FM Phase Research Articles

Exploring the electronic, magnetic and thermoelectric properties of TbPtBi half-Heusler: DFT study

Abstract In this investigation, we employed density functional theory to scrutinize the structural, electronic, magnetic, thermoelectric, and phonon properties of the topological half-Heusler (HH) TbPtBi compound. The stable phonon dispersion spectrum affirms the dynamical stability of the compound. The inclusion of spin-orbit coupling (SOC) significantly influenced the compound’s electronic and thermoelectric properties. The density of state (DOS) confirmed the impact of SOC on the topologically non-trivial metallic behavior of TbPtBi under the equilibrium lattice constant. The SOC altered the DOS at the Fermi level, leading to band splitting and a notable 70% reduction in state density. The Tb-4f electrons in the compound induce total magnetization in AFM (−5.93 µB/cell) and FM (5.94 µB/cell) phases, while SOC eliminates this magnetization. The thermoelectric performance of TbPtBi under compressive and tensile strain has been systematically studied. The result indicate that compressive strain causes a notable increment in Seebeck coefficient and Power factor (20.4 × 1011 W K−2 m−1) of this compound at room temperature. High thermoelectric performance under compressive strain in the HH compound TbPtBi might open new avenues for investigating other topological thermoelectric materials.

Structural, wide band gap half-metallic, and pressure-dependent thermodynamic predictions of Li2TMMgO6 (TM = V, Nb, and Ta) double perovskites.

Li2VMgO6, Li2NbMgO6, and Li2TaMgO6 double perovskite compounds were energetically the most stable in the FM phase. The lattice constants were 7.63Å, 7.94Å, and 7.95Å, and the Curie temperatures were 910.451K, 930.739K, and 1258.821K, respectively. The wide bandgap semiconductor characters were provided in the GGA-PBE methods as 2.139eV, 4.209eV, and 5.007eV, respectively. This wide band gap semiconductor state in the majority carriers and the metallic state in the minority states made these double perovskites true half-metallic ferromagnetics. The bulk modulus obtained in the ground state calculations and the values obtained from thermodynamic calculations were relatively close. Debye temperatures in the initial state conditions were 747K, 685.13K, and 587.77K, respectively. The total magnetic moment values were calculated as 3.00 µB/f.u. The most significant contribution to this value came from oxygen atoms. The theoretical calculations of Li2VMgO6, Li2NbMgO6, and Li2TaMgO6 double perovskite alloys were performed using the WIEN2k program developed by Blaha et al. The electronic calculations were made with GGA-PBE, GGA + mBJ, and GGA + U approximations in the space number 225 and the Fm-3m symmetry group. The thermodynamic calculations were performed using Gibbs2. In thermodynamic calculations, temperature increases were determined as 100K and temperature values were increased from 0 to 1200K.

Electronic structure and magnetothermal properties of two-dimensional ScCl.

Two-dimensional ferromagnetic materials with intrinsic half-metallic properties have strong application advantages in nanoscale spintronics. Herein, density functional theory calculations show that monolayer ScCl is a ferromagnetic metallic material when undoped (n = 0), and the transition from metal to half-metal occurs with the continuous doping of holes. On the contrary, as the concentration of doped electrons increases, the system will exhibit metallic characteristics, which is particularly evident from a variation in spin polarizability. Furthermore, we have discussed how doped carriers affect the shape of the Fermi surface and the Fermi velocity of electrons. Most importantly, Monte Carlo simulations show that the ScCl monolayer is particularly regulated by carrier concentration (n) and magnetic field (h). Additionally, trends in energy and magnetic exchange coupling in different magnetic configurations (AFM phase and FM phase) with different doping concentrations are presented. When n < -0.16, the material is not only a half-metallic material that easily flips the magnetic axis, but also proves to be a candidate ferromagnetic material that works stably at room temperature in terms of dynamic stability. In addition, the origin of magnetocrystalline anisotropy is analyzed, and the contribution of different orbitals to spin-orbit coupling is presented. Moreover, we note that when magnetic field is small (h < 1 T), the change in size has a significant effect on ferromagnetic phase transition. However, when the system size is large (size >15 nm), TC is less sensitive to magnetic field. In addition, hole doping and size effect will greatly affect the hC of the system, but when the hole doping exceeds the critical value (n = -0.16), its influence on the hysteresis loop is no longer obvious. These interesting magnetic phenomena and easily adjustable physical properties show us that monolayer ScCl will be a promising functional material.

Effects of applied different potentials on electronic and Half-Metallic characteristics and investigated Pressure-Dependent elastic and thermodynamic properties of VRu2Br4 spinel

The electronic and half-metallic characteristics and the pressure-dependent elastic and thermodynamic properties of VRu2Br4 spinel were calculated using different potentials. Firstly, the magnetic phases of VRu2Br4 spinel were investigated, and the FM phase was obtained as more stable than the AFM and NM phases. The lattice parameter and magnetic moment obtained at this stability are 10.93 Å and 10.00 µB/f.u, respectively. The most magnetic contribution came from V with 2.302 µB. Then the electronic calculations are performed by applying the GGA + mBJ and GGA + U (U = 1, 2, and 3 eV) potentials. While the energy gap is obtained as 0.210 eV in the GGA method, these are obtained as 1.282 eV, 0.693 eV, 1.200 eV, and 1.718 eV at GGA + mBJ, GGA + 1 eV, GGA + 2 eV, and GGA + 3 eV, respectively. The elastic calculation results show that VRu2Br4 spinel is stable. While the bulk, shear, and Young’s modulus values increase with the applied pressure, the B/G and Poisson’s ratios decrease. At 0 GPa pressure, the B/G and Poisson’s ratios were obtained as 2.48 and 0.322, respectively. Therefore, spinel shows ductile properties at 0 GPa pressure. These values were 1.75 and 0.26, respectively, at 10 GPa pressure. These results are boundary conditions for the brittleness and ductility properties of materials. Therefore, VRu2Br4 spinel starts to show a brittle character with increasing pressure. According to its thermodynamic properties, at 0 GPa pressure and 0 K temperature, Debye temperature is 257.22 K, while the Uvib, and Fvib energy values are 33.683 kJ/mol.

Structural, elastic, mechanical, electronic, and magnetic properties of In2NbX6 (X = Cl, Br) variant perovskites

AbstractThis article is about the study of structural, elastic, mechanical, electronic, and magnetic properties of two variant perovskites In2NbX6 (X = Cl, Br) using density functional theory. To the best of our information all calculations were carried out for the first time. The results established the cubic state stability of the present compounds in the FM phase. The thermodynamic and perovskites phase stabilities are respectively confirmed from negative values of formation energies and tolerance factor. The calculated elastic constants C11, C12, and C44 confirmed the mechanical stability of In2NbX6 compounds. The mechanical properties confirmed ductile nature of In2NbCl6 and brittle nature of In2NbBr6. The electronic properties showed that these compounds were metallic in spin up state and semiconductor in spin down state. The magnetic moments were calculated as 1 μB for both the compounds majorly associated with the Nb atom. The spin dependent electrical conductivity was calculated via BoltzTrap code. Besides half metallic nature, high spin dependent electrical conductivities reveals that In2NbX6 variant perovskites compounds are suitable for spintronic applications.

Electronic, magnetic, half-Metallic, pressure-induced elastic and curie temperature predictions of Zr2RhTl Heusler alloy: DFT and EFT studies

ABSTRACT The DFT method investigated the total and partial magnetic moments, half-metallic characters, and pressure-dependent elastic properties of Zr2RhTl alloy. According to the ground state properties, the FM phase is more stable in energy than the AFM and NM phases. The Curie temperature value was obtained as 897.43 K with the help of the energy differences of the AFM and FM phases. The total magnetic moment of Zr2RhTl alloy was obtained as 2.00 µB/f.u. Partial magnetic moment values were obtained as 0.810, 0.506, 0.032, and 0.009 µB for Zr1, Zr2, Rh, and Tl atoms, respectively. All these total and partial magnetic moment values and Curie temperatures were supported by the Effective Field Theory (EFT) method. In addition, partial Curie temperatures of Zr2RhTl alloy were calculated by EFT separately for each element. The up-spins of Zr2RhTl alloy show metallic character in both the GGA and GGA + mBJ approximations, while the down-spins have band gaps of 0.698 and 0.699 eV, respectively. Electronic properties were also supported by GGA + U (U = 1, 2, 3 eV) interactions. Therefore, Zr2RhTl alloy is a true half-metallic ferromagnetic material. Zr2RhTl alloy was elastically stable, and the Debye temperature was calculated as 221.496 K at 0 GPa. All calculations obtained using two different methods (DFT and EFT) and two different approximations (GGA and GGA + mBJ) support each other. Therefore, Zr2RhTl alloy proved to be a very suitable material to be used as an alternative for spintronics.

Giant magnetothermal anomalies and direct measurements of the magnetocaloric effect in Pr0.7Sr0.3−xBaxMnO3 manganites

The paper presents the results of a study of magnetization, specific heat (CP), thermal diffusivity (η), thermal conductivity (κ) and direct measurements magnetocaloric effect of polycrystalline samples Pr0.7Sr0.3−xBaxMnO3 (x = 0–0.3). An increase in the Ba concentration leads to a decrease in the Curie temperature (TC), an increase in the disorder parameter (σ2) and a noticeable increase in thermal conductivity of the ferromagnetic phase (FM). The κ(Т) data near ТС revealed small minima and a sharp jump-like change in thermal conductivity upon transition to the FM phase. These results suggest that the anomalies in the temperature dependences of η(Т) and κ(Т) are associated with the scattering of thermal phonons both from distortions of the crystal lattice and from spin fluctuations. The giant change of η (Δη/η ∼ 67%) and κ (Δκ/κ ∼ 33%) was found in a magnetic field of 1.8 T for the x = 0 (Pr0.7Sr0.3MnO3) sample. The maximum values of ∆T, ∆S and relative cooling power (RCP), observed for this sample in a field of 1.8 T, are equal to 1.81 K, 3.38 J/kg K and 74.02 J/kg, respectively. In the studied Pr0.7Sr0.3−xBaxMnO3 samples, the specific cooling power value at f = 0.2 Hz is 0.35, 0.29, 0.21, and 0.11 W/g for x = 0, 0.1, 0.2, and 0.3 sample, respectively.

Calculation of magnetocaloric effect with regard for dependence of heat capacity on magnetic field

A specific heat of the magnetic solid exhibiting AFM–FM phase transition is computed using the Landau-type theory of phase transitions. The experimentally observed dependence of the specific heat value on the external magnetic field is modelled. It is shown, that this dependence has strong influence on the giant magnetocaloric effect (MCE), which is inherent to the solids exhibiting the phase transitions accompanied by the strong change of magnetization value: the disregard of this dependence leads to the noticeable overestimation of adiabatic temperature change, which is the practically important characteristic of MCE. The temperature change characterizing the giant MCE observed in Fe–Rh alloys is computed. The reasonable agreement between the available experimental data and obtained theoretical results is demonstrated.

Magnetic domain depinning as possible evidence for two ferromagnetic phases inLaCrGe3

Two ferromagnetic phases, FM1 and FM2, were first proposed to exist in LaCrGe$_3$ based on a broad maximum in the temperature derivative of resistivity resembling that of the superconducting ferromagnet UGe$_2$ where FM1 and FM2 are well-established. While evidence for two FM phases can be found in certain additional probes, corresponding anomalies in magnetization have not been recognized until now. Our spatially-resolved images of the magnetic domains show a substantial change in the domain structure between the higher temperature FM1 phase and the lower temperature FM2 phase. Furthermore, our measurements of the coercive field and virgin magnetization curves reveal an unconventional magnetic domain pinning region in the FM1 phase, followed by a depinning region at lower temperatures where the system is reported to crossover into the FM2 phase. We incorporate this discovery into a simple domain magnetization model that demystifies the magnetization curve seen in all previous studies. Finally, we find that the unusual domain behavior can be explained by a change in the ferromagnetic exchange interaction and magnetic moment, both of which are consistent with the existence of two FM phases. This revelation may help explain a range of anomalous behaviors observed in LaCrGe$_3$ and rekindles the discussion about the prevalence of multiple FM phases in fragile FM systems.

Magnetic-field-controlled growth of magnetoelastic phase domains in FeRh

Magnetic phase transition materials are relevant building blocks for developing green technologies such as magnetocaloric devices for solid-state refrigeration. Their integration into applications requires a good understanding and controllability of their properties at the micro- and nanoscale. Here, we present an optical microscopy study of the phase domains in FeRh across its antiferromagnetic–ferromagnetic phase transition. By tracking the phase-dependent optical reflectivity, we establish that phase domains have typical sizes of a few microns for relatively thick epitaxial films (200 nm), thus enabling visualization of domain nucleation, growth, and percolation processes in great detail. Phase domain growth preferentially occurs along the principal crystallographic axes of FeRh, which is a consequence of the elastic adaptation to both the substrate-induced stress and laterally heterogeneous strain distributions arising from the different unit cell volumes of the two coexisting phases. Furthermore, we demonstrate a magnetic-field-controlled directional growth of phase domains during both heating and cooling, which is predominantly linked to the local effect of magnetic dipolar fields created by the alignment of magnetic moments in the emerging (disappearing) FM phase fraction during heating (cooling). These findings highlight the importance of the magnetoelastic character of phase domains for enabling the local control of micro- and nanoscale phase separation patterns using magnetic fields or elastic stresses.

Structural, Thermoelectric, Electronic, and Magnetic Properties of Pristine Intermetallic Rare-Earth-Based XMn2Si2 (X=Dy, Er) Compounds

Detailed Structural, thermoelectric, electronic and magnetic properties of the ternary rare-Earth based XMn2Si2 (X=Dy, Er) Compounds, are investigated using the full-potential linearized augmented-plane wave (FP-LAPW) method with generalized gradient approximation (GGA+U) in ferromagnetic phase. The basic calculations of optimization are found with the support of (PBE-GGA) to realize theoretical consistency with existing experimental consequences, although for the enhancement of magneto-electronic part the (GGA+U) technique is employed. We have identified theoretically that the ferromagnetic is the most suitable phase among three studied phases for these compounds agree well with previous experimental works. The electronic band structure indicates that these compounds are metallic through both spin channels in the FM phase. A secure hybridization occurs between the elements Dy/Er-f and Mn-d states in the valence band and the Si-p state in the conduction band. The total magnetic moments verify that the rare-Earth based DyMn2Si2 ternary inter-metallic compound showcases stronger ferromagnetic behavior patterns than the ErMn2Si2 compound. We estimated the Seebeck coefficient S, electrical and thermal conductivities, and the ZT in this study over the temperature range of 0 to 800 K. The ErMn2Si2 is a viable contender for high-temperature applications in waste heat management because of its high ZT values in the high-temperature region in thermoelectric devices.

Distinct Magnetic Gaps between Antiferromagnetic and Ferromagnetic Orders Driven by Surface Defects in the Topological Magnet MnBi_{2}Te_{4}.

Many experiments observed a metallic behavior at zero magnetic fields (antiferromagnetic phase, AFM) in MnBi_{2}Te_{4} thin film transport, which coincides with gapless surface states observed by angle-resolved photoemission spectroscopy, while it can become a Chern insulator at field larger than 6T (ferromagnetic phase, FM). Thus, the zero-field surface magnetism was once speculated to be different from the bulk AFM phase. However, recent magnetic force microscopy refutes this assumption by detecting persistent AFM order on the surface. In this Letter, we propose a mechanism related to surface defects that can rationalize these contradicting observations in different experiments. We find that co-antisites (exchanging Mn and Bi atoms in the surface van der Waals layer) can strongly suppress the magnetic gap down to several meV in the AFM phase without violating the magnetic order but preserve the magnetic gap in the FM phase. The different gap sizes between AFM and FM phases are caused by the exchange interaction cancellation or collaboration of the top two van der Waals layers manifested by defect-induced surface charge redistribution among the top two van der Waals layers. This theory can be validated by the position- and field-dependent gap in future surface spectroscopy measurements. Our work suggests suppressing related defects in samples to realize the quantum anomalous Hall insulator or axion insulator at zero fields.

Room Temperature Ferromagnetic Properties of Ga14N16−nGd2Cn Monolayers: A First Principle Study

Electronic and magnetic properties of Ga14N16−nGd2Cn monolayers are investigated by means of the first principle calculation. The generalized gradient approximation (GGA) of the density functional theory with the on-site Coulomb energy U was considered (GGA + U). It is found that the total magnetic moment of a Ga14N16Gd2 monolayer is 14 μB with an antiferromagnetic (AFM) phase. C atom substitutional impurity can effectively change the magnetic state of Ga14N16−nGd2Cn monolayers to ferromagnetic phases (FM), and the magnetic moment increases by 1μB/1C. The stable FM phase is due to the p-d coupling orbitals between the C-2p and Gd-5d states. Moreover, Curie temperature (TC) close to room temperature (TR, 300 K) is observed in the Ga14N16Gd2C2 monolayer, and the highest value can reach 261.46 K. In addition, the strain effect has a significant positive effect on the TC of the Ga14N16−nGd2Cn monolayer, which is much higher than the TR, and the highest value is 525.50 K. This provides an opportunity to further explore the application of two-dimensional magnetic materials in spintronic devices.

First principles investigation on half metallic ferromagnetism properties of cubic VLaO3 compound

In this investigation, we thoroughly examined the equilibrium structural, electrical, magnetic, elastic, thermodynamic, as well as thermoelectric behavior of the vanadium lanthanum oxide perovskite VLaO3. The computations were executed with the FP-LAPW method, as in cooperated in the WIEN2k package that rely on the first principles method, using generalized gradient approximation (PBE-GGA). The explored compound has been observed to be ferromagnetically stable i.e., in FM phase as it has lowest energy in FM state than in paramagnetic phase i.e., in NM phase. The thermodynamical and mechanical stability of the studied VLaO3 compound is also assured by evaluating its formation energy, cohesive energy and second order elastic constants. Furthermore, our computed findings reveal that the studied compound belongs to half metallic perovskites with an energy gap of 2.56 eV in the majority spin and possesses a total magnetic moment of 3.99µB/unit cell. Additionally, the thermal as well as pressure dependence of volume, specific heat capacity, and bulk modulus are also examined with the aid of GIBBS which rely on quasi harmonic Debye theory. Finally, the thermoelectric transport properties are also evaluated as a function of chemical potential in the range extending from −2.0 eV to 2.0 eV for different temperatures at 300 K, 700 K and 1200 K to explore budding possibility of this compound for energy harvesting applications.

Irreversible metamagnetic behaviors and H-T phase diagram in phase separated La0.5Ca0.5Mn1-xAlxO3-δ

Magnetization relaxation, ac susceptibility, dc magnetization and magnetoelectrical transport measurements have been carried out on Al3+-doped manganites La0.5Ca0.5Mn1-xAlxO3-δ (x = 0.05, 0.07, 0.09, 0.10, 0.15). Experimental results suggest that nonmagnetic Al3+ substituting Mn suppresses the ferromagnetic phase and induces a charge ordered antiferromagnetic phase. The coexistence and competition of these two kinds of interactions result in a spin-glass like state in x = 0.1 and 0.15 system. Obvious hysteresis was observed in both magnetization and resistivity versus temperature and magnetic field curves, suggesting an inhomogeneous metastable phase transition. Upon applying a magnetic field of HCA-F, the Al3+-doped samples undergo an irreversible metamagnetic transition from the charge ordering antiferromagnetic insulating to ferromagnetic metallic phase in the low temperature region. Phase diagram in the HC-T plane has been determined according to the magnetization and magnetoelectric transport measurements. The magnetic disorders and antiferromagnetic matrix produced by Al3+ dopants and spontaneous oxygen vacancies play an important role in the pinning of the FM phase.

Interfacing between FM and project phases through digital processes and collaborative practices

Challenges and opportunities of creating value through information delivery from renovation projects to Facility Management is an ongoing issue for the built environment. Eight interviews were conducted with FM, project management and construction management involved in renovation projects to examine this issue closely. The finding support existing work from new project delivery in the need for ongoing coordination of information flows between projects and FM. However, there is less understanding on how this information is integrated into FM practices and the role of FM in project processes in creating long-term value of renovated buildings. The outcome is that there is a to incorporate FM into the current framework of project process as a continuous role to ensure FM knowledge is embedded in data systems. Both coordination processes and clear communication interactions is required to build meaning into data that can be adapted to different knowledge discipline bases working in different times and contexts across the building lifecycle. The research is relevant to practitioners and educators on illustrating how FM need to evolve and engage/be invited into projects decision-making that has long-term implication for FM services and digital systems throughout the building life-cycle.

Spin-lattice coupling in magnetocaloric Gd5(Ge,Si)4 alloys by $in$ $situ$ x-ray pair distribution analysis in magnetic field

Using in situ x-ray pair distribution analysis in magnetic field, we study the strong spin-lattice coupling in archetypal magnetocaloric ${\mathrm{Gd}}_{5}{(\mathrm{Ge},\phantom{\rule{0.28em}{0ex}}\mathrm{Si})}_{4}$ alloys manifested by the presence of a first order paramagnetic (PM)-to-ferromagnetic (FM) phase transition that can be triggered by either decreasing temperature in zero magnetic field or increasing magnetic field at constant temperature. We find that the coupling arises from the tendency of Gd-(Si,Ge) slabs in the alloys to reversibly slide against each other to both pack closely and couple ferromagnetically. We also find that, locally, the packing of slabs in FM phases induced by decreasing temperature in zero field is different from that in FM phases of the same chemical composition induced by increasing magnetic field isothermally, indicating that temperature and magnetic field are coupled but not necessarily equivalent control variables for triggering phase transitions in strongly correlated systems.

Evidence of structural and two magnetic phase transitions in Cu doped La2FeMnO6 double perovskites

In this report, we have addressed a comprehensive study on the structural phase transitions with the help of a combination of high temperature x-ray diffraction and temperature dependence Raman spectroscopy. We also report the magnetic ground state of all the samples at room temperature and 5 K. The combined high temperature x-ray diffraction and temperature dependence Raman study suggests that the samples undergo structural phase transitions from orthorhombic to tetragonal to cubic dominated mixed phase. With the help of x-ray photoelectron spectroscopy, we confirmed the presence of multi-oxidation states of Fe and Mn ions. The temperature evolution of magnetization data has been recorded at a field of 100 Oe and temperature range between 2 K and 300 K, and reveals the presence of two magnetic phase transitions for pristine, 10% and 20% doping of Cu in the composition La 2 FeMn 1−x Cu x O 6 . The magnetic study of all the samples reveal that the magnetic ground state of all the samples shows paramagnetic nature at room temperature, whereas at lower temperature all the samples are ferromagnetic except the highest doped sample which is purely paramagnetic. The law of approach to saturation method is imposed in the saturation region of M-H curve observed at 5 K. The transition temperature decreases with the amount of Cu doping, due to the substitution of Cu in Mn-site resulting in destroy of the Mn 3+ -O 2- - Mn 4+ bridges which is responsible for weakening of double exchange interaction between Mn 3+ and Mn 4+ . • Temperature dependent XRD has shown a structural phase transition from orthorhombic to tetragonal to cubic space group. • Temperature evolution of the phononic modes predominantly influenced by the lattice degrees of freedom. • Magnetic studies have shown two phase transitions confirming low temperature FM phase with different ordering mechanisms.

Dynamical quantum phase transition in periodic quantum Ising chains

The dynamical quantum phase transitions (DQPTs) after a sudden quench in periodic quantum Ising chains (QICs) are studied. We obtain the formulas of the Loschmidt echo and the Fisher zeros of the Loschmidt amplitude in the periodic QIC. It is found that for the quench across the quantum phase transitions (QPTs), the periodic QICs have richer DQPTs than that in the homogeneous QIC, and the number of critical times of the DQPTs are dependent on the specifical parameter of the pre- and post-quench Hamiltonian. For instance, in the period-two QIC, there is one critical time for the quench from the FM phase to the PM phase, and three critical times for the quench from the PM phase to the FM phase. In the period-three QIC, there may have three or four critical times for the quench from FM phase to the PM phase, but may have two or three critical times for the quench from PM to the FM phase. The reason is that the periodic QICs have multiple quasiparticle excitation spectra, and the Fisher zeros of the periodic systems consist of several separated branches, which is different from that in the homogeneous QIC. For different quenches across the QPTs, different branches will intersect with the imaginary axis, which correspond to different critical times. Our conclusion also provides insight in the property of the DQPT in the inhomogeneous systems.

Direct and inverse magnetocaloric effects in FeRh alloy

There are two types of magnetocaloric effects that are the so-called direct and inverse effects originating from ferromagnetic–paramagnetic (FM–PM) and antiferromagnetic–ferromagnetic (AFM–FM) phase transitions, respectively. Here, the magnetocaloric effects of FeRh alloy, which exhibit both the direct and inverse effects, have been studied by combining first-principles calculations and Monte Carlo simulations. The magnetic exchange coupling constants in the AFM and FM phases are evaluated by first-principles calculations based on the Liechtenstein formula. The Monte Carlo calculations considering the two-phase mixtures of AFM and FM well reproduce the experimental magnetization curves at zero external magnetic field. It is also shown that the isothermal magnetic entropy changes near the AFM–FM transition temperature under magnetic fields are successfully reproduced based on the Maxwell relation. The entropy changes in a wide range of the magnetic fields near the AFM–FM and FM–PM transition temperatures are investigated and the direct and inverse magnetocaloric effects of FeRh are discussed. The giant relative cooling power of FeRh alloy is achieved due to the large saturation magnetizations and the first-order AFM–FM phase transition.