Süheyla Yüce

Barocaloric effect in the magnetocaloric prototype Gd5Si2Ge2

We report on calorimetric measurements under hydrostatic pressure that enabled us to determine the barocaloric effect in Gd5Si2Ge2. The values for the entropy change for moderate pressures compare favourably to those corresponding to the magnetocaloric effect in this compound. Entropy data are complemented with direct measurements of the adiabatic pressure-induced temperature change.

Large reversible entropy change at the inverse magnetocaloric effect in Ni-Co-Mn-Ga-In magnetic shape memory alloys

Calorimetry under magnetic field has been used to study the inverse magnetocaloric effect in Ni-Co-Mn-Ga-In magnetic shape memory alloys. It is shown that the energy dissipated during a complete transformation loop only represents a small fraction (5% to 7%) of the latent heat of the martensitic transition. It is found that the entropy values obtained from isofield temperature scans agree well with those obtained from isothermal magnetic field scans. The reproducibility of the magnetocaloric effect has been studied from isothermal measurements. Reproducible entropy values under field cycling have been found within a temperature interval bounded by the start temperature of the forward transition at zero field and the start temperature of the reverse transition under applied field. Large reversible entropy changes around 11 J/kg K have been found for fields up to 6 T.

Accessibility investigation of large magnetic entropy change in CoMn1−xFexGe

The influence of Fe doping for Mn in CoMn1−xFexGe alloys on their structural and magnetic phase transitions was investigated. CoMn1−xFexGe alloys display a first-order magneto-structural transition from a high temperature paramagnetic hexagonal Ni2In-type crystal structure to a low temperature ferromagnetic orthorhombic TiNiSi-type structure. An entropy change of ΔSM = −32.8 J/kg K was measured and adiabatic temperature change of −8.0 K was computed for the x = 0.085 alloy under a magnetic field of 7 T in the vicinity of the phase transition at 317 K. With increasing Fe content, transition temperatures and magnetic entropy changes decrease. In addition to investigating the effect of replacing Mn with Fe, the accessibility of the giant measured entropy change was quantified by means of the minimum magnetic field required to start and to complete the magneto-structural phase transition.

1-((4-Acetylphenylamino)methylene)naphthalen-2(1H)-one

The molecule of the title compound, C19H15NO2, is nearly planar and adopts the keto–amine tautomeric form, with a strong intramolecular N—H⋯O [2.5383 (17) A] hydrogen bond.