Magnetic Refrigeration Applications Research Articles

Magnetic energy product and hysteresis behavior of antiperovskite Mn3AlN: Monte Carlo Simulation

In this study, we investigated the magnetic properties, magnetocaloric effect, magnetic energy product, and hysteresis behavior of Mn3AlN antiperovskite using Monte Carlo (MC) simulation techniques. We examined the effect of magnetic field on magnetic behavior. As the magnetic field values h increase, the amplitudes of both the specific heat peaks and the susceptibility also increase. For various external magnetic fields and temperatures, we obtained the adiabatic temperature change and the magnetic entropy change. The compound displayed a direct magnetocaloric effect. Furthermore, the relative cooling power (RCP) values for a magnetic field strength of 60 kOe are 117.54 J/kg. The hysteresis loops were used to calculate the energy product BH. These findings suggest that our material is an excellent fit for magnetic refrigeration and information storage applications.

{Gd22Ni22}: A double-shell nanocluster exhibits large magnetocaloric effect

Atomically well-defined metal nanoscale clusters have attracted significant interest owing to their fascinating structures and wide potential applications. The Gd (III) containing clusters, in particular, attract great research attention due to their potential magnetic refrigeration applications. Here, we report the synthesis of a gigantic double-shell 3d-Gd cluster, {Gd22Ni22}, which is composed of [Gd5Ni2(μ2-OH)4(μ2-OH)6]9+ and [Gd6Ni9(μ2-OH)20(μ3-OH)10]6+ structural units. Magnetic characterization reveals that the {Gd22Ni22} cluster exhibits a large magnetocaloric effect (MCE), with an isothermal magnetic entropy change of 46.0 J kg−1 K−1 at 2.0 K for ΔH = 7 T, which is one of the largest among all the high-nuclearity Ni–Gd clusters. The large magnetic entropy change of {Gd22Ni22} cluster is closely related to its weak magnetic interaction.

The varying nature of the martensitic phase transition and associated entropy changes in a Co and Cr doped pseudo-ternary Heusler alloy system

We have investigated the magnetostructural phase transitions and the associated entropy changes in a system of three Heusler alloys, namely: Ni2Mn0.55Cr0.45Ga, Ni2Mn0.55Co0.10Cr0.35Ga, and Ni2.15Mn0.75Cr0.1Ga. All three alloys exhibited first-order martensitic phase transition. An inter-martensitic phase transition raised the magnetic and structural phase transition temperatures, and partially decoupled the said transitions. Furthermore, field magnetization measurements demonstrated that a significant reduction in magnetic hysteresis is achieved in the Ni2Mn0.55Co0.10Cr0.35Ga compound, resulting in improved effective refrigerant capacity values. The largest magnetic entropy change of −23.5 J/kg K and refrigeration capacity of 97.7 J/kg were observed in Ni2.15Mn0.75Cr0.1Ga. This observation of mitigated deficiencies in materials experiencing a first-order phase transition is relevant towards their application in magnetic refrigeration.

A comparative study of magnetic behaviours in bulk and ribbon samples of PrMn2Ge2 compound

The magnetic properties of PrMn2Ge2 samples in both the as-cast bulk and melt-spun ribbon forms have been investigated in detail by a comprehensive set of x-ray and neutron powder diffraction, magnetic and heat capacity measurements and corresponding sets of data analyses. Thermal expansion measurements indicate the presence of magnetoelastic coupling effects around all transition temperatures in the bulk sample. The bulk modulus K0 = 42.0 GPa and its first derivative K0’ = 18.7 have been derived from the pressure-volume data. The Curie temperature from the intralayer antiferromagnetism (AFl) of PrMn2Ge2 to a canted spin structure (Fmc) is TCinter = 332 K for the bulk sample, decreasing to TCinter = 320 K for the ribbon sample. The critical components γ, β and δ of this second order magnetic transition as determined from Kouvel-Fisher analyses, indicate long range magnetic interactions around TCinter. Based on these critical exponents the magnetization, field and temperature data around TCinter collapse onto two curves obeying the single scaling equation M(H,ε)=εβf±(Hεβ+γ). The Debye temperatures and the density of states at the Fermi level are θD=306K and N(EF)=3.47state/eVatom for the bulk sample and θD=320K and (EF)=2.18state/eVatom for the ribbon sample with the nuclear specific heat coefficient for bulk PrMn2Ge2 derived from the splitting of the nuclear hyperfine levels as CN = 517 mJ mol−1 K−1. With a field change of ΔB = 5 T, the maximum values of the magnetic entropy changes -ΔSmax in the region around TCinter are -ΔSmax = 3.00 J/kg K and 2.35 J/kg K for the bulk and ribbon samples respectively, while the relative cooling power (RCP) for the ribbon-spun sample, RCP = 135.9 J/kg, is significantly higher than the value of RCP = 116.6 J/kg for the bulk sample. These findings indicate that PrMn2Ge2 could be a promising candidate for magnetic refrigeration applications in the room temperature region.

The large magnetocaloric effect in GdErHoCoM (M = Cr and Mn) high-entropy alloy ingots with orthorhombic structures

High-entropy alloys (HEAs) with significant magnetocaloric effects (MCEs) have attracted widespread attention due to their potential magnetic refrigeration applications over a much more comprehensive temperature range with large refrigerant capacity (RC). However, most of them are metallic glasses (MGs) with problems of limited size, resulting in the difficulty of further applications. Therefore, research on HEAs with crystalline structures and giant MCE is urgently needed. In this paper, GdErHoCoM (M = Cr and Mn) rare-earth HEA ingots with orthorhombic structures are developed, and their magnetic behavior and MCE are studied in detail. Phase investigations find that the main phase of GdErHoCoM ingots is probably (GdErHo)Co with an orthorhombic Ho3Co-type structure of a space group of Pnma. The secondary phases in GdErHoCoCr and GdErHoCoMn are body-center-cubic Cr and Mn-rich HoCo2-type phases, respectively. Magnetic investigations reveal that both ingots undergo a first-order magnetic phase transition below their respective Neel temperatures. Above their respective Neel temperatures, a second-order transition is observed. The Neel temperatures are 40 and 56 K for GdErHoCoCr and GdErHoCoMn, respectively. Additionally, the GdErHoCoCr and GdErHoCoMn ingots exhibit maximum magnetic entropy changes and RC values of 12.29 J/kg/K and 746 J/kg and 10.13 J/kg/K and 606 J/kg, respectively, under a magnetic field of 5 T. The ingots GdErHoCoM (M = Cr and Mn) show excellent MEC properties and can be manufactured easily, making them promising for magnetic refrigerant applications.

Magnetic and magnetocaloric effect of Ba[formula omitted]FeReO[formula omitted] double perovskite: Ab-initio and Monte Carlo studies

In this paper, the double perovskite Ba2FeReO6 was studied using ab initio calculations and Monte Carlo simulation within the Ising model framework. The band structure and density of states of the compound were investigated. Moreover, energy calculations were employed to determine the magnetic anisotropy and exchange interactions for conducting a Monte Carlo study. The calculated curie temperature Tc of the compound is found 296 K, which agrees with the experimental value (Tc = 303 K). We have studied also the magnetic and magnetocaloric properties, the maximum entropy change (ΔSmax) and the relative cooling power (RCP) at a magnetic field of h=60 kOe are 4.28 J/kg K and 255 J/kg, respectively. Furthermore, the energy product was calculated using hysteresis loops. These findings suggest that Ba2FeReO6 is a competitive candidate material for magnetic refrigeration applications.

A Short Review on the Evolution of Magnetocaloric La(Fe,Si)13 and Its Fabrication through Melt Spinning.

Energy-efficient refrigeration technology needs to advance ineluctably due to rising energy consumption and diminishing fossil fuel and primitive hydrocarbon reserves. Further, the existing gas compression method releases huge amount of chlorofluorocarbons (CFCs) that deplete the ozone layer. This is a global concern, which demands an immediate remedial technology. As a potential solution to the problem of sustainability and a means of meeting the ever-increasing demand for energy, environmentally friendly and socially responsible renewable energy sources could serve as an ideal replacement for traditional refrigeration technology. Solid-state refrigeration using magnetocaloric materials is one prominent technique that can be adopted for clean and economical refrigeration or cooling requirements. In this review, we briefly introduce the present understanding on magnetocaloric LaFe13-xSix alloys with a specific emphasis on their application in magnetic refrigeration. This paper deals with the advantages and disadvantages of different synthesis methods for producing LaFe13-xSix and enhancing its magnetocaloric effects. Annealing time, yield, composition, and relative cooling power are examined as prospective industrial implementation factors for the La(Fe,Si)13 synthesis process. The initial sections have been devoted to an overview of the magnetocaloric effect and its different types and history. Further, the article reviews the evolution of a new preparation method called melt spinning, other synthesizing methods, and some developments around the world for the prototypes of La(Fe,Si)-based magnetic refrigeration methods. According to the findings in the scholarly literature, the synthesis process of melt spinning has the potential to be commercialized because of its capacity to create huge quantities of La(Fe,Si)13 with a high purity in a very short amount of time.

First principal calculation of the physical proprieties of the ternary intermetallic compound Gd2Cu2Cd for magnetic refrigeration applications

The manuscript explores the electromagnetic and magnetocaloric characteristics of the intermetallic compound Gd 2 Cu 2 C d . One of the key findings is that Gd2Cu2Cd possesses a magnetic moment of approximately 7.13 μB. The simulated magnetic properties illustrate a second-order phase transition from ferromagnetic (FM) to paramagnetic (PM) occurring at approximately 130 K. This material exhibits a substantial magnetocaloric effect (MCE) across various external magnetic field strengths. To be more specific, this transition occurs at an external magnetic field of 4.0 T, in particular, at an external magnetic field of 4.0 T, the extreme magnetic entropy change ( Δ S mag ) is measured at 3.58 J/kg.K, and the relative cooling power (RCP) reaches 28 J/kg. Notably, with an increase in the external magnetic field, the maximum value of ( ΔS mag ) increases significantly, and the Curie temperature ( T C ) shifts toward lower temperatures. These results suggest that Gd 2 Cu 2 Cd has significant potential for applications in magnetic refrigeration that leverage the magnetocaloric effect.

Magnetocaloric effect modeling of dysprosium-transition metal based intermetallic alloys for magnetic refrigeration application using hybrid genetic algorithm based support vector regression intelligent method.

Intermetallic alloy containing rare earth dysprosium ions with the associated unfilled 4f shell electrons and sub-lattice of 3d-transition metal, results into fascinating magnetic properties which are useful for green refrigeration technological application. Magnetocaloric effect remains the fundamental principle upon which magnetic refrigeration technology is based while this cooling technology has advantages of cost effectiveness, high efficiency and environmental friendliness as compared with the existing conventional gas compression systems. Maximum magnetic entropy change (which controls the hugeness of magnetocaloric effect) of intermetallic alloy Dy-T-X (where T = transition metal and X = any other metal or nonmetal) is modeled in this work using hybrid genetic algorithm based support vector regression (GSVR) computational intelligent method with applied magnetic field, ionic concentration and ionic radii descriptors. The developed GSVR-G model with kernel Gaussian function outperforms GSVR-P model with polynomial function with improvement of 85.23%, 78.82% and 78.67% on the basis of the computed correlation coefficient (CC), mean absolute error (MAE) and root mean square error (RMSE) on testing sample, respectively. The developed model further investigates the influence of applied external magnetic field on magnetocaloric effect of DyCuAl intermetallic alloy. The developed models in this work circumvent experimental challenges of magnetocaloric effect determination while the recorded precision of the developed model further opens doors for possible exploration of these intermetallic compounds for addressing environmental challenges associated with the present system of cooling.

Development and Validation of a 3-D Analytical Fluidic Model in Cartesian Coordinates for a Magnetic Refrigeration Application

This paper focuses on the development and validation of a three-dimensional (3-D) analytical model based on the formal resolution of the incompressible Navier-Stokes equations in Cartesian coordinates. This analytical fluidic model calculates the evolution of the fluid flow velocity for various pressure gradient shapes (i.e., square, trapezoidal, ramp, triangle, sinusoidal signals, etc.), with or without mean value, using Fourier series. The model can consider square and rectangular channels of any dimensions in terms of height, width, and depth. It allows for the study of different types of fluid flow and geometries. The introduction highlights the significance of analytical modeling, particularly in the context of Magnetic Refrigeration (MR) technologies. The model assumptions and governing equations are presented. The results obtained from the analytical model are validated and show good convergence with those obtained using the COMSOL Multiphysics® software. The comparison demonstrates a high level of agreement between the two models. The analytical model performs well in terms of computation time and accuracy. It will be coupled with an analytical thermic model and used to optimize Active Magnetic Regenerative Refrigeration (AMRR) cycles. The ultimate objective is to determine an optimal pressure gradient evolution in order to maximize heat exchange in a regenerator channel.

Magnetic properties and large cryogenic magnetocaloric effects in the RE2SiO5 (RE = Gd, Dy, Ho, and Er) silicates

We herein investigated four rare earth (RE)-based oxides, the RE2SiO5 (RE = Gd, Dy, Ho, and Er) silicates, regarding their structural and cryogenic magnetic properties. All the RE2SiO5 silicates are found to crystallized in a monoclinic structure. X-ray photoemission spectroscopy spectra illustrate that RE, Si and O elements in RE2SiO5 silicates are present as RE3+, Si4+, and O2−, respectively. The Dy2SiO5 reveals a first-order magnetic transition around 4.5 K. The magnetic phase transition temperatures are probably below 2 K for the RE2SiO5 (RE = Gd, Ho, and Er) silicates. Large cryogenic magnetocaloric effects (MCE) and good magnetocaloric performances were observed in the RE2SiO5 silicates. The MCE parameters in terms of the maximum magnetic entropy changes, the temperature-averaged entropy change (5 K-lift) and refrigerant capacity under a magnetic field change of 0–5 T are determined to be 35.5, 30.4 J/kgK, and 215.7 J/kg for Gd2SiO5, to be 13.3, 12.9 J/kgK, and 190.5 J/kg for Dy2SiO5, to be 15.3, 15.1 J/kgK, and 274.1 J/kg for Ho2SiO5 and to be 17.9, 16.5 J/kgK, and 181.14 J/kg for Er2SiO5, respectively. These derived values of MCE parameters of the RE2SiO5 silicates, especially for Gd2SiO5, are at similarly high level with or better than those of the updated candidate materials, making them also of potential for practical magnetic refrigeration applications.

Tunable Curie temperature and large magnetocaloric effect in off-stoichiometric LaxMMxFe10.2Co1.0Si1.8 alloys

NaZn13-type La(Fe, Si)13-based alloys have been considered as one of the most promising candidates for magnetic refrigeration application near room temperature. In this paper, we present the structural and magnetic properties of off-stoichiometric alloys with composition of LaxMMxFe10.2Co1.0Si1.8 (x = 0.50, 0.55, 0.60, 0.65 and 0.70), in which MM stands for La-Ce-Pr-Nd mischmetal. Rietveld refinement of the XRD patterns indicated that adding excessive rare earth suppressed the precipitation of α-Fe phase, but resulted in the increase of secondary rich-rare-earth phases. The Curie temperature changed slightly with x around room temperature. For a field change of 3 T, the off-stoichiometric alloys exhibit maximum isothermal entropy change in a range of 5.1 ∼ 6.5 J/kgK, which is higher than that of the stoichiometric alloy. The corresponding values of relative cooling power are found to be 221 ∼ 253 J/kg. The present study provides some scientific guidance for developing magnetic refrigerants near room temperature.

Large magnetocaloric effect in gadolinium-rich silicate NaGd9(SiO4)6O2

Magnetic cooling has aroused great interest in cryogenic research due to its high energy efficiency. Due to the large magnetic moment and completely quenched orbital momentum, Gd-based oxides have been promising candidates for cryogenic magnetic refrigerant. In this article, the magnetic properties and magnetocaloric effect of NaGd9(SiO4)6O2 (NGSO) single crystal are investigated. The maximum magnetic entropy change of 60 J·kg−1K−1 is observed with the magnetic field changing from 0–7 T at 2.6 K. The large magnetic entropy change can be attributed to high metal/ligand ratio and weak exchange interaction. Particularly, due to the large density of NGSO, the volumetric entropy change is identified to be 382.8 mJ·cm−3K−1, which surpasses most reported magnetic refrigerants in volume units. Besides, the excellent refrigerant capacity and adiabatic temperature change have been determined to be as high as 370.4 J·kg−1 and 7.4 K under the applied field change of 0–7 T and 0–2 T, respectively. These performances suggest that NGSO is a promising candidate for low-temperature magnetic refrigeration applications.

Magnetocaloric Effect In Full-Heusler Rh2SmIn Compound Based on Rare Earths Using DFT and Monte Carlo Studies

Abstract Magnetocaloric refrigeration is an integral part of technology and is under constant investigation. In this regard, the characterization of the magnetocaloric materials used is of major concern. In this study, we used different approaches to better understand the mechanisms underlying the magnetic and magnetocaloric properties of Rh 2 S mIn Full-Heusler. A physical model is suggested to explain the magnetic interaction within this material. Utilizing the density functional theory, exchange couplings and magnetic phase stability in Rh 2 SmIn have been attempted as well in order to understand and clarify the various magnetic interactions in this compound. The magnetic and magnetocaloric properties were examined with Monte Carlo simulation (MCS) based on the Ising model. The transition temperature, magnetic entropy change, and relative cooling power (RCP) were computed and found to be in good agreement with experimental evidence. According to the results, Rh 2 S mIn is a good candidate to be used in magnetic refrigeration applications at high temperature.

Investigation of magnetocaloric effect in Holmium substituted Dysprosium iron garnet for magnetic refrigeration applications

The Dy1-xHox3Fe5O12(Ho-DyIG) with x=0.0 to 1.0 garnet samples are prepared by solid-state reaction route by sintering them at 1200 °C for 24 hours followed by calcination. The samples have simple cubic structure with Ia3¯d space group. The lattice constant is obtained from the Rietveld refinement technique and is found to be decreased from 12.4181Å to 12.3858Å with Ho doping. All the samples exhibit ferrimagnetic behavior below their transition temperature of 555K(x=0.0) to 545Kx=1.0. This drop in transition temperature is attributed to the dilution of Fea-O-Fed networks. All the samples show magnetic compensation because of the strong anisotropy induced at lower temperatures. In addition, we have also observed spin reorientation in all the samples of Ho-DyIG series. We have performed magnetocaloric measurements for x=0.4 and 0.8 samples and observed that the magnetic entropy is improved from 3.92 to 4.30J/kgK when measured at a maximum applied field of 5T around their respective Belov tranistion temperature i.e. TB. We have seen both normal and inverse magnetocaloric effects in these samples. To test the extent of magnetic refrigeration capacity, we have calculated the Relative Cooling Power, which comes out to be 364.6J/kg for x=0.4 and 313.0J/kg for x=0.8 samples at 5T magnetic field. The Arrott plots are also investigated and they have positive slope suggesting the presence of second-order phase transition in our samples.

Ab-initio and Monte Carlo studies of magnetic and magnetocaloric properties of antiperovskite Mn[formula omitted]AlN

In this study, we systematically investigate the electronic, magnetic, and magnetocaloric properties of Mn3AlN antiperovskite. This system is examined through first-principles computations using density functional theory (DFT) and Monte Carlo (MC) simulations. Based on the density of state and band structure, it is found that Mn3AlN behaves as a ferromagnetic metallic material. Additionally, we calculate the magnetic anisotropy and exchange interactions, which are parameters of the Hamiltonian, and incorporate them into the MC simulation. Concerning the magnetic properties, the critical temperature of the antiperovskite (Tc= 811 K) is almost similar to the experimental value (Tc= 818 K). Furthermore, we also investigate the magnetocaloric properties and find that the relative cooling power (RCP) values and maximum entropy change for a magnetic field strength of 5 T are 93.96 J/kg and 12.55 J/kg K, respectively. These results suggest that Mn3AlN is a promising candidate for magnetic refrigeration applications.

Large Magnetocaloric Effect of PrNi Compound at Liquid-Hydrogen Temperatures

In the work, polycrystalline PrNi compound was synthesized by the arc-melting method. The crystal structure is determined as CrB type orthorhombic structure (Space group Pnma). The Curie temperature (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> ) is determined to be 21.0 K according to the maximum absolute value of first derivative of magnetization. The slope of the Arrott plots is positive around phase transition temperature, indicating of the second-order phase transition characteristic. The magnetic entropy change (-ΔS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</sub> ) was calculated from the isothermal magnetization data based on the Maxwell’s relationship. The maximum value of -ΔS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</sub> is calculated to be 7.3 and 13.0 J/kg K for the magnetic field changes of 0-2 T and 0-5 T, respectively. The large magnetocaloric effect (MCE) around 21.0 K with second-order phase transition feature indicates that PrNi is a great potential in the application of magnetic refrigeration for hydrogen liquefaction.

Excellent magnetocaloric effect at cryogenic temperature in amorphous (Fe35RE65) (RE = Er, Dy and Gd) alloys

Heavy Rare Earth (HRE) elements have been selected for exploring the structural, magnetic and magnetocaloric performance of amorphous alloys (Fe35RE65) (RE = Er,Dy and Gd). These alloys undergo a second-order transition from ferromagnetic (FM) to paramagnetic (PM) state in the temperature range of liquid hydrogen (Tc < 70 k) for both Fe35Er65 and Fe35Dy65, and at room temperature (Tc = 273 k) for Fe35Gd65. Furthermore, For an applied magnetic field (H = 50 kOe), the entropy change (–ΔSM)max values are 9, 10.5 and 11.4 J/kg.K for Fe35Er65, Fe35Dy65 and Fe35Gd65, respectively. The observed relative cooling power (RCP) values of these amorphous alloys are 296, 302 and 312 J.kg−1 for Fe35Er65, Fe35Dy65 and Fe35Gd65 respectively. These findings make (HRE) – amorphous alloys promising materials for magnetic refrigeration applications with excellent magnetocaloric effects.

The symmetry aspect of magnetocaloric effect in LaxBi0.3-xCa0.7MnO3 manganites

Manganites exhibit many novel properties, such as giant magnetoresistance and a large magnetocaloric effect (MCE). In this work, we report the magnetic properties and magnetocaloric effects of polycrystalline Bi0.3-xLaxCa0.7MnO3 (x = 0, 0.1, 0.2) ceramics from perspective of symmetry, where Raman active modes and corresponding phonons are used as probes to detect charge disorder and local structure distortion. Further, the large MCE is elucidated by the La doping induced Jahn-Teller distortion and valence perturbations. The orthorhombic and rhombohedral structural transition in doping manganites has shown a link between the complex magnetic phase transition and magnetic entropy. We attribute these intriguing behaviors to the temperature-dependent competition between the orbital order and charge order. Our results provide an approach to improve the MCE of manganite systems for future magnetic refrigeration applications.

Rare‐Earth‐Free Mn30Fe20−xCuxAl50 Magnetocaloric Materials with Stable Cubic CsCl‐Type Structure for Room‐Temperature Refrigeration

AbstractMagnetic refrigeration technology based on the magnetocaloric effect (MCE) of magnetic substances has been considered a prominent, energy‐efficient, and environmentally benign cooling method. Exploring suitable magnetic substances is a prerequisite for practical applications. A family of rare‐earth‐free magnetocaloric materials called Mn30Fe20−xCuxAl50 alloys is identified room‐temperature refrigeration, which are derived from the well‐known MnAl‐based permanent magnets. As expected from experimental and theoretical investigations, all of the Mn30Fe20−xCuxAl50 alloys are crystallized in a stable cubic CsCl‐type crystal structure, revealing a single second‐order type magnetic phase transition (MPT) with tunable MPT temperature. They also exhibit a large reversible MCE and good magnetocaloric performances in a wide temperature range. Crucially, these Mn30Fe20−xCuxAl50 alloys represent a rare case of magnetic materials belonging to a large family that can be fabricated from low‐price, earth‐abundant, and non‐toxic elements. They could provide new choices for practical room‐temperature magnetic refrigeration applications.