•Novel Fe-La-B-based glass forming alloys with good magnetocaloric response near the ambient temperature were achieved in this work;•The GFA and MCE of the Fe88La7B5 glass forming alloy were ...significantly improved by 2% (at. %) addition of Ce;•The Fe86La7B5Ce2 amorphous ribbon show almost the highest magnetic entropy change near 313 K among the Fe-based metallic glasses.
Novel Fe-La-B-based glass forming alloys with better magnetocaloric response near the ambient temperature were achieved in this work. We firstly prepared the Fe88La7B5 glassy alloy with a Curie temperature (Tc) of about 329 K. However, the formability of the ternary metallic glass is very poor and the magnetic measurement on the Fe88La7B5 glassy ribbon indicates that the ribbon may be not fully amorphous. By adding 2% (at. %) Ce, we successfully fabricated Fe86La7B5Ce2 amorphous ribbon with enhanced glass formability, decreased Tc (∼313 K) and better magnetocaloric effect. The magnetocaloric behaviors of the quaternary glassy ribbon were studied and the (ΔTad) was obtained. The high values of magnetic entropy change and adiabatic temperature rise near 313 K indicate that the Fe86La7B5Ce2 metallic glass can be used as an optimal magnetic refrigerant component working at the hot end of a domestic refrigerator.
•Monte Carlo simulation has been performed to study the magnetocaloric properties of Sr2CrIrO6.•Magnetic entropy change, adiabatic temperature change and relative cooling power have been ...calculated.•The hysteresis loops of the system are examined as a function of the model parameters.
The hysteresis behavior and the magnetocaloric properties of the double perovskite (DP) Sr2CrIrO6 near the first and second-order phase transitions have been studied using the Monte Carlo simulations based on the heath bath algorithm. We have investigated the magnetic behavior of the system as a function of the temperature. The amplitude of the total susceptibility and the specific heat peaks increase by increasing the values of the magnetic field h. The magnetic entropy change ΔSm, the adiabatic temperature change ΔTad are obtained for different external magnetic fields and temperatures. It is found that the system exhibits an inverse magnetocaloric effect when we have a ferrimagnetic interaction between the two sublattices. The relative cooling power (RCP) increases with increasing the external magnetic field and decreases with the temperature. The hysteresis loops of the system are examined as a function of the Hamiltonian parameters the result obtained show that the system may display various hysteresis behaviors such triple, double, single loop and step-like loops.
Mn2−xCrxSb exhibits an antiferromagnetic-ferrimagnetic transition of which the temperature can be adjusted by the Cr concentration. The transition temperature is at room temperature for x = 0.13, but ...an additional ferromagnetic MnSb impurity phase is usually inevitable at this concentration. To suppress the occurrence of this phase unfavorable for the magnetocaloric effect, we partially replace Sb by Ga. We show that Mn2−xCrxSb0.95Ga0.05 alloys have a narrow transitional hysteresis and exhibit the inverse magnetocaloric effect. We present here results on structural, magnetic, and magnetocaloric properties using isothermal magnetization and direct adiabatic temperature-change measurements. We find in particular for the sample with x = 0.13 a nearly hysteresis-free transition with a 2 K temperature-change around room temperature making it attractive for magnetic cooling technology.
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Improving the elastocaloric effect (eCE) under a low stress by microstructure design is critical for the realization of eCE based solid-state cooling technology. Herein, we demonstrate a nearly ...seven-fold enhancement of adiabatic temperature change (ΔTad) and a large operating temperature window (WT), by simply introducing microstructural holes into a polycrystal shape memory alloy via phase-field simulations. At a low external compressive stress of 170 MPa, ΔTad is increased from 1 to 7.1 K and WT is 9 K when a microstructural hole with a radius of 200 nm is introduced. It is found that under such a low external compressive stress, the local stress concentration induced by the hole initiates and promotes the austenite-martensite transformation that otherwise cannot occur in the sample without a microstructural hole, and thus is responsible for the giant enhancement of ΔTad. These findings would provide guidance to improve low-stress eCE by microstructural geometry design.
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•Giant low-stress elastocaloric effect is achieved by microstructural geometry design.•A microstructural hole of 200 nm radius induces seven-fold enhancement of adiabatic temperature change.•A microstructural hole of 200 nm radius increases the operating temperature window to 9 K.•At a stress of 170 MPa, adiabatic temperature change is increased to 7.1 K by a microstructural hole.•Microstructural hole induced local stress concentration is responsible for the giant enhancement.
We report the magnetic and magnetocaloric properties of rapidly solidified Ni0.895Cr0.105MnGe1.05 melt-spun ribbons studied by both direct (adiabatic temperature change) and indirect (isothermal ...magnetic entropy change) methods in intermediate and high magnetic fields up to 10 T. The maximum values of the adiabatic temperature changes (ΔTad) and magnetic entropy changes ( Δ S M ) were found to be ~2.6 K (µoH = 10 T) and 4.4 J kg-1 K-1 (µoΔH = 5 T), respectively, near the Curie temperature (TC). The ΔTad curves and magnetization isotherms were found to be completely reversible, which indicates the high degree of reversibility of the MCEs in this system. A large temperature span (of about 61 K) and a non-saturating behavior of ΔTad were observed at magnetic fields up to 10 T. The adiabatic temperature change was found to be a linear function of (µoH)2/3 near TC, in accordance with the Landau theory of phase transitions.
Solid-state elastocaloric cooling based on elastocaloric effect resulting from superelastic martensitic transformation has been conceived as a very competitive alternative to the conventional ...vapor-compression refrigeration. Reducing the driving stress of elastocaloric effect is very beneficial to the miniaturization and compactness of refrigeration devices. Here, we demonstrate large elastocaloric effect driven by low stress in a directionally solidified Ni50Mn33In15.5Cu1.5 alloy. Owing to the coarse columnar shaped grains with strong A preferred orientation, large adiabatic temperature change (ΔTad) values up to −9.5 K and −11.4 K can be achieved on removing the relatively low compressive stress of 113 MPa and 150 MPa, respectively, showing the high sensitivity of elastocaloric response with the specific adiabatic temperature change (|ΔTad/σmax|) up to 83.5 K/GPa. Such value is much higher than those in other Ni–Mn-X based alloys reported previously.
• A textured Ni50Mn33In15.5Cu1.5 alloy prepared by directional solidification.•Reversible compressive strain of 7.5% obtained through superelastic martensitic transformation.•Adiabatic temperature change of −11.4 K achieved on unloading at the strain of 7%.•Specific adiabatic temperature change can be as large as 83.5 K/GPa.
2D magnets can potentially revolutionize information technology, but their potential application to cooling technology and magnetocaloric effect (MCE) in a material down to the monolayer limit remain ...unexplored. Herein, it is revealed through multiscale calculations the existence of giant MCE and its strain tunability in monolayer magnets such as CrX
(X = F, Cl, Br, I), CrAX (A = O, S, Se; X = F, Cl, Br, I), and Fe
GeTe
. The maximum adiabatic temperature change (
), maximum isothermal magnetic entropy change, and specific cooling power in monolayer CrF
are found as high as 11 K, 35 µJ m
K
, and 3.5 nW cm
under a magnetic field of 5 T, respectively. A 2% biaxial and 5% a-axis uniaxial compressive strain can remarkably increase
of CrCl
and CrOF by 230% and 37% (up to 15.3 and 6.0 K), respectively. It is found that large net magnetic moment per unit area favors improved MCE. These findings advocate the giant-MCE monolayer magnets, opening new opportunities for magnetic cooling at nanoscale.
We report the magnetocaloric properties of two Fe-containing quinary bulk polycrystalline alloys of nominal compositions Ni41Co7Fe2Mn40Sn10 and Ni41Co6.5Fe2.5Mn40Sn10 that were determined by indirect ...and direct methods. Both samples showed a large refrigeration capacity RC and maximum magnetic entropy change ΔSMpeak around room temperature. For a magnetic field change of 2 T (5 T), a large magnetic entropy change of 18.9 (22.4) J kg−1 K−1 and 11.8 (16.8) J kg−1 K−1 and a refrigeration capacity of 128 (396) J kg−1 and 99 (313) J kg−1 were found in Ni41Co7Fe2Mn40Sn10 and Ni41Co6.5Fe2.5Mn40Sn10 alloys, respectively. RC for the alloy Ni41Co7Fe2Mn40Sn10, is among the largest value reported so far for Ni–Mn based Heusler alloys. Under a 1.5 T field change, the direct measurements showed the maximum adiabatic temperature changes ΔTadmax of −0.8 K and −1.5 K for these two alloys, respectively. The present findings point out the potential of Fe-alloyed Ni41Co9Mn40Sn10 Heusler alloys as room-temperature magnetic refrigerants.
•Ni41Co9-xFexMn40Sn10 alloys (x = 2.0 and 2.5) possess an excellent magnetocaloric effect near room temperature.•Refrigeration capacity of Ni41Co7Fe2Mn40Sn10 is among the largest value reported so far for Ni–Mn based Heusler alloys.•Ni41Co9-xFexMn40Sn10 alloys (x = 2.0 and 2.5) demonstrate their potential as room-temperature magnetic refrigerants.
The relaxation processes of the adiabatic temperature changes (ΔTad) at the phase transitions in Ni45Mn43CoSn11, Ni50Mn36.5In13.5, and Ni50Mn35In14.25B0.75 Heusler alloys with different magnetic ...structures have been studied using a direct extraction method in magnetic fields up to 14 T. It has been found that ΔTad exhibits short relaxation times (less than 10–1 (s)) in the vicinity of the second order phase transitions at the Curie temperatures. Furthermore, the relaxation times of the first order martensitic transitions strongly depend on the latent heat of the transition and can be characterized by a logarithmic law.
In the present work, a low-pressure-induced large reversible barocaloric effect was achieved in (MnNiGe)0.91-(FeCoGe)0.09 alloys. The isothermal entropy change and the adiabatic temperature change ...are as high as 32.8 J·kg−1K−1 and 5.2 K by applying hydrostatic pressure of 1 kbar, respectively. The reversible isothermal entropy change of 19.3 J·kg−1K−1 and reversible adiabatic temperature change of 3.6 K within a temperature span of 16 K at 1 kbar have been achieved. Good reversible barocaloric performance is attributed to the combination of the thermal hysteresis of 6.4 K and the transition temperature shift with the pressure of 6.9 K·kbar−1.
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