title: Synergy between polymorphism, pressure, spin-crossover and temperature in [Fe(PM-BiA)2(NCS)2]: a neutron powder diffraction investigation.
abstract: The pressure dependencies of the lattice parameters of the spin transition compound [Fe(PM-BiA)2(NCS)2] have been derived from neutron powder diffraction measurements at low temperature. The study of the compound [Fe(PM-BiA)2(NCS)2]-pI has first confirmed the atypical spin crossover behaviour under pressure of this compound that shows a pressure induced structural transition inducing the transformation into a different polymorph, [Fe(PM-BiA)2(NCS)2]-pII. This phenomenon avoids a first-order spin transition in favour of continuous transition around 0.75 GPa at ambient temperature. Low temperature measurements under pressure up to 1.07 GPa allowed us not only to describe the spin-crossover for both polymorphs but also to reach phase-diagram regions where both polymorphs co-exist in different spin-states. Finally, the reversibility of the structural variations has been demonstrated.
authors.affiliation: LUNAM Université, Université de Nantes-Ecole Centrale Nantes, Institut de Recherche en Génie Civil et Mécanique UMR CNRS 6183, Equipe Etat Mécanique et Microstructure, Saint-Nazaire, France. vincent.legrand@univ-nantes.fr
authors.forename: Vincent
authors.initials: V
authors.lastname: Legrand
authors.forename: Stanislav
authors.initials: S
authors.lastname: Pechev
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Létard
authors.forename: Philippe
authors.initials: P
authors.lastname: Guionneau