Maximum Magnetic Entropy Research Articles

An assessment of the mechanically alloyed equiatomic FeCoNiMnSi high entropy amorphous alloy for non-isothermal crystallization kinetics and magnetocaloric refrigeration application

We studied an equiatomic FeCoNiMnSi high entropy amorphous alloy successfully processed via mechanical alloying technique. The structural, magnetic, and magnetocaloric characteristics of the resulting materials were examined using X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and a vibrating sample magnetometer. The structural analysis showed a prominent amorphous phase formation as the milling time increases from t = 0–35h of mechanical alloying. The differential scanning calorimetry was employed to investigate the non-isothermal crystallization kinetics of the 35-h milled sample. The results revealed that the milled powder consists of a single exothermic peak with its apparent activation energy (Eg, Ex, Ep) being determined using the Kissinger, Ozawa, and Augis-Bennett equations. The findings exhibit Ex > Ep > Eg, representing that nucleation is more complicated than the growth mechanism during the crystallization process. Meanwhile, under non-isothermal conditions, the Kissinger-Akahira-Sunose, Friedman, and Flynn-Wall-Ozawa models were calculated using the local activation energies that agree with the apparent activation energy. Furthermore, the Johson-Mehl-Avrami-Kolmogorov exponent (n) and Avrami-Ozawa combined [F(T)] models exhibit high-dimensional nucleation and growth with an increasing nucleation rate enabled by lowering the local activation energies as a function of degree of conversion with respect to temperature. In magnetic measurements, a feasible mathematical model was proposed as a novel strategy for predicting the value of saturation magnetization as a milling time function. The model has an exceptional predictive capability, confirmed by fitting other research outcomes. Finally, the proposed system also delivers the best magnetocaloric properties with a maximum magnetic entropy change of 3.70 Jkg−1 K−1 at 150 K curie temperature and a refrigeration capacity of 252.86 J/kg with 1000 Oe applied magnetic field.

Investigation of the effect of martensitic phase transition temperature and Curie temperature difference on magnetic and magnetocaloric properties under low magnetic field on Si-doped Ni-Mn-In Heusler alloys

This study examines the impact of substituting Si for Mn on the structural, magnetic, and magnetocaloric properties of Ni43Mn46−x Si x In11 (x = 0.3 and 0.6) alloys. To this end, a range of analytical techniques are employed, including scanning electron microscopy (SEM), room temperature x-ray powder diffraction (XRD), and magnetization measurements. Above the martensitic transition temperature, the Ni43Mn46−x Si x In11 alloys exhibit cubic L2 1 (space group FM-3M). Below this temperature they adopt a tetragonal L1 0 (space group I4/mmm). The martensitic transition temperature decreased when Si is substituted for Mn. The magnetic field-induced entropy change is calculated from magnetic field-dependent magnetization measurements using Maxwell’s equations. The maximum magnetic field-induced entropy changes for Ni43.16Mn45.56Si0.29In11 and Ni43.51Mn44.82Si0.59In11 alloys are calculated 8.20 J kg−1K−1 and 3.15 J kg−1 K−1, respectively, in the vicinity of the magnetostructural phase transition for a magnetic field change of 18 kOe. It is demonstrated that the temperature differential between the high-temperature austenite phase's Curie point (T C ) and the mean martensitic transformation temperature (T M ), namely (T M -T C ), influences the martensitic transition temperatures and, consequently, on the magnetic field-induced entropy change (ΔS M ).

Enhanced magnetocaloric and cold storage properties in HoCu2-xNix (x=0.05–0.5) compounds for hydrogen liquefaction

Based on first-principle calculations and experiments, the electronic structure, magnetism, magnetocaloric effect and cold storage properties of HoCu2-xNix (x=0.05–0.5) compounds have been investigated. The theoretical calculations revealed that the magnetic interactions of the HoCu2-xNix compounds were gradually transformed to ferromagnetic states when the Ni element was added above 0.0625. In addition, the Ni element leads to a decreasing Fermi energy level, which results in a significant enhancement of orbital hybridization around the Fermi surface, which may be responsible for the magnetic jump. The magnetic phase transition temperatures of the HoCu1.75Ni0.25 and HoCu1.5Ni0.5 compounds are 14.4 K and 26.0 K, respectively. The ferromagnetic state transition is responsible for the excellent magnetocaloric effect of the HoCu2-xNix compounds under low magnetic fields. The maximum magnetic entropy changes of the HoCu1.75Ni0.25 and HoCu1.5Ni0.5 compounds were 14.7 J/kg K and 11.5 J/kg under varying magnetic fields from 0 to 2 T. In addition, the Ni element make the HoCu2 compound exhibit more excellent cold storage capability. The peak of specific heat capacities of HoCu1.75Ni0.25 and HoCu1.5Ni0.5 compounds were 0.6 J/cm−3K−1 and 0.9 J/cm−3K−1 under 0 T. The present results indicate that HoCu2-xNix (x=0.05–0.5) compounds have promising applications in cryogenic cold storage and magnetic refrigeration.

Magnetocaloric Properties of Melt-Extracted Medium Entropy Gd33Co33Al34 Microfibers

In this paper, a new medium entropy alloy with nominal composition of Gd33Co33Al34 was designed and fabricated into microfibers by a melt-extraction method. The microstructure, thermophysical parameters, and magnetocaloric properties of the obtained fibers were systematically analyzed. The results showed that the as-cast fibers show an amorphous matrix with embedded in situ nano crystals. The fibers show a good magnetocaloric effect with the maximum magnetic entropy change of ~6 J/kg·K for a field change of 5 T. Notably, the fibers show excellent cooling efficiencies with an RCP and RC of ~611.72 and ~487.38 J/kg, respectively. Though the as-cast fibers possess an amorphous/nanocrystal bi-phase structure, they still exhibit a second-order transition near a Curie temperature of ~96 K. Our findings provide a promising pathway towards developing new magnetocaloric materials with good magnetocaloric performances.

Cryogenic temperature magnetocaloric effect and critical behavior of GdDyErAlM (M=Fe, Co, Ni) high entropy amorphous alloys

High entropy amorphous alloys (HE AMs) have attracted extensive interest lately due to their superior magnetocaloric properties. However, the critical behavior and mechanical properties have received less research, which restricts their applications. This work presented a comprehensive investigation of the magnetocaloric effect (MCE), critical behavior, and mechanical performance of quinary Gd20Dy20Er20Al20M20 (M = Fe, Co, Ni) HE AMs. All samples exhibited distinct spin glass-like behavior below TC and competitive MCE around hydrogen liquefaction temperature range. Excellent MCE was achieved by the HE AMs through a second-order phase transition from paramagnetic state to ferromagnetic state at 79 K for Fe, 41 K for Co, and 36 K for Ni. Among them, the maximum magnetic entropy change (-ΔSM)max of Gd20Dy20Er20Al20Co20 amorphous alloys was 9.59 J kg−1 K−1 under 0–5 T. Furthermore, RC and RCP of Gd20Dy20Er20Al20Fe20 amorphous alloys were respectively 519 J kg−1 and 613 J kg−1, larger than that of most RE-based amorphous alloys. For all samples, the critical behavior of the phase transition approached the mean field model, and this responded to the long-range ordering of the magnetic interaction. The bending plasticity of Gd20Dy20Er20Al20M20 (M = Fe, Co, Ni) HE AMs were 0.78, 1.03, 0.89, respectively. The adjustable Tc, large (-ΔSM), high RCP, and outstanding mechanical properties suggested Gd20Dy20Er20Al20M20 (M = Fe, Co, Ni) HE AMs may find utility as magnetic refrigerants in low-temperature applications.

Effect of Annealing Temperature on Microstructure and Magnetocaloric Properties of Gd-Based Metallic Microfibers

In this paper, vacuum annealing has been adopted to introduce atomic cluster micro-regions inside Gd-based metallic microfibers to further explore the effect of the structural changes on the magnetocaloric properties and the mechanism which is systematically expressed. The experimental results indicate that the as-prepared Gd-based metallic microfibers have favorable amorphous formation ability and thermal stability. After annealing @ 380 °C, the maximum magnetic entropy change −ΔSmmax, refrigerating capacity (RC), and relative cooling power (RCP) values of the Gd-based metallic microfibers are 7.20 J/kg·K, 459.4 J/kg, and 588.7 J/kg, respectively. Combined with the transmission electron microscopy analysis results, the internal organizational order of the annealed microfibers is significantly altered, and the atomic clusters formed in localized regions, which reduce the magnetocrystalline anisotropy of the microfibers. While under the uni-action of an external magnetic field, the magnetic moment rotation state and magnetic domain structure distribution of the micro-region atoms will be changed obviously, thereby changing the general magnetic properties and magnetocaloric properties of the metallic microfibers. The above research results can promote the engineering application of Gd-based metallic microfibers in the field of magnetic refrigeration.

Magnetocaloric effect and phase transformation of Zn-doped Ni–Mn–Ti all-d metal Heusler alloys

Ni–Mn–Ti Heusler alloys have gained a great consideration recently due to their important magnetoresistance and magnetocaloric properties. Herein, the structure, martensitic transition (MT), and magnetocaloric effect (MCE) of Ni50-xZnxMn35Ti15 (x = 0, 2, 4, and 6) Heusler alloys have been studied. XRD results show that the studied alloy with x = 0 display a monoclinic (5 M) martensite phase. Besides, the examined alloy with x = 2 presents a combination of monoclinic (5 M) martensite and cubic (B2) austenite phases, whereas the alloys with x = 4 and x = 6 exhibit only a cubic (B2) austenite phase. By increasing Zn content x up to 6, the Curie temperature of austenite decreases from 283 K to 132 K, and the MT temperatures decrease from ferromagnetic austenite to weak-magnetic martensite, which is apparently due to the exchange interaction of Mn–Mn and the low power of d-d hybridization between the A/C and B(D) sites. The best maximum magnetic entropy change (ΔSM, max) and refrigeration capacity (RC) are for the studied alloy with x = 4 (5.22 J kg−1K−1 and 217 J kg−1 at 120 kOe, respectively). The Zn addition not only facilitates the formation of B2-type Heusler phases but also offer the possibility to tune the MT and establish strong ferromagnetic coupling.

Enhanced Cryogenic Magnetocaloric Effect from 4f‐3d Exchange Interaction in B‐Site Ordered Gd2CuTiO6 Double Perovskite Oxide

AbstractMagnetic refrigeration based on the principle of the magnetocaloric effect (MCE) in magnetic solids has been considered as a prospective cooling technology. Exploring suitable magnetocaloric materials (MCMs) is a vital prerequisite for practical applications. Herein, an excellent cryogenic MCM—the B‐site‐ordered Gd2CuTiO6 double perovskite (DP) oxide—which exhibits the largest MCE among known Gd‐based DP oxides, is identified. Such enhanced cryogenic MCE in the Gd2CuTiO6 DP oxide likely stems from the exchange interaction effect between Gd‐4f and Cu‐3d magnetic sublattices. Under a magnetic field change of 0–7 T, the maximum magnetic entropy change (−ΔSTmax) of the Gd2CuTiO6 DP oxide reaches 51.4 J kg−1 K−1 (378.2 mJ cm−3 K−1), which is much larger than that of the commercialized magnetic refrigerant Gd3Ga5O12, which is 38.3 J kg−1 K−1 (271.2 mJ cm−3 K−1), and it is also superior to most of the recently reported benchmarked cryogenic MCMs, indicating the possibility for practical applications. This work also provides a productive route for future cryogenic MCM design by harnessing 4f–3d exchange interactions.

Large magnetocaloric refrigeration performance near room temperature in monolayer transition metal dihalides

Magnetocaloric effect (MCE) exhibits highly efficient and ecological cooling abilities for solid-state refrigeration in contrast to traditional vapor-compression refrigeration. Successive emerging two-dimensional (2D) magnetic materials provide a fertile platform for exploring low-dimensional MCE systems. Here, we focus on a series of 2D transition metal dihalides MX2 (M = Fe, Ru, Os; X = Cl, Br) to explore the maximum isothermal magnetic entropy change (−ΔSmagmax) and adiabatic temperature change (ΔTadmax) under external magnetic field. It is found that FeCl2, FeBr2, and RuCl2 have intrinsically sizable −ΔSmagmax, ΔTadmax, and high thermal conductivity near room temperature, demonstrating superior comprehensive refrigeration performance in comparison with other 2D magnets. It is revealed that strong nearest-neighbor ferromagnetic exchange interaction plays a decisive role in −ΔSmagmax, and the high lattice thermal conductivities of FeCl2 and RuCl2 are attributed to the longer phonon lifetime and larger group velocity of low-frequency acoustic branch. Moreover, moderate strain and carriers doping are able to effectively regulate Curie temperature and magnetocrystalline anisotropy energy and correspondingly enhance −ΔSmagmax. The present work provides important insights for the exploration of 2D magnets for magnetocaloric refrigeration near room temperature.

Synthesis, Structure, and Magnetic Properties of Cyanurates RE5(C3N3O3)(OH)12 (RE = Gd-Lu): Cryogenic Magnetocaloric Candidate Gd5(C3N3O3)(OH)12.

Rare-earth (RE)-based frustrated magnets are fertile playgrounds for discovering exotic quantum phenomena and exploring adiabatic demagnetization refrigeration applications. Here, we report the synthesis, structure, and magnetic properties of a family of rare-earth cyanurates RE5(C3N3O3)(OH)12 (RE = Gd-Lu) with an acentric space group P6̅2m. Magnetic susceptibility χ(T) and isothermal magnetization M(H) measurements manifest that RE5(C3N3O3)(OH)12 (RE = Gd, Dy-Yb) compounds exhibit no magnetic ordering down to 2 K, while Tb5(C3N3O3)(OH)12 shows long-range magnetic ordering around 3.6 K. Among them, magnetically frustrated spin-7/2 Gd5(C3N3O3)(OH)12 shows long-range magnetic ordering around 1.25 K and a large magnetocaloric effect with a maximum magnetic entropy change ΔSm of up to 58.1 J kg-1 K-1 at ΔH = 7 T at liquid-helium temperature regimes.

Mechanically strong and room-temperature magnetocaloric monolayer VSi2N4 semiconductor

In the realm of emerging two-dimensional MoSi2N4 family, the majority of research endeavors gravitate toward their versatile physical properties, while their magnetocaloric effect (MCE) for the potential refrigeration application remains uncharted. Here, we comprehensively explore the magnetic, electronic, mechanical, and magnetocaloric properties of monolayer VA2Z4 (A = Si, Ge; Z = N, P, As) family by multiscale simulations, revealing that monolayer VSi2N4 semiconductor is mechanically strong and exhibits room-temperature MCE. The nonlinear elastic response of VSi2N4 unveils strong mechanical properties, featuring a substantial in-plane Young's modulus (E2D∼ 350 N/m) and a high strength of 40.8 N/m, comparable to that of graphene. Monolayer VSi2N4 exhibits a room-temperature MCE with an extensive refrigeration temperature range up to 20 K. Furthermore, applying biaxial strain can significantly improve the maximum magnetic entropy change (−ΔSMmax) and maximum adiabatic temperature change (ΔTadmax) by 80.9% and 197.3%, respectively. Room-temperature MCE with wide working temperature and mechanical robustness make monolayer VSi2N4 an appealing candidate for magnetic refrigeration applications over large temperature range. These findings offer fresh insights for advancing the development of magnetic cooling in small-sized systems.

Direct and inverse magnetocaloric effects in magnetostrictive GdMn2Ge2 with field-induced metamagnetic transition

Heavy rare-earth-based ternary intermetallic compounds with the formula RT2X2 have drawn great interest because of their multiple magnetic transitions and various magnetic structures. Here, anisotropic magnetic behaviors, magnetocaloric effects (MCEs), and magnetostriction effects in single-crystalline GdMn2Ge2 are studied in two different directions. Experiments show a magnetic transition characterized by a sudden decrease in magnetization for μ0H//a and a sharp increase for μ0H//c at Tt. The transition is driven by lower temperatures for μ0H//a, contrasting that for μ0H//c with an increase in the magnetic field. An inverse MCE is observed for μ0H//a with a maximum magnetic entropy change (−ΔSMmax) of −7.4 J kg−1 K−1 (μ0ΔH = 6 T), while a direct MCE is obtained for μ0H//c with an −ΔSMmax of 8.0 J kg−1 K−1 under the same magnetic field change. Moreover, a remarkable field-induced metamagnetic transition and a magnetostriction effect are observed simultaneously at Tt, indicating strong magneto-lattice coupling. The T-μ0H phase diagrams are constructed based on the magnetic properties. The coexistence of direct and inverse MCEs is discussed and is due to the spin-flop of Mn and anisotropic magnetic properties under magnetic fields in different directions.

Magnetocaloric effect in kagome MgMn6Sn6

We have studied magnetocaloric effect of kagome MgMn6Sn6 single crystal. The MgMn6Sn6 single crystal exhibits a typical transition of ferromagnetic (FM) to paramagnetic (PM). Maximum magnetic entropy change (−ΔSMmax) and relative cooling power (RCP) for a field change of 0–50 kOe were calculated to be 3.05 J/kg K and 129 J/kg for H//ab, 2.76 J/kg K and 115 J/kg for H//c, respectively. Concurrently, around the phase transition temperature TC, the scaling approach for MgMn6Sn6 is used to study the magnetic entropy change [ΔSM(T,H)]. The outcome suggests that, in the presence of high field, the curves of ΔSM(T,H) can be effectively combined to form a single, universal curve that is unaffected by temperature or external fields. Nevertheless, under low field, ΔSM(T,H) curves diverge slightly below TC, indicating a first-order transition feature. According to the scaling analysis of ΔSM(T,H) curves, the phase transition of MgMn6Sn6 is forced into a second-order one under high field conditions, even if in the low field zone, it is a weak first-order type. Furthermore, it is discovered that the observed magnetocaloric effect (MCE) in kagome MgMn6Sn6 could not be satisfactorily explained by a basic theoretical model that simply took into consideration the magnetoelastic and magneto electron coupling.

A novel Fe87Pr11B2 amorphous alloy with outstanding magnetocaloric properties near 325 K

A novel Fe87Pr11B2 metallic glass that exhibits outstanding magnetocaloric effect near room temperature was prepared into the shape of amorphous ribbons. The ribbon exhibits soft magnetic properties and high saturation magnetization at 200 K, which is much lower than its Curie temperature at 325 K. No obvious spin-glass-like behavior was found above 200 K. The almost highest maximum magnetic entropy change (−ΔSmpeak) among Fe-based metallic glasses near the hot end of a residential magnetic refrigerator is most likely attributed to the high concentration of Pr and low content of B in the Fe87Pr11B2 amorphous ribbon. The high −ΔSmpeak, large refrigeration capacity (RC) and adiabatic temperature rise (ΔTad) make the Fe87Pr11B2 amorphous alloy better candidate for the potential component of a refrigerant working in a high-efficiency residential magnetic refrigerator.

A Brilliant Magnetic Refrigerant Operating Near Liquid Helium Temperature: Enhanced Magnetocaloric Effect in Ferromagnetic EuTi0.75Al0.125Zr0.125O3

AbstractRare earth‐based perovskites have become an attractive research interest in the field of cryogenic magnetic refrigerants due to their unique advantages in practical applications. The remarkable magnetocaloric effect (MCE) renders EuTiO3 a potential magnetic refrigerant in the liquid helium temperature range. More impressively, the tunability between antiferromagnetism (AFM) and ferromagnetism (FM) provides the feasibility of tailoring the magnetism and enhancing the magnetocaloric performance. In this study, the magnetism of EuTi0.75Al0.125Zr0.125O3 is investigated in depth through first‐principles calculations and experimental methods. Both theoretical calculations and experimental results reveal that it exhibits significant ferromagnetism due to the AFM‐FM magnetic transition promoted by the co‐substitution of Al and Zr. Lattice expansion and altered electronic interactions are responsible for the FM behavior, which leads to a significant enhancement of the MCE. With the field change of 0−1 T, the peak values of magnetic entropy change (−ΔSM), refrigerating capacity (RC), and adiabatic temperature change (ΔTad) reach 18.9 J kg−1 K−1, 77.7 J kg−1, and 7.4 K, respectively. More surprisingly, the values of maximum magnetic entropy change () and maximum adiabatic temperature change for EuTi0.75Al0.125Zr0.125O3 reach 11.4 J kg−1 K−1 and 3.7 K under the field change of 0−0.5 T, respectively. The remarkable magnetocaloric performance proves it to be a brilliant magnetic refrigerant operating near liquid helium temperature.

Spontaneous resolution and magnetic properties of lanthanide metal organic frameworks based on oxydiacetate

Chiral lanthanide metal organic frameworks (Ln-MOFs) have become a kind of promising platform for developing various chiral functional materials. However, their members are still scarce up to now, especially those obtained from spontaneous resolution. In this work, two pairs of enantiomers of chiral Ln-MOFs, namely, [Ln2(oda)3(H2O)4]·2H2O [Ln = Dy (Λ-1 and Δ-1), Gd (Λ-2 and Δ-2); oda = oxydiacetate], have been prepared from an achiral H2oda ligand by spontaneous resolution. They display homochiral Λ- or Δ-configurational 2D grid-like frameworks in the absence of any chiral source, where four carboxylate groups of oda2− ligands within each [LnIII(oda)3]3− module link to adjacent four Ln ions either in a left- or right-handed fashions. Their homochirality was further confirmed by solid-state circular dichroism (CD) spectrum. Magnetic measurements revealed that Λ-1 exhibits field-induced dual-relaxation behavior of single-molecule magnet (SMM). The effective energy barrier (Ueff) and relaxation time (τ0) of slow relaxation (SR) process are 92.63 K and 1.49 × 10−12 s, respectively. Furthermore, Λ-2 was found to show magnetocaloric effect (MCE), with the maximum magnetic entropy change (−ΔSm) of 10.02 J kg−1 K−1 at 7.0 T and 2.0 K.

Magnetic phase transition and large cryogenic magnetocaloric effect in the gallides RE2Rh3Ga (RE = Gd, Dy, Ho, Er)

We herein provide an experimental investigation of the gallides RE2Rh3Ga (RE = Gd, Dy, Ho, Er) regarding their magnetic properties and magnetocaloric effect (MCE). All of these RE2Rh3Ga intermetallic compounds crystallized with the Mg2Ni3Si type structure, space group R–3 m and are ordered magnetically at low temperatures. Large reversible MCEs around their own ordering temperature were observed in all RE2Rh3Ga compounds and their magnetocaloric parameters including the maximum magnetic entropy change, refrigerant capacity, and temperature-averaged entropy change are comparable to those of some recently reported candidate materials with prominent performances, making them considerable for cryogenic MR applications.

Structure, magnetism and magnetocaloric properties in performance GdClWO4 compound

Rare earth elements possessing a diverse range of optical, electrical, and magnetic properties has attracted more attention. In the present work, GdClWO4 compound with monoclinic structure was prepared, the structure, magnetism and magnetocaloric effect (MCE) were investigated. The magnetic phase transition temperature (TN), magnetic ground state and maximum magnetic entropy change (−ΔSMmax) were derived from magnetization measurements. Both first principles calculation and experimental results suggest that the compound displays antiferromagnetic (AFM) interactions, with a magnetic transition occurring at 0.6 K, shifting from a paramagnetic (PM) state to an AFM state. The −ΔSMmax is up to 35.2 J kg−1 K−1 (205.9 mJ cm−3 K−1) for GdClWO4 at T = 1.3 K under a magnetic field change of 0–50 kOe. In particular, the volumetric magnetic entropy change still remains 83.1 mJ cm−3 K−1 at 0.5 K and μ0ΔH = 20 kOe, which is almost twice as much as that of commercial refrigerant Gd3Ga5O12 (GGG) under μ0ΔH = 20 kOe, establishing GdClWO4 compound as a potential candidate for cryogenic refrigeration applications.

Characterization of magnetic properties, including magnetocaloric effect, of RE5Pt2In4 (RE = Gd-Tm) compounds

The RE5Pt2In4 (RE = Gd-Tm) rare earth compounds have been investigated by means of X-ray diffraction (XRD) as well as by DC and AC magnetometric measurements. The compounds crystallize in an orthorhombic crystal structure of the Lu5Ni2In4-type (Pbam space group, No. 55). With decreasing temperature, the intermetallics undergo a transition from para- to ferro-/ferri- (RE = Gd, Tb, Ho, Er) or antiferromagnetic state (RE = Tm). In case of Dy5Pt2In4, the ferromagnetic state is reached through an intermediate antiferromagnetic order present in a limited temperature range. The critical temperatures of magnetic ordering range from 4.1 K (RE = Tm) up to 108 K (RE = Tb). For the majority of investigated compounds, a cascade of additional magnetic transitions is found below the respective critical temperatures of magnetic ordering. The magnetic moments are found solely on the rare earth atoms, while the moments of the remaining Pt and In atoms are absent or are too small to be detected while accompanied by the strong rare earth’s moments. The magnetocaloric (MCE) performance of RE5T2In4 (RE = Gd-Tm) is found quite good, especially while taking into account the compounds with RE = Ho and Er. Maximum magnetic entropy change (−ΔSMmax) reaches 11.8 (RE = Ho) or 11.4 J ⋅ kg−1 ⋅ K−1 (RE = Er) under magnetic flux density change of 0–9 T. Under the same conditions, the relative cooling power (RCP) and refrigerant capacity (RC) equal 607 and 495 J ⋅ kg−1 (RE = Ho) or 434 and 341 J ⋅ kg−1 (RE = Er).

Magnetic properties and cryogenic magnetocaloric effect in α-Gd2(MoO4)3 compound

Magnetic refrigeration technology has received extensive attention due to its application prospects in various fields. The research of magnetocaloric materials is the basis for the development of magnetic refrigeration technology. In this study, the α-Gd2(MoO4)3 was prepared by the high temperature solid state reaction. By X-ray diffraction characterization, α-Gd2(MoO4)3 crystallizes in monoclinic structure (space group C12/c1). Furthermore, its magnetism and magnetocaloric effect are investigated. The magnetic ordering temperature of α-Gd2(MoO4)3 is less than 1.8 K and there is a second-order phase transition. The maximum magnetic entropy changes are 20.8 and 32.7 J kg−1 K−1 under the field changes of 0–2 T and 0–5 T, respectively. Besides, the refrigeration capacity and relative cooling power are 142.0 and 190 J kg−1 under field change of 0–5 T. These properties indicate that α-Gd2(MoO4)3 is an excellent candidate for low temperature magnetic refrigeration.