magnitude of the barrier UFA and the angle between the two 4f moments are... (More)

A key parameter for the low-temperature magnetic coupling of in dinuclear lanthanide single-molecule magnets (SMMs) is the barrier UFA resulting from the exchange and dipole interactions between the two 4f moments. Here we extend the pseudospin model previously used to describe the ground state of dinuclear endofullerenes to account for variations in the orientation of the single-ion anisotropy axes and apply it to the two SMMs Dy2ScN@C80 and Dy2TiC@C80. While x-ray magnetic circular dichroism (XMCD) indicates the same Jz=15/2 Dy ground state in both molecules, the Dy-Dy coupling strength and the stability of magnetization is distinct. We demonstrate that both the magnitude of the barrier UFA and the angle between the two 4f moments are determined directly from precise temperature-dependent magnetization data to an accuracy better than 1. The experimentally found angles between the 4f moments are in excellent agreement with calculated angles between the quantization axes of the two Dy ions. Theory indicates a larger deviation of the orientation of the Dy magnetic moments from the Dy bond axes to the central ion in Dy2TiC@C80. This may explain the lower stability of the magnetization in Dy2TiC@C80, although it exhibits a ∼49% stronger exchange coupling than in Dy2ScN@C80.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B
volume
104
issue
22
article number
A40
publisher
American Physical Society
external identifiers
  • scopus:85121273053
ISSN
2469-9950
DOI
10.1103/PhysRevB.104.224401
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2021 American Physical Society.
id
0f860232-f6bd-4ffe-a31f-0eed6e870049
date added to LUP
2022-01-19 09:44:59
date last changed
2025-04-04 14:39:55
@article{0f860232-f6bd-4ffe-a31f-0eed6e870049,
  abstract     = {{<p>A key parameter for the low-temperature magnetic coupling of in dinuclear lanthanide single-molecule magnets (SMMs) is the barrier UFA resulting from the exchange and dipole interactions between the two 4f moments. Here we extend the pseudospin model previously used to describe the ground state of dinuclear endofullerenes to account for variations in the orientation of the single-ion anisotropy axes and apply it to the two SMMs Dy2ScN@C80 and Dy2TiC@C80. While x-ray magnetic circular dichroism (XMCD) indicates the same Jz=15/2 Dy ground state in both molecules, the Dy-Dy coupling strength and the stability of magnetization is distinct. We demonstrate that both the magnitude of the barrier UFA and the angle between the two 4f moments are determined directly from precise temperature-dependent magnetization data to an accuracy better than 1. The experimentally found angles between the 4f moments are in excellent agreement with calculated angles between the quantization axes of the two Dy ions. Theory indicates a larger deviation of the orientation of the Dy magnetic moments from the Dy bond axes to the central ion in Dy2TiC@C80. This may explain the lower stability of the magnetization in Dy2TiC@C80, although it exhibits a ∼49% stronger exchange coupling than in Dy2ScN@C80. </p>}},
  author       = {{Westerström, Rasmus and Dubrovin, Vasilii and Junghans, Katrin and Schlesier, Christin and Büchner, Bernd and Avdoshenko, Stanislav M. and Popov, Alexey A. and Kostanyan, Aram and Dreiser, Jan and Greber, Thomas}},
  issn         = {{2469-9950}},
  language     = {{eng}},
  month        = {{12}},
  number       = {{22}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review B}},
  title        = {{Precise measurement of angles between two magnetic moments and their configurational stability in single-molecule magnets}},
  url          = {{http://dx.doi.org/10.1103/PhysRevB.104.224401}},
  doi          = {{10.1103/PhysRevB.104.224401}},
  volume       = {{104}},
  year         = {{2021}},
}