Elastocaloric, barocaloric and magnetocaloric effects in spin crossover polymer composite films.

Giant barocaloric effects were recently reported for spin-crossover materials. The volume change in these materials suggests that the transition can be influenced by uniaxial stress, and give rise to giant elastocaloric properties. However, no measurements of the elastocaloric properties in these compounds have been reported so far.

Tuning of the magneto-caloric effects in NiMnInmagnetic shape memory alloys by substitution of boron.

In this study, we report the structural, magnetic, and magnetocaloric properties of B substitution on the Mn site in NiMnBIn(= 0.5, 1.0) Heusler alloys.

Some Nitrogen Rich Energetic Material Synthesis by Nucleophilic Substitution Reaction from Polynitro Aromatic Compounds.

Three new nitrogen-rich energetic compounds, N-(5-chloro-2,4-dinitrophenyl)hydrazine (1), N-(5-chloro-2,4-dinitrophenyl)guanidine (2) and N-(5-chloro-2,4-dinitrophenyl)-4-aminopyrazole (3) prepared by the nucleophilic substitution reaction of 1,3-dichloro-4,6-dinitrobenzene with hydrazine, guanidinium carbonate and 4-aminopyrazole. The compounds were characterized by 1H NMR, 13C NMR, IR and mass spectroscopy. Only compound 2 could be prepared in a suitable crystal and molecular model was determined by X-ray analysis.

Giant and Reversible Barocaloric Effect in Trinuclear Spin-Crossover Complex Fe (bntrz) (tcnset).

A giant barocaloric effect (BCE) in a molecular material Fe (bntrz) (tcnset) (FBT) is reported, where bntrz = 4-(benzyl)-1,2,4-triazole and tcnset = 1,1,3,3-tetracyano-2-thioethylepropenide. The crystal structure of FBT contains a trinuclear transition metal complex that undergoes an abrupt spin-state switching between the state in which all three Fe centers are in the high-spin (S = 2) electronic configuration and the state in which all of them are in the low-spin (S = 0) configuration. Despite the strongly cooperative nature of the spin transition, it proceeds with a negligible hysteresis and a large volumetric change, suggesting that FBT should be a good candidate for producing a large BCE.