Effect of alkali cations on the photomagnetic behavior of CoFe Prussian blue analogue nanoparticles embedded in ordered mesoporous silica

Altenschmidt, Laura; Fornasieri, Giulia; Rivière, Éric; Brisset, François; Saint-Martin, R.; Bleuzen, Anne

doi:10.1016/j.crci.2019.06.003

Cited by 3 publications

(1 citation statement)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Experimental and theoretical studies on nanometer scale PBAs and other spin-crossover particles, with sizes on the order of several tens of nanometers, have indicated surface instability increases at small sizes favoring trapping high-spin (HS) species at low temperatures. 19 For example, as particle sizes are reduced, the magnitude of the photoinduced magnetization was shown to decrease for photo-switchable RbCoFe-PBA nanoparticles, 20 and the long-range ferrimagnetic order often observed for RbCoFe-PBAs is suppressed below ∼10 nm particle size. 21 In a study on another PBA, the ferromagnetic CsNiCr-PBA, the smallest single domain particles size is reported as around 14-16 nm.…”

Section: Resultsmentioning

confidence: 99%

Sub-micrometer particle size effects on metastable phases for a photoswitchable Co–Fe Prussian blue analog

Itoi

Maurin

Boukheddaden

et al. 2022

Journal of Applied Physics

View full text Add to dashboard Cite

Metastable phases of the photoswitchable molecular magnet K0.3Co[Fe(CN)6]0.77 ⋅ nH2O in sub-micrometer particles have been structurally investigated by synchrotron powder x-ray diffraction (PXRD) measurements. The K0.3Co[Fe(CN)6]0.77 ⋅ nH2O bulk compound (studied here with a sample having average particle size of 500 nm) undergoes a charge transfer coupled spin transition (CTCST), where spin configurations change between a paramagnetic CoII ( S = 3/2) –FeIII ( S = 1/2) high-temperature (HT) state and a diamagnetic CoIII ( S = 0) –FeII ( S = 0) low-temperature (LT) state. The bulk compound exhibits a unique intermediate (IM) phase, which corresponds to a mixture of HT and LT spin states that depend on the cooling rate. Several hidden metastable HT states emerge as a function of thermal and photo stimuli, namely: (1) a quench (Q) state generated from the HT state by flash cooling, (2) a LTPX state obtained by photoexcitation from the LT state derived by thermal relaxation from the Q state, and (3) an IMPX state accessed by photo-irradiation from the IM state. A sample with a smaller particle size, 135 nm, is investigated for which the particles are on the scale of the coherent LT domains in the IM phase within the larger 500 nm sample. PXRD studies under controlled thermal and/or optical excitations have clarified that the reduction of the particle size profoundly affects the structural changes associated with the CTCST. The unusual IM state is also observed as segregated domains in the 135 nm particle, but the collective structural transformations are more hindered in small particles. The volume change decreases to 2%–3%, almost half the value found for 500 nm particles (5%–8%), even though the linear thermal expansion coefficients are larger for the smaller particles. Furthermore, photoexcitation from the IM and LT states does not turn into single phases in the smaller particles, presumably because of the multiple interfaces and/or internal stress generated by the coexistence of small CoII–FeIII and CoIII–FeII domains in the lattice. Since the reduced particle size limits cooperativity and domain growth in the lattice, CTCST in the small particle sample becomes less sensitive to external stimuli.

show abstract

Section: Resultsmentioning

confidence: 99%

Sub-micrometer particle size effects on metastable phases for a photoswitchable Co–Fe Prussian blue analog

Itoi

Maurin

Boukheddaden

et al. 2022

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

A Peculiar Photo‐Induced Transformation Exalted in Nanometric Size CoFe Prussian Blue Analogs

et al. 2023

Self Cite

View full text Add to dashboard Cite

The discovery of a photomagnetic effect in a CoFe Prussian blue analog (PBA) has triggered a growing interest for photo‐switchable bimetallic cyanide‐bridged systems. Nevertheless, in between cyanide‐bridged extended coordination polymers and discrete molecules, the photo‐switching phenomena are much less well known in nano‐sized materials. A photo‐induced transformation, specific to the nanometric size, is evidenced by magnetometry and by X‐ray absorption spectroscopy at the Co and Fe K‐edges in an alkali cation free Prussian blue analog. The nanoparticles before irradiation can be described as having a core‐shell structure, the core being made of the well‐known fcc‐CoII(HS)FeIII structure of CoFe PBAs while the shell contains CoII ions in octahedral geometry and significantly distorted Fe(CN)6 entities. Irradiation induces a change of the local structures around the transition metal ions, which remain in the same oxidation state, with different behaviors of the Co and Fe sub‐lattices.

show abstract

Photoswitchable high-dimensional CoII–[WV(CN)8] networks: Past, present, and future

Stefańczyk

Ohkoshi

2021

Journal of Applied Physics

View full text Add to dashboard Cite

The research and development of novel bistable magnetic materials is one of the most expanding areas of molecular magnetism. These materials are potentially suitable to be utilized in the construction of modern detectors, high-density data carriers, and devices for energy conversion. Until now, the greatest successes in this field have been achieved for magnetic cyanido-bridged metal assemblies. Among them, the greatest recognition is related to high-dimensional octacyanidometallate-based networks. In this Perspective, two- and three-dimensional cyanido-bridged CoII–[WV(CN)8] networks, exhibiting nontrivial magnetic properties (e.g., electron-transfer-coupled spin transition with broad thermal hysteresis and photoinduced spontaneous magnetization with relatively high Curie temperatures and large magnetic hysteresis loops) and other physicochemical properties (e.g., THz absorption and humidity sensitivity), are collected. All of them are model systems for development of bistable systems due to the presence of wide thermal hysteresis, and the formation of photoinduced metastable state tuned by temperature and wavelength of used light. Additionally, we summarized magnetostructural correlations within them, and we offered some guidelines for the improvement of their performances and the introduction of new functionalities and physicochemical cross-effects.

show abstract

Effect of alkali cations on the photomagnetic behavior of CoFe Prussian blue analogue nanoparticles embedded in ordered mesoporous silica

Cited by 3 publications

References 29 publications

Sub-micrometer particle size effects on metastable phases for a photoswitchable Co–Fe Prussian blue analog

Sub-micrometer particle size effects on metastable phases for a photoswitchable Co–Fe Prussian blue analog

A Peculiar Photo‐Induced Transformation Exalted in Nanometric Size CoFe Prussian Blue Analogs

Photoswitchable high-dimensional CoII–[WV(CN)8] networks: Past, present, and future

Contact Info

Product

Resources

About