Table-like Magnetocaloric Effect Research Articles

Broad table-like magnetocaloric effect in the full hydrogen liquefaction range in Gd3Ni6XY

Gd3Ni6SiAl, Gd3Ni6SiGa, and Gd3Ni6AlGa (Ce3Ni6Si2-type, Im-3m, N 229, cI44) present a broad table-like magnetocaloric effect in the full hydrogen liquefaction range (20-77K) with a real plateau wide enough to be competitive for refrigeration devices based on the Ericsson cycle. The characterization of the magnetocaloric variables (|ΔSMpk|= 6.60J/kgK, TEC(10)= 6.44J/kgK for Gd3Ni6SiGa, |ΔSMpk|= 6.05J/kgK, TEC(10)= 6.01J/kgK for Gd3Ni6SiAl, all at μ0ΔH=5T) state that they are among the best of table-like magnetocaloric materials in this temperature range. The physical origin of this smooth and wide table-like effect is the combination of a spin reorientation transition (which appears in Gd3Ni6XY when Si or Ga is introduced) with the paramagnetic to ferromagnetic transition, close to each other. The application of the Banerjee criterion and the evolution of the critical exponent with temperature n(T) confirm that both transitions are second order, which is extremely relevant for real applications. From the study of the magnetic properties it has been inferred that the introduction of Si induces a magnetic ground state with combined ferromagnetic and antiferromagnetic components which turns to fully ferromagnetic at very low field. The critical exponents (β, γ, δ, n) have been found for the paramagnetic to ferromagnetic transitions; the values of γ (from 1.22 to 1.36) suggest that the magnetic interactions are short-range, though the ensembles do not correspond to any particular universality class.

Broad table-like magnetocaloric effect in GdFeCo thin-films for room temperature Ericsson-cycle magnetic refrigeration

We demonstrate magnetocaloric entropy change and compensation temperatures in ferrimagnetic Gdx(Fe10Co90)100−x amorphous thin films with transition metal-rich and rare earth-rich configurations. Thin films are sputtered with same Gd/FeCo elemental ratio at different thicknesses and of various Gd/FeCo ratios at a constant thickness to understand the effect of these two parameters on an antiferromagnetically coupled magnetic sub-lattice system. Temperature- and field-dependent magnetic measurements [M(H,T)] and magnetocaloric studies are performed over a broad range of temperature (70–600 K) by applying a magnetic field of ±15 kOe on sputter deposited 90 nm thin films of Gdx(Fe10Co90)1−x(x = 30,40,50,55,70). The compensation temperature is found to increase with increasing Gd concentration for thin films of the same thickness. A high magnetocaloric entropy change around 0.97 J/kg K (ΔH = ± 15 kOe) is observed for thin films having the same Gd/FeCo elemental ratio. Furthermore, we observed a “table-like” magnetocaloric entropy change in GdFeCo thin film stacks with a high operational window (60 K) at a low applied field for an Ericsson magnetic regenerator around room temperature. The studies will provide important insight into magnetocaloric studies for Ericsson-cycle refrigeration in thin films having antiferromagnetically coupled sublattices.

Magnetic and magnetocaloric properties of Tb1.4Dy0.6In compound

This work summarizes the magnetic, thermal, magnetocaloric, and electrical transport properties of Tb1.4Dy0.6In and its critical behavior. First, we find that 60% Dy at the 2d (1/3, 2/3, 3/4) lattice sites of Tb2In (hexagonal Ni2In -type (space group- P63/mmc (No. 194))) leads to the formation of Tb1.4Dy0.6In, which undergoes a ferromagnetic transition at 155 K (T1) followed by an antiferromagnetic transition around 75 K (T2). Successive second-order magnetic transitions at T1 and T2 demonstrate a table-like hysteresis-free magnetocaloric effect around natural gas's liquefaction temperature (55–196 K). To understand the efficiency of Tb1.4Dy0.6In as a coolant, various cooling figures of merits such as isothermal entropy change, adiabatic temperature change, relative cooling power, the temperature averaged entropy change, and coefficient of refrigerant performance were determined. Along with the studies of magnetic properties, the critical exponent analysis endorses mean–field model that concord with the indirect long-range RKKY interaction between the rare-earth atoms in Tb1.4Dy0.6In. Furthermore, first-principle calculations indicate that the most hybridized dp states lie below the Fermi energy level and support the second-order magnetic nature of the transition. Overall, this study provides insights into the magnetocaloric properties of Dy-doped Tb2In and highlights its potential as an efficient coolant.

Table-like magnetocaloric effect due to field-induced inter-cluster interactions in Eu0.5Sr0.5MnO3–EuMnO3 composites

The table-like behavior of the magnetic entropy change is generally observed in rare-earth-based alloys (e.g. La(Fe,Si)13, Gd50Co45Fe5, Gd56Ni15Al27Zr2, GdCo x Al y etc). Here, we report similar table-like behavior in a bulk perovskite Eu0.5Sr0.5MnO3–EuMnO3 composite system with a working temperature span of ∼80 K for a field change of ∼70 kOe. AC susceptibility and time-dependent DC magnetization relaxation measurements confirm the presence of interacting ferromagnetic clusters with a Vogel–Fulcher freezing temperature of 42.7 K. The Langevin function fittings of the isothermal magnetization curves show a non-monotonous variation of cluster size with temperature. We propose a model for the high-field dependency of the ferromagnetic cluster coupling in the composite system. This widens the transition temperature region of long-range order formation and hence gives rise to the table-like magnetocaloric effect in Eu0.5Sr0.5MnO3–EuMnO3 composite systems.

Large table-like magnetocaloric effect in boron-doped Er5Si3B0.5 compound

In this work, Er5Si3B0.5 compound with the Mn5Si3-type hexagonal structure was synthesized, and the structure, magnetic properties, and the magnetocaloric effect were investigated theoretically and experimentally. The magnetic measurement results show a complex successive magnetic transition below TN. However, the magnetization of the Er5Si3B0.5 compound below TN is saturated under lower magnetic field relative to the Er5Si3 compound. Theoretical calculation indicates that this was attributed to the enhanced inter-orbital exchange interaction after doping B element. The complicated successive magnetic transitions contribute to the table-like magnetocaloric effect observed in the Er5Si3B0.5 compound with a wide temperature region. The maximum magnetic entropy change and the temperature averaged entropy change (30) are 10.1 and 9.02 J/kg K for the Er5Si3B0.5 compound under varying magnetic fields from 0 to 5 T, respectively. The temperature averaged entropy change (30) is reduced by just 11% compared to the maximum magnetic entropy change. While presenting an ideal magnetic refrigeration material with a large table-like magnetocaloric effect for hydrogen liquefaction, our work also demonstrates the feasibility of regulating magnetic behavior through enhanced orbital exchange interactions to develop magnetic refrigeration materials with outstanding performance.

Correlation between Magnetocaloric Properties and Magnetic Exchange Interaction in Gd54Fe36B10-xSix Amorphous Alloys.

Gd54Fe36B10-xSix (x = 0, 2, 5, 8, 10) amorphous ribbons were fabricated by melt-spinning technique. Based on the molecular field theory, the magnetic exchange interaction was analyzed by constructing the two-sublattice model and deriving the exchange constants JGdGd, JGdFe and JFeFe. It was revealed that appropriate substitution content of Si for B can improve the thermal stability, maximum magnetic entropy change and widened table-like magnetocaloric effect of the alloys, while excessive Si will lead to the split of the crystallization exothermal peak, inflection-like magnetic transition and deterioration of magnetocaloric properties. These phenomena are probably correlated to the stronger atomic interaction of Fe-Si than that of Fe-B, which induced the compositional fluctuation or localized heterogeneity and then caused the different way of electron transfer and nonlinear variation in magnetic exchange constants, magnetic transition behavior and magnetocaloric performance. This work analyzes the effect of exchange interaction on magnetocaloric properties of Gd-TM amorphous alloys in detail.

Achievement of reversible table-like magnetocaloric effect in MnCo1-Gd Ge alloys around room temperature

• The table-like magnetocaloric effect in MnCo 1- x Gd x Ge alloys are achieved. • Two successive magnetic transitions appear in the MnCo 1- x Gd x Ge ( x = 0.04, 0.06). • The refrigerant capacity reach 282 J/kg in MnCo 0.94 Gd 0.06 Ge with Δ H = 50 kOe. • The relative cooling power reach 335 J/kg in MnCo 0.94 Gd 0.06 Ge with Δ H = 50 kOe. • The maximum temperature span are 128 K in MnCo 0.94 Gd 0.06 Ge with Δ H = 50 kOe. The structural, magnetic and magnetocaloric properties in the Gd doped MnCo 1- x Gd x Ge alloys were investigated. With the increase of Gd content, the coexistence of Ni 2 In-type hexagonal structure and TiNiSi-type orthorhombic structure appear from the pure Ni 2 In-type hexagonal structure of MnCoGe. All samples undergo the second-order magnetic transition (SOMT). MnCo 1- x Gd x Ge ( x = 0.04, 0.06) have two successive magnetic transitions and a large reversible table-like MCE has been achieved around room temperature (RT). Moreover, the relative cooling power ( RCP ) and effective refrigeration temperature span (δ T FWHM ) with the magnetic field change of 50 kOe reach 335 J/kg and 128 K, respectively.

The Magnetocaloric Behaviors of Gd-based Microwire Arrays with Different Curie Temperatures

The desirable table-like magnetocaloric effect (MCE) was obtained by designing a new magnetic bed, which comprises three kinds of Gd-based microwire arrays with different Curie temperatures (TC). The TC interval among these wires is ~10 K. This new magnetic bed shows a smooth ferromagnetic to paramagnetic transition at ~100 K. In addition, a table-like magnetic entropy change (ΔSM) was obtained, ranging from ~92 K to ~107 K, with a maximum entropy change (−ΔSMmax) of 9.42 J/kgK for a field change (μ0ΔH) of 5 T. Notably, the calculated results of −ΔSM(T) corresponded to the experimental data for μ0ΔH = 5 T, suggesting that a microwire array-based magnetic bed with desirable magnetocaloric response can be designed. In addition, it was shown that a larger table-like temperature range and cooling efficiency can be achieved by increasing the interval of TC among microwire arrays. These important findings indicate that the newly designed magnetic bed is very promising for active magnetic cooling technology.

Tuning structure and magnetic properties of table-like magnetocaloric effect in Er6MnSb2 by zirconium substitution

In this study, zirconium (Zr) successfully substituted for erbium (Er) in Er6–xZrxMnSb2 (x = 0, 0.5, 1, 1.5) of the Fe2P type, with comprehensive characterizations on crystal structure, electronic structure and magnetic properties. According to synchrotron powder X-ray diffraction data analysis and density functional theory calculation, Zr does not randomly but preferentially occupy during the doping process and results in weaker magnetic exchange interactions and depressed ordering temperatures. The electronic structure data show that the doping of Zr can weaken interaction between Er and Mn atoms. Owing to multiple transitions, the Er6–xZrxMnSb2 (x = 0, 0.5, 1, 1.5) exhibit table-like magnetocaloric effect. Er6MnSb2 displays wide δTFWHM (full width at half maximum of the magnetic entropy change curve) of 116 K and high relative cooling power of 388.62 J/kg for 3 T. The maximum magnetic entropy change of Er6–xZrxMnSb2 is increased from 3.81 to 7.69 J/(kg·K) with the Zr content up from x = 0 to x = 1.5.

Tuning magnetic and table-like magnetocaloric effect of La0.6−xErxSr0.4MnO3(x = 0.0125, 0.05, 0.1) manganites

Polycrystalline samples of La0.6−xErxSr0.4MnO3 (x = 0.0125, 0.05, 0.1) have been prepared using the solid-state reaction method. X-ray powder diffraction confirmed a single-phase state and revealed a rhombohedral structure with the R¯3c space group in all samples. It is shown that the unit cell volume gradually decreases by replacing La with Er. The Curie temperature (Tc) decreases as the Er content rises. A downturn of the reciprocal value of the magnetic susceptibility versus temperature curve proves the presence of the Griffith phase above Tc. An occurrence of two overlapped transitions, from the ferromagnetic phase to the Griffith phase and from the latter one to the paramagnetic phase, in La0.6−xErxSr0.4MnO3 samples caused the significant expansion of the total transition temperature range as x increased. In turn, a widening of the transition temperature span gives rise to the spreading of the magnetic field induced entropy maximum over a broad temperature interval, resulting in a considerable enhancement of the relative cooling power.

Excellent magnetocaloric performance in the carbide compounds RE2Cr2C3 (RE = Er, Ho, and Dy) and their composites

The rare earth (RE) based alloys or compounds with excellent cryogenic magnetocaloric performance have received much research interest recently due to their potential applications of environmental friend magnetic refrigeration (MR) technology. Herein, three ternary RE-based carbide compounds RE2Cr2C3 (RE = Er, Ho, and Dy) were synthesized, an investigation of combined experimental and theoretical has been performed with regard to crystal structure, magnetic properties, magnetic phase transition as well as the magnetocaloric effect (MCE) and magnetocaloric performance. All the RE2Cr2C3 carbide compounds are crystallized in the orthorhombic type crystal structure (C12/m1 space group). The magnetic ground state was confirmed to be ferromagnetic (FM) for Er2Cr2C3, whereas antiferromagnetic (AFM) for Ho2Cr2C3 and Dy2Cr2C3 compounds by density functional theory calculation in addition to experimental observation. Large cryogenic MCE has been observed with the maximum isothermal magnetic entropy change (-ΔSMmax) of 15.20, 13.98 and 9.04 J/kgK for Er2Cr2C, Ho2Cr2C3 and Dy2Cr2C3 under the magnetic field change (ΔH) of 0–5 T, respectively. Additionally, low field table-like MCE has been achieved in the Er2Cr2C3/Ho2Cr2C3 composites, which is benefit for active applications. These results assess and highlight the potential applicative interest of RE2Cr2C3 carbide compounds in the field of cryogenic MR.

Composition-tunable magnetic properties of {Gd, Dy, Ho}6FeTe2, Ho6RuSb2 ternary compounds and Dy6FeSbBi, Dy6FeSbTe and Dy6FeBiTe quasiternary solid solutions

The magnetic ordering and magnetocaloric effect of polycrystalline Fe2P-type Gd6FeTe2, Dy6FeTe2, Ho6FeTe2 and Ho6RuSb2 ternary compounds and Dy6FeSbBi, Dy6FeSbTe and Dy6FeBiTe quasiternary solid solutions (space group P-62m, N 189, hP9) have been investigated using magnetic and heat capacity measurements. Gd6FeTe2 exhibits ferromagnetic ordering with Curie temperature (TC) of 212 K and magnetic entropy change of −4.9 J/kg⋅K in a field change of 50 kOe. Meanwhile, Dy6FeTe2, Ho6RuSb2, Dy6FeSbBi, Dy6FeSbTe and Dy6FeBiTe show high-temperature ferromagnetic ordering (TC) and low-temperature transformation of magnetic ordering (Tm), presenting a table-like magnetocaloric effect in a temperature range from TC to Tm and hard magnet properties at low temperatures. In field of 100 Oe, Ho6FeTe2 exhibits high-temperature antiferromagnetic ordering at TN = 26 K and low-temperature ferromagnetic transition at TC = 6 K with metamagnetic transformation in field lower than 10 kOe. It shows magnetocaloric effect with entropy change of −12.9 J/kg⋅K and −6.2 J/kg⋅K and magnetic enthalpy change of 580 J/kg and 62 J/kg at 22 K and 7 K, respectively, in a field change of 50 kOe.Tuning the magnetocaloric effect and the magnetic ordering via chemical composition is validated in the quasiternary Dy6FeSbBi, Dy6FeSbTe and Dy6FeBiTe solid solutions.

On the table-like magnetocaloric effect, microstructure and mechanical properties of LaxFe11.6 Si1.4 system

The structural, microstructural, magnetic and mechanical properties of LaxFe11.6Si1.4 (x = 1.3, 1.7) alloys prepared by arc melting have been studied. The Rietveld refinement of the X-ray diffraction (XRD) patterns shows that increasing La content leads to increase in secondary phases and decrease in 1:13 phase from 88% to 71%. Thermomagnetic measurements show that there is not much change in the Curie transition, however the thermal hysteresis increases with the increase in La content. Table like magnetocaloric effect was observed from 180 K to 200 K in both the alloys. A magnetic entropy change of 19.73 J/kg-K and 15.24 J/kg-K were observed at a low field change of 1 T in La1.3Fe11.6Si1.4 and La1.7Fe11.6Si1.4 alloy respectively. The magnetic entropy change further increases to 23.48 J/kg-K at 183 K and 19.51 J/kg-K at 180 K under an applied filed change of 7 T and the effective magnetic refrigeration capacity was found to be 672 J/kg and 581 J/kg in La1.3Fe11.6Si1.4 and La1.7Fe11.6Si1.4 alloys respectively at a field change of 7 T. The adiabatic temperature was found to be 1.16 K and 2.45 K under a field change of 1 T and increases to 6.05 K and 8.13 K at an applied field change of 7 T in La1.3Fe11.6Si1.4 and La1.7Fe11.6Si1.4 alloy respectively. Increase in La content leads to increase in the mechanical strength suggesting better machinability, thus making them suitable for viable magnetic refrigeration applications.

Tablelike magnetocaloric effect and enhanced refrigerant capacity in EuO1−δ thin films

The effect of electron doping of $\mathrm{Eu}{\mathrm{O}}_{1\text{\ensuremath{-}}\ensuremath{\delta}}$ thin films through oxygen vacancies ($\ensuremath{\delta}=0$, 0.025, and 0.09) upon the magnetocaloric response is presented. The films each showed a paramagnetic to ferromagnetic transition around 65 K, with an additional magnetic ordering transition at higher temperatures in the oxygen deficient samples. All transitions are observed to be of second order. A maximum magnetic entropy change of 6.4 J/kg K over a field change of 2 T with a refrigerant capacity of 223 J/kg was found in the sample with $\ensuremath{\delta}=0$, and in all cases the refrigerant capacities of the thin films under study were found to exceed that reported for bulk EuO. Adjusting the oxygen content was shown to produce tablelike magnetocaloric effects, desirable for ideal Ericsson-cycle magnetic refrigeration. These films are thus excellent candidates for small-scale magnetic cooling technology in the liquid nitrogen temperature range.

Sm26Co11Ga6-type R26{Co, Ni}6.5-9.4Ga10.5-7.6 compounds (R = Gd–Er): Crystal structure, magnetic ordering and heat capacity

The crystal structure of novel Sm26Co11Ga6-type {Gd - Er}26Ni6.5-8Ga10.5-9 compounds (space group P4/mbm, N 127, tP86) has been established using powder X-ray diffraction. The magnetic ordering and magnetocaloric effect of polycrystalline Er26Co9Ga8, Tb26Ni8Ga9 and Tb26Co9.4Ga7.6 have been investigated using magnetic and heat capacity measurements. Er26Co9Ga8 and Tb26Ni8Ga9 show mixed ferro-antiferromagnetic ordering and remarkable permanent magnet properties at low temperatures. Er26Co9Ga8 exhibits a large magnetocaloric effect with magnetic entropy change of −11.8 ​J/kg⋅K at 12 ​K and adiabatic temperature of 9.6 ​K for a field change of 50 ​kOe. The ‘Gd26Ni8Ga9’ alloy is composed of 88 ​wt% of Gd26Ni8Ga9 and 12 ​wt% of GdNi which are both soft ferromagnetic. Due to their close Curie temperatures, the composite of Gd26Ni8Ga9 and GdNi displays a table-like magnetocaloric effect with a wide temperature range from 68 ​K to 103 ​K.

Table-like magnetocaloric effect around room temperature of antiperovskite composite materials based on Mn3Sn1-xGaxC

The Mn3Sn1-xGaxC materials based on Mn3SnC with Sn partially replaced by Ga were prepared and their phase transitions were studied. With increasing Ga content, the Curie temperatures (Tc) of Mn3Sn1-xGaxC gradually decrease, but the large phase transition entropy (ΔS) is retained. Antiperovskite composite magnetic refrigerant was designed and synthesized by mixing the Mn3Sn1-xGaxC materials with different phase transition temperatures. The composite presents a nearly table-like magnetic entropy change (-ΔSM)-T curve near room temperature. Compared with Mn3SnC, the full width at half maximum (ΔTFWHM) of (-ΔSM)-T curves of the composite increased from 5 K to 44 K, and the refrigerant capacity (RCP) increased from 27.1 J/kg to 58.67 J/kg at 5 Tesla (T). This composite material is beneficial to magnetic Ericsson cycle, providing a new method for developing practical magnetic refrigerants in antiperovskite compounds.

Observation of table-like magnetocaloric effect and large refrigerant capacity in Nd6Fe13Pd1–xCux compounds

The table-like magnetocaloric effect is significant for the magnetic refrigeration applications above 20 K based on the Ericsson cycle. Herein, we prepared a series of Nd6Fe13Pd1–xCux (x = 0.05, 0.1, 0.15) compounds by the arc-melting method. These compounds show the single crystalline phase in the tetragonal Nd6Fe13Si-type structure with the space group I4/mcm. A magnetic phase transition from ferromagnetism to antiferromagnetism and a metamagnetic transition from the antiferromagnetic state to the ferromagnetic state are observed in each of the compounds. The compounds exhibit table-like magnetocaloric effects with large refrigerant capacities. A constant ΔSM in a temperature span of 40 K in the Nd6Fe13Pd0.85Cu0.15 compound are observed. For a field change of 0–5 T, the peak values of –ΔSM for the Nd6Fe13Pd0.95Cu0.05, Nd6Fe13Pd0.90Cu0.10, and Nd6Fe13Pd0.85Cu0.15 compounds are estimated to be 4.8, 4.6 and 4.4 J/(kg·K) with corresponding refrigerant capacity values of 323, 331 and 316 J/kg, respectively. The obtained table-like magnetocaloric effects with large refrigerant capacities as well as fairly small thermal and magnetic hysteresis deem these series of compounds good candidates for single-phase magnetic refrigeration based on the Ericsson cycle.

Enhanced refrigeration capacity in Ho1-xDyxB2 compounds around liquid hydrogen temperature

In this study, the crystal structure, magnetic properties, and magnetocaloric effect of Ho1-xDyxB2 compounds were investigated. It was found that nearly single-phase (Ho,Dy)B2 compounds with the AlB2-type structure directly form in the as-arc melted alloys and have two successive magnetic transitions. With the increase of Dy concentration x from 0 to 0.8, the spin reorientation transition temperature remains at about 13 K, while the Curie temperature significantly increases from 16 to 43 K. As a result, the full-width at half-maximum of the magnetic entropy change versus temperature curve increases from 19.9 to 48.2 K. Also, these Ho1-xDyxB2 compounds exhibit a large refrigeration capacity of 523–635 J kg−1 under a magnetic field change of 5 T, although the maximum magnetic entropy change decreases from 34.3 to 17.2 J kg−1 K−1. In addition, Dy-containing compounds exhibit a table-like magnetocaloric effect compared with the HoB2 compound. Our results indicate that Ho1-xDyxB2 compounds are a promising candidate for cryogenic magnetic refrigeration around liquid hydrogen temperature.

Table-like magnetocaloric effect and large refrigerant capacity in Nd6Fe13Pd1-xAgx compounds

Table-like magnetocaloric effect is significant for using the Ericsson cycle in the applications of magnetic refrigeration above 20 K. A series of Nd6Fe13Pd1-xAgx (x = 0.1, 0.2, 0.3, 0.4) compounds were prepared by the arc-melting method, showing a single crystalline phase in the tetragonal Nd6Fe13Si-type structure with the space group I4/mcm. All of the compounds undergo a first-order magnetic transition from the ferromagnetism to antiferromagnetism with the temperature increases, as well as a metamagnetic transition from antiferromagnetic state to ferromagnetic state induced by an applied field. The table-like magnetocaloric effects with large refrigerant capacities in these compounds have been observed, which is very rare in a single phase. A constant ΔSM in a temperature span of 60 K in the Nd6Fe13Pd0.6Ag0.4 compound can be observed. For a field change of 0–5 T, the peak values of |ΔSM| for the Nd6Fe13Pd0.9Ag0.1, Nd6Fe13Pd0.8Ag0.2, Nd6Fe13Pd0.7Ag0.3 and Nd6Fe13Pd0.6Ag0.4 compounds are estimated to be 4.9 J kg−1 K−1, 4.5 J kg−1 K−1, 3.5 J kg−1 K−1 and 3.4 J kg−1 K−1 with the corresponding refrigerant capacity values of 327 J kg−1, 315 J kg−1, 306 J kg−1 and 289 J kg−1, respectively. The table-like magnetocaloric effect and large working temperature spans make the series of compounds a good candidate for single-phase magnetic refrigeration material at low temperature based on the Ericsson cycle.

The Wide Operating Temperature Range in the Magnetocaloric Composite Formed by RMn2Si2 (R=Tm, Tb, and Dy) and HoCoSi Compounds

RMn2Si2 (R = Tm, Dy, and Tb) and HoCoSi alloys, presenting multiple magnetic phase transitions (except for TmMn2Si2 and HoCoSi) and large magnetocaloric effect (MCE), were physically mixed to produce a composite magnetic refrigerant. The used concentration of each alloy was 0.1(TmMn2Si2) + 0.35(DyMn2Si2) + 0.4(TbMn2Si2) + 0.15(HoCoSi). X-ray diffraction and magnetization measurements were used to investigate the crystallographic and magnetic properties of the samples. The results indicate the maximum values of magnetic entropy change ( $$ -{\Delta S}_M^{max} $$ ) of ~ 4.6 J/kg K under magnetic field change (ΔH) of 50 kOe. A large table-like MCE was observed for the composite sample. The full width at half maximum of ΔSM peak (δTFWHM) values reaches ~ 60.4 K (ΔH = 20 kOe) and ~ 67.2 K (ΔH = 50 kOe), which correspond to a respective ΔSM peak broadening of 230% and 180% for the composite sample compared with each compound studied individually. Such property is important for a material to operate in an ideal Ericsson cycle.