Studies of hysteresis and quantum tunnelling of the magnetisation in dysprosium(iii) single molecule magnets

Fabrizio Ortu; Daniel Reta; You-Song Ding; Conrad A. P. Goodwin; Matthew P. Gregson; Eric J. L. McInnes; Richard E. P. Winpenny; Yan-Zhen Zheng; Stephen T. Liddle; David P. Mills; Nicholas F. Chilton

doi:10.1039/C9DT01655D

Studies of hysteresis and quantum tunnelling of the magnetisation in dysprosium(iii) single molecule magnets

Fabrizio Ortu, Daniel Reta, You-Song Ding, Conrad A. P. Goodwin, Matthew P. Gregson, Eric J. L. McInnes, Richard E. P. Winpenny, Yan-Zhen Zheng, Stephen T. Liddle, David P. Mills, Nicholas F. Chilton

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Abstract

We report magnetic hysteresis studies of three Dy( iii ) single-molecule magnets (SMMs). The three compounds are [Dy(^tBuO)Cl(THF)₅][BPh₄] (1), [K(18-crown-6-ether)(THF)₂][Dy(BIPM)₂] (2, BIPM = C{PPh₂NSiMe₃}₂), and [Dy(Cp^ttt)₂][B(C₆F₅)₄] (3), chosen as they have large energy barriers to magnetisation reversal of 665, 565, and 1223 cm-1, respectively. There are zero-field steps in the hysteresis loops of all three compounds, that remain in magnetically dilute samples and in samples that are isotopically enriched with ¹⁶⁴Dy, which has no nuclear spin. These results demonstrate that neither dipolar fields nor nuclear hyperfine coupling are solely responsible for the quantum tunnelling of magnetisation at zero field. Analysing their vibrational modes, we find that the modes that most impact the first coordination sphere occur at the lowest energies for 1, at intermediate energies for 2 and at higher energies for 3, in correlation with their coercive fields. Therefore, we suggest that the efficiency of quantum tunnelling of magnetisation is related to molecular flexibility.

Original language	English
Pages (from-to)	8541-8545
Number of pages	5
Journal	Dalton Transactions
Volume	48
Issue number	24
DOIs	https://doi.org/10.1039/C9DT01655D
Publication status	Published - 14 May 2019
Externally published	Yes

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@article{b3d515f6ba5f4426b47172a5d06f5074,

title = "Studies of hysteresis and quantum tunnelling of the magnetisation in dysprosium(iii) single molecule magnets",

abstract = "We report magnetic hysteresis studies of three Dy( iii ) single-molecule magnets (SMMs). The three compounds are [Dy(tBuO)Cl(THF)5][BPh4] (1), [K(18-crown-6-ether)(THF)2][Dy(BIPM)2] (2, BIPM = C{PPh2NSiMe3}2), and [Dy(Cpttt)2][B(C6F5)4] (3), chosen as they have large energy barriers to magnetisation reversal of 665, 565, and 1223 cm-1, respectively. There are zero-field steps in the hysteresis loops of all three compounds, that remain in magnetically dilute samples and in samples that are isotopically enriched with 164Dy, which has no nuclear spin. These results demonstrate that neither dipolar fields nor nuclear hyperfine coupling are solely responsible for the quantum tunnelling of magnetisation at zero field. Analysing their vibrational modes, we find that the modes that most impact the first coordination sphere occur at the lowest energies for 1, at intermediate energies for 2 and at higher energies for 3, in correlation with their coercive fields. Therefore, we suggest that the efficiency of quantum tunnelling of magnetisation is related to molecular flexibility.",

author = "Fabrizio Ortu and Daniel Reta and You-Song Ding and Goodwin, {Conrad A. P.} and Gregson, {Matthew P.} and McInnes, {Eric J. L.} and Winpenny, {Richard E. P.} and Yan-Zhen Zheng and Liddle, {Stephen T.} and Mills, {David P.} and Chilton, {Nicholas F.}",

year = "2019",

month = may,

day = "14",

doi = "10.1039/C9DT01655D",

language = "English",

volume = "48",

pages = "8541--8545",

journal = "Dalton Transactions",

issn = "1477-9226",

publisher = "Royal Society of Chemistry",

number = "24",

}

TY - JOUR

T1 - Studies of hysteresis and quantum tunnelling of the magnetisation in dysprosium(iii) single molecule magnets

AU - Ortu, Fabrizio

AU - Reta, Daniel

AU - Ding, You-Song

AU - Goodwin, Conrad A. P.

AU - Gregson, Matthew P.

AU - McInnes, Eric J. L.

AU - Winpenny, Richard E. P.

AU - Zheng, Yan-Zhen

AU - Liddle, Stephen T.

AU - Mills, David P.

AU - Chilton, Nicholas F.

PY - 2019/5/14

Y1 - 2019/5/14

N2 - We report magnetic hysteresis studies of three Dy( iii ) single-molecule magnets (SMMs). The three compounds are [Dy(tBuO)Cl(THF)5][BPh4] (1), [K(18-crown-6-ether)(THF)2][Dy(BIPM)2] (2, BIPM = C{PPh2NSiMe3}2), and [Dy(Cpttt)2][B(C6F5)4] (3), chosen as they have large energy barriers to magnetisation reversal of 665, 565, and 1223 cm-1, respectively. There are zero-field steps in the hysteresis loops of all three compounds, that remain in magnetically dilute samples and in samples that are isotopically enriched with 164Dy, which has no nuclear spin. These results demonstrate that neither dipolar fields nor nuclear hyperfine coupling are solely responsible for the quantum tunnelling of magnetisation at zero field. Analysing their vibrational modes, we find that the modes that most impact the first coordination sphere occur at the lowest energies for 1, at intermediate energies for 2 and at higher energies for 3, in correlation with their coercive fields. Therefore, we suggest that the efficiency of quantum tunnelling of magnetisation is related to molecular flexibility.

AB - We report magnetic hysteresis studies of three Dy( iii ) single-molecule magnets (SMMs). The three compounds are [Dy(tBuO)Cl(THF)5][BPh4] (1), [K(18-crown-6-ether)(THF)2][Dy(BIPM)2] (2, BIPM = C{PPh2NSiMe3}2), and [Dy(Cpttt)2][B(C6F5)4] (3), chosen as they have large energy barriers to magnetisation reversal of 665, 565, and 1223 cm-1, respectively. There are zero-field steps in the hysteresis loops of all three compounds, that remain in magnetically dilute samples and in samples that are isotopically enriched with 164Dy, which has no nuclear spin. These results demonstrate that neither dipolar fields nor nuclear hyperfine coupling are solely responsible for the quantum tunnelling of magnetisation at zero field. Analysing their vibrational modes, we find that the modes that most impact the first coordination sphere occur at the lowest energies for 1, at intermediate energies for 2 and at higher energies for 3, in correlation with their coercive fields. Therefore, we suggest that the efficiency of quantum tunnelling of magnetisation is related to molecular flexibility.

U2 - 10.1039/C9DT01655D

DO - 10.1039/C9DT01655D

M3 - Article

SN - 1477-9226

VL - 48

SP - 8541

EP - 8545

JO - Dalton Transactions

JF - Dalton Transactions

IS - 24

ER -

Studies of hysteresis and quantum tunnelling of the magnetisation in dysprosium(iii) single molecule magnets

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