Critical behaviour 1 Dynamic studies 1 Ferromagnetic spin model 1 Hamiltonians 1 Interaction ranges 1 Molecular dynamics 1 Neighbor spin 1 One-dimensional 1 Order parameter 1 Phase transitions 1 Spin chains 1 Spin dynamics 1 Transition phase 1 Variable interaction 1 density functional theory 1 interaction range 1 magnetic specific heat 1 molecular dynamics 1 neighbours spins 1 phonon density of states 1 quasi-one-dimensional antiferromagnet 1 spin chain models 1 ternary potassium-iron sulfide 1 transition phase 1