scholarly journals Design of Bistable Gold@Spin-Crossover Core-Shell Nanoparticles Showing Large Electrical Responses for the Spin Switching

2019 ◽  
Author(s):  
Ramón Torres-Cavanillas ◽  
Rocher Sanchis-Gual ◽  
Julien Dugay ◽  
Marc Coronado-Puchau ◽  
Dr. Mónica Giménez Marqués ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Hysteresis Loops ◽  
Large Change ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Simple Protocol ◽  
Order Of Magnitude ◽  
Core Shell Nanoparticles

<p>A simple protocol to prepare core-shell gold@spin-crossover (Au@SCO) nanoparticles (NPs) based on the 1D spin-crossover [Fe(Htrz)<sub>2</sub>(trz)](BF<sub>4</sub>) coordination polymer is reported. The synthesis relies on a two-step approach consisting on a partial surface ligand substitution of the citrate-stabilized Au NPs followed by the controlled growth of a very thin layer of the SCO polymer. As a result, colloidally stable core@shell spherical NPs of 19 nm in size exhibiting a narrow distribution in sizes have been obtained, revealing a switchable SCOshell of <i>ca.</i>4 nm. Temperature-dependent charge transport measurements of an electrical device based on assemblies of these Au@SCO NPs display well-defined, reproducible and sharp thermal hysteresis loops in the conductance near room temperature. This device is characterized both, by a large change in conductance upon spin state switching, and a remarkable transition abruptness, as compared with other memory devices based on the pristine SCO NPs. As a result, the sensitivity of the device to the spin transition is dramatically improved, with values for the ON/OFF ratio which are an order of magnitude better than the best ones obtained in previous SCO devices.</p>

scholarly journals Design of Bistable Gold@Spin-Crossover Core-Shell Nanoparticles Showing Large Electrical Responses for the Spin Switching

2019 ◽  
Author(s):  
Ramón Torres-Cavanillas ◽  
Rocher Sanchis-Gual ◽  
Julien Dugay ◽  
Marc Coronado-Puchau ◽  
Dr. Mónica Giménez Marqués ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Hysteresis Loops ◽  
Large Change ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Simple Protocol ◽  
Order Of Magnitude ◽  
Core Shell Nanoparticles

<p>A simple protocol to prepare core-shell gold@spin-crossover (Au@SCO) nanoparticles (NPs) based on the 1D spin-crossover [Fe(Htrz)<sub>2</sub>(trz)](BF<sub>4</sub>) coordination polymer is reported. The synthesis relies on a two-step approach consisting on a partial surface ligand substitution of the citrate-stabilized Au NPs followed by the controlled growth of a very thin layer of the SCO polymer. As a result, colloidally stable core@shell spherical NPs of 19 nm in size exhibiting a narrow distribution in sizes have been obtained, revealing a switchable SCOshell of <i>ca.</i>4 nm. Temperature-dependent charge transport measurements of an electrical device based on assemblies of these Au@SCO NPs display well-defined, reproducible and sharp thermal hysteresis loops in the conductance near room temperature. This device is characterized both, by a large change in conductance upon spin state switching, and a remarkable transition abruptness, as compared with other memory devices based on the pristine SCO NPs. As a result, the sensitivity of the device to the spin transition is dramatically improved, with values for the ON/OFF ratio which are an order of magnitude better than the best ones obtained in previous SCO devices.</p>

scholarly journals Plasmon-assisted spin transition in gold nanostar@Spin Crossover heterostructures

2021 ◽  
Author(s):  
Roger Sanchis-Gual ◽  
Ramón Torres-Cavanillas ◽  
Marc Coronado Puchau ◽  
Mónica Giménez-Marqués ◽  
Eugenio Coronado
Keyword(s):  
Coordination Polymer ◽  
Spin Crossover ◽  
Spin Transition ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Gold Nanostar ◽  
Core Shell Nanoparticles

Herein we report the design of core@shell nanoparticles formed by a metallic Au nanostar core and a spin-crossover shell based on the magnetic coordination polymer [Fe(Htrz)2(trz)](BF4). This procedure is general...

Compensation effects and relation between the activation energy of spin transition and the hysteresis loop width for an iron(ii) complex

2016 ◽  
Vol 18 (25) ◽  
pp. 16690-16699 ◽  
Author(s):  
Mark B. Bushuev ◽  
Denis P. Pishchur ◽  
Elena B. Nikolaenkova ◽  
Viktor P. Krivopalov
Keyword(s):  
Hysteresis Loop ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Activation Barrier ◽  
Spin Transition ◽  
Hysteresis Loops ◽  
High Activation ◽  
Activation Barriers ◽  
Spin Crossover Complexes ◽  
Hysteresis Loop Width

Wide thermal hysteresis loops for iron(ii) spin crossover complexes are associated with high activation barriers: the higher the activation barrier, the wider the hysteresis loop for a series of related spin crossover systems.

scholarly journals Design of Bistable Gold@Spin‐Crossover Core–Shell Nanoparticles Showing Large Electrical Responses for the Spin Switching

2019 ◽  
Vol 31 (27) ◽  
pp. 1900039 ◽  
Author(s):  
Ramón Torres‐Cavanillas ◽  
Roger Sanchis‐Gual ◽  
Julien Dugay ◽  
Marc Coronado‐Puchau ◽  
Mónica Giménez‐Marqués ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles ◽  
Spin Switching ◽  
Electrical Responses

scholarly journals Elastic Origin of the Unsymmetrical Thermal Hysteresis in Spin Crossover Materials: Evidence of Symmetry Breaking

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 828
Author(s):  
Mamadou Ndiaye ◽  
Nour El Islam Belmouri ◽  
Jorge Linares ◽  
Kamel Boukheddaden
Keyword(s):  
Symmetry Breaking ◽  
High Spin ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Hysteresis Loops ◽  
Point Of View ◽  
Self Organization ◽  
Spin States ◽  
Heating And Cooling

The jungle of experimental behaviors of spin-crossover materials contains a tremendous number of unexpected behaviors, among which, the unsymmetrical hysteresis loops having different shapes on heating and cooling, that we often encounter in literature. Excluding an extra effect of crystallographic phase transitions, we study here these phenomena from the point of view of elastic modeling and we demonstrate that a simple model accounting for the bond lengths misfits between the high-spin and low-spin states is sufficient to describe the situation of unsymmetrical hysteresis showing plateaus at the transition only on cooling or on heating branches. The idea behind this effect relates to the existence of a discriminant elastic frustration in the lattice, which expresses only along the high-spin to low-spin transition or in the opposite side. The obtained two-step transitions showed characteristics of self-organization of the spin states under the form of stripes, which we explain as an emergence process of antagonist directional elastic interactions inside the lattice. The analysis of the spin state transformation inside the plateau on cooling in terms of two sublattices demonstrated that the elastic-driven self-organization of the spin states is accompanied with a symmetry breaking.

Dependence of the Hysteresis Characteristics of Co-Au Core-Shell Nanoparticles on the Size of the Particles

2015 ◽  
Vol 233-234 ◽  
pp. 554-557
Author(s):  
Maria A. Chernova ◽  
Leonid L. Afremov ◽  
Ilia G. Iliushin
Keyword(s):  
Experimental Data ◽  
Saturation Magnetization ◽  
Coercive Field ◽  
Hysteresis Loops ◽  
Core Shell ◽  
Residual Saturation ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles ◽  
Hysteresis Characteristics ◽  
Good Agreement

Hysteresis loops were plotted and dependence of coercive field, residual saturation magnetization and saturation magnetization on size of the Co-Au core-shell nanoparticles were calculated within the developed model. It was shown that decrease in the size of nanoparticles leads to decrease of the abovementioned characteristics. Calculated values of the hysteresis characteristics ​​are in good agreement with the experimental data.

scholarly journals Hybrid spin-crossover nanostructures

2014 ◽  
Vol 5 ◽  
pp. 2230-2239 ◽  
Author(s):  
Carlos M Quintero ◽  
Gautier Félix ◽  
Iurii Suleimanov ◽  
José Sánchez Costa ◽  
Gábor Molnár ◽  
...  
Keyword(s):  
Thin Films ◽  
Physical Properties ◽  
Recent Progress ◽  
Spin Crossover ◽  
Core Shell ◽  
Multilayer Thin Films ◽  
Shell Nanoparticles ◽  
Spin Crossover Complexes ◽  
Review Reports ◽  
Core Shell Nanoparticles

This review reports on the recent progress in the synthesis, modelling and application of hybrid spin-crossover materials, including core–shell nanoparticles and multilayer thin films or nanopatterns. These systems combine, often in synergy, different physical properties (optical, magnetic, mechanical and electrical) of their constituents with the switching properties of spin-crossover complexes, providing access to materials with unprecedented capabilities.

Asymmetric hysteresis loops and its dependence on magnetic anisotropy in exchange biased Co/CoO core-shell nanoparticles

2012 ◽  
Vol 101 (23) ◽  
pp. 232405 ◽  
Author(s):  
Sayan Chandra ◽  
Hafsa Khurshid ◽  
Manh-Huong Phan ◽  
Hariharan Srikanth
Keyword(s):  
Magnetic Anisotropy ◽  
Hysteresis Loops ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

scholarly journals Superparamagnetic Fe/Au Nanoparticles and Their Feasibility for Magnetic Hyperthermia

2021 ◽  
Vol 11 (14) ◽  
pp. 6637
Author(s):  
Mohamed F. Sanad ◽  
Bianca P. Meneses-Brassea ◽  
Dawn S. Blazer ◽  
Shirin Pourmiri ◽  
George C. Hadjipanayis ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hysteresis Loops ◽  
Magnetic Hyperthermia ◽  
Core Shell ◽  
Face Centered Cubic ◽  
Shell Nanoparticles ◽  
Face Centered ◽  
Shell Particles ◽  
Core Shell Nanoparticles ◽  
Alternating Magnetic Fields

Today, magnetic hyperthermia constitutes a complementary way to cancer treatment. This article reports a promising aspect of magnetic hyperthermia addressing superparamagnetic and highly Fe/Au core-shell nanoparticles. Those nanoparticles were prepared using a wet chemical approach at room temperature. We found that the as-synthesized core shells assembled with spherical morphology, including face-centered-cubic Fe cores coated and Au shells. The high-resolution transmission microscope images (HRTEM) revealed the formation of Fe/Au core/shell nanoparticles. The magnetic properties of the samples showed hysteresis loops with coercivity (HC) close to zero, revealing superparamagnetic-like behavior at room temperature. The saturation magnetization (MS) has the value of 165 emu/g for the as-synthesized sample with a Fe:Au ratio of 2:1. We also studied the feasibility of those core-shell particles for magnetic hyperthermia using different frequencies and different applied alternating magnetic fields. The Fe/Au core-shell nanoparticles achieved a specific absorption rate of 50 W/g under applied alternating magnetic field with amplitude 400 Oe and 304 kHz frequency. Based on our findings, the samples can be used as a promising candidate for magnetic hyperthermia for cancer therapy.

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