Ultrafast charge-transfer-induced spin transition in cobalt-tungstate molecular photomagnets

Abstract In materials exhibiting photoinduced phase transitions, and in which both charge transfer and spin transitions occur, there has long been a debate about which process drives the phase transition. Herein, we present experimental evidence supporting an optically charge-transfer-induced spin t...

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Main Authors: Kazuki Nakamura, Laurent Guérin, Gaël Privault, Koji Nakabayashi, Marius Hervé, Eric Collet, Shin-ichi Ohkoshi
Format: Article
Language:English
Published: Nature Portfolio 2025-06-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-60401-4
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author Kazuki Nakamura
Laurent Guérin
Gaël Privault
Koji Nakabayashi
Marius Hervé
Eric Collet
Shin-ichi Ohkoshi
author_facet Kazuki Nakamura
Laurent Guérin
Gaël Privault
Koji Nakabayashi
Marius Hervé
Eric Collet
Shin-ichi Ohkoshi
author_sort Kazuki Nakamura
collection DOAJ
description Abstract In materials exhibiting photoinduced phase transitions, and in which both charge transfer and spin transitions occur, there has long been a debate about which process drives the phase transition. Herein, we present experimental evidence supporting an optically charge-transfer-induced spin transition (CTIST) process, as demonstrated through femtosecond optical spectroscopy in two-dimensional cyanido-bridged cobalt-tungstate photomagnets. Optical and magnetic studies revealed that the photoexcitation of the ground low-temperature (LT) CoIII LS-WIV state leads to a photoinduced phase transition towards the CoII HS-WV state, which is similar to the high temperature (HT) state. Ultrafast spectroscopy further indicates that this optical excitation of the intermetallic W-to-Co charge-transfer band produces a transient photoexcited (PE) CoII LS-WV state, which decays within 130 fs through a spin transition towards the CoII HS-WV state. Here we show that the CTIST dynamics corresponds to the CoIII LS-WIV (LT) → CoII LS-WV (PE) → CoII HS-WV (HT) sequence. The present work sheds a new light on understanding optical dynamics underlying the photoinduced phase transitions.
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issn 2041-1723
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spelling doaj-art-18657700edb54f1c95327b08db16bf212025-08-20T03:26:47ZengNature PortfolioNature Communications2041-17232025-06-0116111010.1038/s41467-025-60401-4Ultrafast charge-transfer-induced spin transition in cobalt-tungstate molecular photomagnetsKazuki Nakamura0Laurent Guérin1Gaël Privault2Koji Nakabayashi3Marius Hervé4Eric Collet5Shin-ichi Ohkoshi6Department of Chemistry, School of Science, The University of TokyoDYNACOM IRL2015 University of Tokyo - CNRS - Université de Rennes, Department of ChemistryDYNACOM IRL2015 University of Tokyo - CNRS - Université de Rennes, Department of ChemistryDepartment of Chemistry, School of Science, The University of TokyoDYNACOM IRL2015 University of Tokyo - CNRS - Université de Rennes, Department of ChemistryDYNACOM IRL2015 University of Tokyo - CNRS - Université de Rennes, Department of ChemistryDepartment of Chemistry, School of Science, The University of TokyoAbstract In materials exhibiting photoinduced phase transitions, and in which both charge transfer and spin transitions occur, there has long been a debate about which process drives the phase transition. Herein, we present experimental evidence supporting an optically charge-transfer-induced spin transition (CTIST) process, as demonstrated through femtosecond optical spectroscopy in two-dimensional cyanido-bridged cobalt-tungstate photomagnets. Optical and magnetic studies revealed that the photoexcitation of the ground low-temperature (LT) CoIII LS-WIV state leads to a photoinduced phase transition towards the CoII HS-WV state, which is similar to the high temperature (HT) state. Ultrafast spectroscopy further indicates that this optical excitation of the intermetallic W-to-Co charge-transfer band produces a transient photoexcited (PE) CoII LS-WV state, which decays within 130 fs through a spin transition towards the CoII HS-WV state. Here we show that the CTIST dynamics corresponds to the CoIII LS-WIV (LT) → CoII LS-WV (PE) → CoII HS-WV (HT) sequence. The present work sheds a new light on understanding optical dynamics underlying the photoinduced phase transitions.https://doi.org/10.1038/s41467-025-60401-4
spellingShingle Kazuki Nakamura
Laurent Guérin
Gaël Privault
Koji Nakabayashi
Marius Hervé
Eric Collet
Shin-ichi Ohkoshi
Ultrafast charge-transfer-induced spin transition in cobalt-tungstate molecular photomagnets
Nature Communications
title Ultrafast charge-transfer-induced spin transition in cobalt-tungstate molecular photomagnets
title_full Ultrafast charge-transfer-induced spin transition in cobalt-tungstate molecular photomagnets
title_fullStr Ultrafast charge-transfer-induced spin transition in cobalt-tungstate molecular photomagnets
title_full_unstemmed Ultrafast charge-transfer-induced spin transition in cobalt-tungstate molecular photomagnets
title_short Ultrafast charge-transfer-induced spin transition in cobalt-tungstate molecular photomagnets
title_sort ultrafast charge transfer induced spin transition in cobalt tungstate molecular photomagnets
url https://doi.org/10.1038/s41467-025-60401-4
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