title: Enhanced cooperative interactions at the nanoscale in spin-crossover materials with a first-order phase transition.
abstract: We analyzed the size effect on a first-order spin transition governed by elastic interactions. This study was performed in the framework of a nonextensive thermodynamic core-shell model. When decreasing the particle size, differences in surface energies between the two phases lead to the shrinking of the thermal hysteresis width, the lowering of the transition temperature, and the increase of residual fractions at low temperature, in good agreement with recent experimental observations on spin transition nanomaterials. On the other hand, a modification of the particle-matrix interface may allow for the existence of the hysteresis loop even at very low sizes. In addition, an unexpected reopening of the hysteresis, when the size decreases, is also possible due to the hardening of the nanoparticles at very small sizes, which we deduced from the size dependence of the Debye temperature of a series of coordination nanoparticles.
authors.affiliation: LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France.
authors.forename: Gautier
authors.initials: G
authors.lastname: Félix
authors.affiliation: LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France.
authors.forename: William
authors.initials: W
authors.lastname: Nicolazzi
authors.affiliation: LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Salmon
authors.affiliation: LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France.
authors.forename: Gábor
authors.initials: G
authors.lastname: Molnár
authors.affiliation: Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, Chimie Moléculaire et Organisation du Solide, Université Montpellier II, 34095 Montpellier, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Perrier
authors.affiliation: Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, Chimie Moléculaire et Organisation du Solide, Université Montpellier II, 34095 Montpellier, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Maurin
authors.affiliation: Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, Chimie Moléculaire et Organisation du Solide, Université Montpellier II, 34095 Montpellier, France.
authors.forename: Joulia
authors.initials: J
authors.lastname: Larionova
authors.affiliation: Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, Chimie Moléculaire et Organisation du Solide, Université Montpellier II, 34095 Montpellier, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Long
authors.affiliation: Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, Chimie Moléculaire et Organisation du Solide, Université Montpellier II, 34095 Montpellier, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Guari
authors.affiliation: LCC, CNRS and Université de Toulouse (UPS, INP), 205 route de Narbonne, F-31077 Toulouse, France.
authors.forename: Azzedine
authors.initials: A
authors.lastname: Bousseksou