Enhancing Magnetic Hysteresis in Single-Molecule Magnets by Ligand Functionalization

Ke-xin Yu; Jon G.c. Kragskow; You-song Ding; Yuan-qi Zhai; Daniel Reta; Nicholas F. Chilton; Yan-zhen Zheng

doi:10.1016/j.chempr.2020.04.024

Enhancing Magnetic Hysteresis in Single-Molecule Magnets by Ligand Functionalization

Ke-xin Yu, Jon G.c. Kragskow, You-song Ding, Yuan-qi Zhai, Daniel Reta, Nicholas F. Chilton, Yan-zhen Zheng

University of Manchester

Research output: Contribution to journal › Article › peer-review

117 Citations (SciVal)

Abstract

Design criteria for dysprosium(III) single-molecule magnets (SMMs) with large thermal energy barriers to magnetic reversal have been established and proven, and the challenge to enhance performance is in understanding and controlling electron-vibration coupling that is the origin of magnetic reversal. We have prepared an SMM, [Dy(L)2(py)5][BPh4] 1 (HL = (S)-(-)-1-phenylethanol), based on the archetype [Dy(OtBu)2(py)5][BPh4] 2. Compounds 1 and 2 have similarly large energy barriers of Ueff = 1,130(20) cm−1 and Ueff = 1,250(10) cm−1, and yet 1 shows magnetic hysteresis at a far higher temperature of 22 K cf. TH = 4 K for 2. Ab initio calculation of the electron-vibration coupling and spin dynamics shows that substitution of the alkoxide ligand in fact enhances relaxation over the energy barrier for 1 compared with 2, in agreement with experiment, and that the higher temperature of magnetic hysteresis likely owes to reduced quantum tunneling at low temperatures.

Original language	English
Pages (from-to)	1777-1793
Journal	Chem
Volume	6
Issue number	7
DOIs	https://doi.org/10.1016/j.chempr.2020.04.024
Publication status	Published - 28 May 2020
Externally published	Yes

Bibliographical note

We acknowledge the Natural Science Foundation of China (21620102002 and
21773130), Xi’an Municipal Bureau of Science and Technology (201805056ZD7CG40), Cyrus Chung Ying Tang Foundation, State Key Laboratory for Mechanical Behavior of Materials, the Fundamental Research Funds for the Central Universities (P.R.C.), EPSRC (U.K., EP/P002560/1), and the University of Manchester for funding and support. We also thank the Instrument Analysis Centre of Xi’an Jiaotong University for the measurement on dilution ratio and the Computational Shared Facility at The University of Manchester. K.-X.Y. thanks the China Scholarship Council for a research scholarship and N.F.C. thanks the University of Manchester for a Presidential Fellowship and the Royal Society for a University Research Fellowship. We thank Prof. Richard Winpenny and Dr David
Mills for useful discussions

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10.1016/j.chempr.2020.04.024Licence: CC BY

https://linkinghub.elsevier.com/retrieve/pii/S2451929420301960Licence: CC BY

Cite this

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title = "Enhancing Magnetic Hysteresis in Single-Molecule Magnets by Ligand Functionalization",

abstract = "Design criteria for dysprosium(III) single-molecule magnets (SMMs) with large thermal energy barriers to magnetic reversal have been established and proven, and the challenge to enhance performance is in understanding and controlling electron-vibration coupling that is the origin of magnetic reversal. We have prepared an SMM, [Dy(L)2(py)5][BPh4] 1 (HL = (S)-(-)-1-phenylethanol), based on the archetype [Dy(OtBu)2(py)5][BPh4] 2. Compounds 1 and 2 have similarly large energy barriers of Ueff = 1,130(20) cm−1 and Ueff = 1,250(10) cm−1, and yet 1 shows magnetic hysteresis at a far higher temperature of 22 K cf. TH = 4 K for 2. Ab initio calculation of the electron-vibration coupling and spin dynamics shows that substitution of the alkoxide ligand in fact enhances relaxation over the energy barrier for 1 compared with 2, in agreement with experiment, and that the higher temperature of magnetic hysteresis likely owes to reduced quantum tunneling at low temperatures.",

author = "Ke-xin Yu and Kragskow, {Jon G.c.} and You-song Ding and Yuan-qi Zhai and Daniel Reta and Chilton, {Nicholas F.} and Yan-zhen Zheng",

note = "We acknowledge the Natural Science Foundation of China (21620102002 and 21773130), Xi{\textquoteright}an Municipal Bureau of Science and Technology (201805056ZD7CG40), Cyrus Chung Ying Tang Foundation, State Key Laboratory for Mechanical Behavior of Materials, the Fundamental Research Funds for the Central Universities (P.R.C.), EPSRC (U.K., EP/P002560/1), and the University of Manchester for funding and support. We also thank the Instrument Analysis Centre of Xi{\textquoteright}an Jiaotong University for the measurement on dilution ratio and the Computational Shared Facility at The University of Manchester. K.-X.Y. thanks the China Scholarship Council for a research scholarship and N.F.C. thanks the University of Manchester for a Presidential Fellowship and the Royal Society for a University Research Fellowship. We thank Prof. Richard Winpenny and Dr David Mills for useful discussions ",

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doi = "10.1016/j.chempr.2020.04.024",

language = "English",

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journal = "Chem",

issn = "2451-9294",

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T1 - Enhancing Magnetic Hysteresis in Single-Molecule Magnets by Ligand Functionalization

AU - Yu, Ke-xin

AU - Kragskow, Jon G.c.

AU - Ding, You-song

AU - Zhai, Yuan-qi

AU - Reta, Daniel

AU - Chilton, Nicholas F.

AU - Zheng, Yan-zhen

N1 - We acknowledge the Natural Science Foundation of China (21620102002 and 21773130), Xi’an Municipal Bureau of Science and Technology (201805056ZD7CG40), Cyrus Chung Ying Tang Foundation, State Key Laboratory for Mechanical Behavior of Materials, the Fundamental Research Funds for the Central Universities (P.R.C.), EPSRC (U.K., EP/P002560/1), and the University of Manchester for funding and support. We also thank the Instrument Analysis Centre of Xi’an Jiaotong University for the measurement on dilution ratio and the Computational Shared Facility at The University of Manchester. K.-X.Y. thanks the China Scholarship Council for a research scholarship and N.F.C. thanks the University of Manchester for a Presidential Fellowship and the Royal Society for a University Research Fellowship. We thank Prof. Richard Winpenny and Dr David Mills for useful discussions

PY - 2020/5/28

Y1 - 2020/5/28

N2 - Design criteria for dysprosium(III) single-molecule magnets (SMMs) with large thermal energy barriers to magnetic reversal have been established and proven, and the challenge to enhance performance is in understanding and controlling electron-vibration coupling that is the origin of magnetic reversal. We have prepared an SMM, [Dy(L)2(py)5][BPh4] 1 (HL = (S)-(-)-1-phenylethanol), based on the archetype [Dy(OtBu)2(py)5][BPh4] 2. Compounds 1 and 2 have similarly large energy barriers of Ueff = 1,130(20) cm−1 and Ueff = 1,250(10) cm−1, and yet 1 shows magnetic hysteresis at a far higher temperature of 22 K cf. TH = 4 K for 2. Ab initio calculation of the electron-vibration coupling and spin dynamics shows that substitution of the alkoxide ligand in fact enhances relaxation over the energy barrier for 1 compared with 2, in agreement with experiment, and that the higher temperature of magnetic hysteresis likely owes to reduced quantum tunneling at low temperatures.

AB - Design criteria for dysprosium(III) single-molecule magnets (SMMs) with large thermal energy barriers to magnetic reversal have been established and proven, and the challenge to enhance performance is in understanding and controlling electron-vibration coupling that is the origin of magnetic reversal. We have prepared an SMM, [Dy(L)2(py)5][BPh4] 1 (HL = (S)-(-)-1-phenylethanol), based on the archetype [Dy(OtBu)2(py)5][BPh4] 2. Compounds 1 and 2 have similarly large energy barriers of Ueff = 1,130(20) cm−1 and Ueff = 1,250(10) cm−1, and yet 1 shows magnetic hysteresis at a far higher temperature of 22 K cf. TH = 4 K for 2. Ab initio calculation of the electron-vibration coupling and spin dynamics shows that substitution of the alkoxide ligand in fact enhances relaxation over the energy barrier for 1 compared with 2, in agreement with experiment, and that the higher temperature of magnetic hysteresis likely owes to reduced quantum tunneling at low temperatures.

U2 - 10.1016/j.chempr.2020.04.024

DO - 10.1016/j.chempr.2020.04.024

M3 - Article

SN - 2451-9294

VL - 6

SP - 1777

EP - 1793

JO - Chem

JF - Chem

IS - 7

ER -

Enhancing Magnetic Hysteresis in Single-Molecule Magnets by Ligand Functionalization

Abstract

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