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• Spin reorientation vanishes at a high magnetic field for a TmFeO 3 single crystal. • Evidence of magneto-structural coupling in the TmFeO 3 single crystal is provided. • Spin reorientation shifts and widens under hydrostatic pressure. • Widening of spin reorientation transition is attributed to an intermediate phase. We report the growth of a TmFeO 3 single crystal, its magnetic and structural properties upon varying temperature, magnetic field, and hydrostatic pressure. The abrupt change related to the spin reorientation (SR) process vanishes under a 30 kOe magnetic field in both thermomagnetic and strain curves, indicating strong magneto-structural coupling in such orthoferrite. Interestingly, the thermomagnetic curve under hydrostatic pressure reveals that the SR shifts towards higher temperatures and its temperature interval widens upon the application of external hydrostatic pressure. Combining the strain data obtained under similar conditions, the onset temperature shift of SR is concluded to originate from changes in structural parameters and widening of the SR transition is attributed to the presence of an intermediate phase. These findings may shed light on the envisage of potential uses in magneto-mechanical and transducer devices, based on the interaction between structure and magnetism. [ABSTRACT FROM AUTHOR]

The structure, transition properties, and hydrostatic pressure (p) and magnetic field (B) dependence of transition temperatures and operation-temperature window (Δ T , defined as the temperature range of martensitic transition) were investigated in Ni 53 Mn 21 Ga 26 alloy. The results reveal that all the transition temperatures and Δ T increase almost linearly with increasing magnetic field and pressure. Particularly, a stronger dependence of peak temperature (T M) and Δ T on pressure, d T M /d p = 25.7 K/GPa and dΔ T /d p = 18.7–22.7 K/GPa, is observed in contrast with the smaller values of d T M /d B = 1.3 K/T and dΔ T /d B = 1.4–1.7 K/T found in Ni 53 Mn 21 Ga 26 alloy. Furthermore, the value of 25.7 K/GPa may be the largest shift in T M with pressure observed in polycrystalline Ni–Mn-Ga systems. Clearly, the sensitivities of T M and Δ T to pressure are much higher than those to magnetic field. These findings illustrate that applying hydrostatic pressure is beneficial to broaden Δ T in Ni 53 Mn 21 Ga 26 alloy. • Ni 53 Mn 21 Ga 26 alloy exhibits a magnetostructural transformation (MST). • Hydrostatic pressure effects on the phase transition properties and operation-temperature window (Δ T) have been studied. • A large shift in peak temperature with pressure of 25.7 K/GPa was observed. • A strong response of Δ T to pressure p , dΔ T /d p = 18.7–22.7 K/GPa, was reported. • Hydrostatic pressure can effectively broaden the operation-temperature window. [ABSTRACT FROM AUTHOR]

The structural, magnetic, magnetocaloric and barocaloric properties were investigated in Ni 55.5 Mn 17.8 Ga 26.7 alloy. The results show that the sample experiences two successive magnetostructural transformations (MSTs) with decreasing/increasing temperature. The field-induced entropy change and pressure-induced entropy change are only −7.55 J/kg K for a field change of Δ H = 3 T and −10.52 J/kg K for a pressure change of Δ P = 0.622 GPa while the corresponding refrigeration capacity (RC) achieves 68.80 J/kg and 247.83 J/kg, respectively. Such considerable RC values can be ascribed to the broadening of the full-width at half maximum (FWHM) due to the two successive MSTs. It was observed that RC and FWHM increase with magnetic field and pressure, which results in an enhancement of magnetocaloric and barocaloric effects. Importantly, RC and FWHM under Δ P = 0.622 GPa are comparable to and even larger than those reported in some expensive rare-earth-based magnetic refrigerants. The responses of RC and FWHM to pressure are 89.05 J/kg GPa and 4.77 K/GPa for 0 ≤ P ≤ 0.3 GPa and the values are 654.57 J/kg GPa and 73.86 K/GPa for 0.3 ≤ P ≤ 0.622 GPa. The FWHMs of 11.23 K under Δ H = 3 T and of 32.83 K under Δ P = 0.622 GPa are obtained. All these excellent properties originated from two successive MSTs would make Ni 55.5 Mn 17.8 Ga 26.7 alloy promising as a new and inexpensive multicaloric material used in the solid refrigeration technology. • Ni 55.5 Mn 17.8 Ga 26.7 alloy exhibits two successive magnetostructural transformations (MSTs). • Large magnetocaloric and barocaloric effects were observed due to the two successive MSTs. • Two successive MSTs and hydrostatic pressure can effectively broaden the phase transforming temperature span. • A large refrigerant capacity of 247.83 J/kg was obtained under a pressure change of 0.622 GPa. • An inexpensive multicaloric material Ni 55.5 Mn 17.8 Ga 26.7 alloy was reported. [ABSTRACT FROM AUTHOR]