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Eric Freysz - One of the best experts on this subject based on the ideXlab platform.
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Study of the fast photoswitching of spin crossover nanoparticles outside and inside their thermal Hysteresis Loop
Applied Physics Letters, 2013Co-Authors: Geoffrey Gallé, Céline Etrillard, Jérôme Degert, François Guillaume, Jean-françois Létard, Eric FreyszAbstract:We have studied the low spin to high spin phase transition induced by nanosecond laser pulses outside and within the thermal Hysteresis Loop of the [Fe(Htrz)2 trz](BF4)2-H2O spin crossover nanoparticles. We demonstrate that, whatever the temperature of the compound, the photo-switching is achieved in less than 12.5 ns. Outside the Hysteresis Loop, the photo-induced high spin state remains up to 100 μs and then relaxes. Within the thermal Hysteresis Loop, the photo-induced high spin state remains as long as the temperature of the sample is kept within the thermal Loop. A Raman study indicates that the photo-switching can be completed using single laser pulse excitation.
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Observation of an asymmetry in the thermal Hysteresis Loop at the scale of a single spin-crossover particle
Chemical Physics Letters, 2009Co-Authors: Carole Arnaud, Jean-françois Létard, Eric Freysz, Thibaut Forestier, Nathalie Daro, Gilles Pauliat, Gérald RoosenAbstract:We have studied the spin-crossover phenomenon of single isolated micro-particles using a Differential Interference Microscope (DIC) operating in transmission mode. For that we have selected the [Fe(NH2-trz)3]Br2-2.5H2O coordination polymer complex well-known to exhibit, at room temperature, a spin transition with a large thermal Hysteresis Loop. The comparison of the thermal Hysteresis Loop of several isolated micro-particles demonstrates some heterogeneity and also an obvious asymmetry of the cycle. The warming branch clearly appears more abrupt than the cooling branch. We also report some correlations between the threshold temperature and the size of the particles.
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Single laser pulse induces spin state transition within the Hysteresis Loop of an iron compound
Chemical Physics Letters, 2004Co-Authors: Eric Freysz, S. Montant, Sylvie Létard, Jean-françois LétardAbstract:Within the thermal Hysteresis Loop of the [Fe(PM-BiA)2(NCS)2] compound, a single laser pulse of 14 mJ cm−2 induces a photo-conversion from the low spin (LS, S = 0) to the high spin (HS, S = 2) state of the Fe2+ metallic center...
Jean-françois Létard - One of the best experts on this subject based on the ideXlab platform.
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Study of the fast photoswitching of spin crossover nanoparticles outside and inside their thermal Hysteresis Loop
Applied Physics Letters, 2013Co-Authors: Geoffrey Gallé, Céline Etrillard, Jérôme Degert, François Guillaume, Jean-françois Létard, Eric FreyszAbstract:We have studied the low spin to high spin phase transition induced by nanosecond laser pulses outside and within the thermal Hysteresis Loop of the [Fe(Htrz)2 trz](BF4)2-H2O spin crossover nanoparticles. We demonstrate that, whatever the temperature of the compound, the photo-switching is achieved in less than 12.5 ns. Outside the Hysteresis Loop, the photo-induced high spin state remains up to 100 μs and then relaxes. Within the thermal Hysteresis Loop, the photo-induced high spin state remains as long as the temperature of the sample is kept within the thermal Loop. A Raman study indicates that the photo-switching can be completed using single laser pulse excitation.
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Observation of an asymmetry in the thermal Hysteresis Loop at the scale of a single spin-crossover particle
Chemical Physics Letters, 2009Co-Authors: Carole Arnaud, Jean-françois Létard, Eric Freysz, Thibaut Forestier, Nathalie Daro, Gilles Pauliat, Gérald RoosenAbstract:We have studied the spin-crossover phenomenon of single isolated micro-particles using a Differential Interference Microscope (DIC) operating in transmission mode. For that we have selected the [Fe(NH2-trz)3]Br2-2.5H2O coordination polymer complex well-known to exhibit, at room temperature, a spin transition with a large thermal Hysteresis Loop. The comparison of the thermal Hysteresis Loop of several isolated micro-particles demonstrates some heterogeneity and also an obvious asymmetry of the cycle. The warming branch clearly appears more abrupt than the cooling branch. We also report some correlations between the threshold temperature and the size of the particles.
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Single laser pulse induces spin state transition within the Hysteresis Loop of an iron compound
Chemical Physics Letters, 2004Co-Authors: Eric Freysz, S. Montant, Sylvie Létard, Jean-françois LétardAbstract:Within the thermal Hysteresis Loop of the [Fe(PM-BiA)2(NCS)2] compound, a single laser pulse of 14 mJ cm−2 induces a photo-conversion from the low spin (LS, S = 0) to the high spin (HS, S = 2) state of the Fe2+ metallic center...
Jose Rodellar - One of the best experts on this subject based on the ideXlab platform.
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variation of the Hysteresis Loop with the bouc wen model parameters
Nonlinear Dynamics, 2007Co-Authors: Fayçal Ikhouane, Jorge E. Hurtado, Jose RodellarAbstract:The Bouc–Wen model for smooth Hysteresis has received an increasing interest in the last few years due to the ease of its numerical implementation and its ability to represent a wide range of Hysteresis Loop shapes. This model consists of a first-order nonlinear differential equation that contains some parameters that can be chosen, using identification procedures, to approximate the behavior of given physical hysteretic system. Despite a large body of literature dedicated to the Bouc–Wen model, the relationship between the parameters that appear in the differential equation and the shape of the obtained Hysteresis Loop is little understood. The objective of this paper is to fill this gap by analytically exploring this relationship using a new form of the model called the normalized one. The mathematical framework introduced in this study formalizes the vague notion of “Loop shape" into precise quantities whose variation with the Bouc–Wen model parameters is analyzed. In light of this analysis, the parameters of Bouc–Wen model are re-interpreted.
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Variation of the Hysteresis Loop with the Bouc–Wen model parameters
Nonlinear Dynamics, 2007Co-Authors: Fayçal Ikhouane, Jorge E. Hurtado, Jose RodellarAbstract:The Bouc–Wen model for smooth Hysteresis has received an increasing interest in the last few years due to the ease of its numerical implementation and its ability to represent a wide range of Hysteresis Loop shapes. This model consists of a first-order nonlinear differential equation that contains some parameters that can be chosen, using identification procedures, to approximate the behavior of given physical hysteretic system. Despite a large body of literature dedicated to the Bouc–Wen model, the relationship between the parameters that appear in the differential equation and the shape of the obtained Hysteresis Loop is little understood. The objective of this paper is to fill this gap by analytically exploring this relationship using a new form of the model called the normalized one. The mathematical framework introduced in this study formalizes the vague notion of “Loop shape" into precise quantities whose variation with the Bouc–Wen model parameters is analyzed. In light of this analysis, the parameters of Bouc–Wen model are re-interpreted.
Denis Ostrovskii - One of the best experts on this subject based on the ideXlab platform.
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bidirectional photo switching of the spin state of iron ii ions in a triazol based spin crossover complex within the thermal Hysteresis Loop
Chemical Physics Letters, 2009Co-Authors: Nawel Ould Moussa, Denis Ostrovskii, Victor Martinez Garcia, Gabor Molnar, Koichiro Tanaka, Ana B GasparAbstract:Abstract We have investigated the effect of short laser pulses (532 nm, 4 ns, −2 ) on the spin state of iron(II) ions in the spin crossover compound {[Fe II (Htrz) 2 (trz)](BF 4 )} within the Hysteresis region of the high-spin (HS) to low-spin (LS) first-order thermal phase transition. Using Raman spectroscopy we have evidenced quasi-complete HS → LS as well as LS → HS photo-conversions, which can be induced by a single laser shot in the descending (351 K) and ascending (378 K) branches of the Hysteresis Loop, respectively. No effect has been observed, however, close to the center of the Hysteresis Loop even for repeated exposures.
Nawel Ould Moussa - One of the best experts on this subject based on the ideXlab platform.
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bidirectional photo switching of the spin state of iron ii ions in a triazol based spin crossover complex within the thermal Hysteresis Loop
Chemical Physics Letters, 2009Co-Authors: Nawel Ould Moussa, Denis Ostrovskii, Victor Martinez Garcia, Gabor Molnar, Koichiro Tanaka, Ana B GasparAbstract:Abstract We have investigated the effect of short laser pulses (532 nm, 4 ns, −2 ) on the spin state of iron(II) ions in the spin crossover compound {[Fe II (Htrz) 2 (trz)](BF 4 )} within the Hysteresis region of the high-spin (HS) to low-spin (LS) first-order thermal phase transition. Using Raman spectroscopy we have evidenced quasi-complete HS → LS as well as LS → HS photo-conversions, which can be induced by a single laser shot in the descending (351 K) and ascending (378 K) branches of the Hysteresis Loop, respectively. No effect has been observed, however, close to the center of the Hysteresis Loop even for repeated exposures.