Relative Cooling Power Values Research Articles

First-order phase transition in perovskites Pr0.67Sr0.33MnO3 – magneto-caloric properties – effect of multi-spin interaction

We show by extensive Monte Carlo simulations that we need a multi-spin interaction in addition to pairwise interactions in order to reproduce the temperature dependence of the experimental magnetization observed in the perovskite compound Pr0.67Sr0.33MnO3. The multi-spin interaction is introduced in the Hamiltonian as follows: each spin interacts simultaneously with its four nearest-neighbors. It does not have the reversal invariance as in a pairwise interaction where reversing the directions of two spins leaves the interaction energy invariant. As a consequence, it competes with the pairwise interactions between magnetic ions. The multi-spin interaction allows the sample magnetization M to increase, to decrease or to have a plateau with increasing T. In this paper we show that M increases with increasing T before making a vertical fall at the transition temperature TC, in contrast to the usual decrease of M with increasing T in most of magnetic systems. This result is in an excellent agreement with the experimental data observed in Pr0.67Sr0.33MnO3. Furthermore, we show by the energy histogram taken at TC that the transition is clearly of first order. We also calculate the magnetic entropy change |ΔSm| and the Relative Cooling Power (RCP) by using the set of curves of M obtained under an applied magnetic field H varying from 0 to 5 T across the transition temperature region. We obtain a good agreement with experiments on |ΔSm| and the values of RCP. This perovskite compound has a good potential in refrigeration application due to its high RCP.

Structural, magnetic and magnetocaloric properties of Li-substituted La0.8K0.2-xLixMnO3 perovskite manganites

In this study we report the effect of lithium substitution on the structural, magnetic and magnetocaloric properties of La0.8K0.2-xLixMnO3 (0 ≤ x ≤ 0.075) samples synthesized by the sol–gel technique at low temperature. The investigated compounds crystallize in a rhombohedral system with R3¯c space group. The thermal variation of the magnetization under an applied magnetic field of 0.05 T showed that all our compounds exhibited a paramagnetic to ferromagnetic transition with decreasing temperature. With increasing lithium content, the Curie temperature TC, decreases from 287.4 K for x = 0 to 172.6 K for x = 0.075. The maximum of the magnetic entropy change, -ΔSMMax, is found to be 3.19, 3.51, 2.39 and 2.24 J kg−1 K−1 in a magnetic field change of 5 T for x = 0, 0.025, 0.05 and 0.075 respectively. The La0.8K0.175Li0.025MnO3 sample displays a higher maximum relative cooling power value of 320.5 J kg−1, equal to 78 % of that of gadolinium. Technically, this large value associated to a TC of 270 K makes the present sample very promising for magnetic refrigeration technology below room temperature.

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.

Estimation on magnetic entropy change and specific heat capacity through phoenomological model for Heusler melt spun ribbon of Ni47Mn40−x Si x In3 (x = 1, 2 and 3)

Abstract In this, we report the temperature-dependent magnetization [M(T)] in two distinct magnetic fields of 0.5 T and 5 T for Ni47Mn40−x Si x In3 (x = 1, 2, and 3) alloys. Using a phenomenological model and Maxwell’s thermodynamic relation, the values of the magnetic entropy change and specific heat capacity are calculated, and their values are also compared. The maximum magnetic entropy change and specific heat capacity peak values for different magnetic fields are both steadily reduced for the samples with x = 1 to 3 samples, which is followed by an increase in relative cooling power value. In comparison to 0.5 T magnetic field, the samples investigate the highest values of magnetic entropy change (3.32, 2.81, 2.01 J kg−1 K−1) and specific heat capacity (32.37, 14, 4.32 J kg−1 K−1) with a magnetic field of 5 T. According to this finding, the sample is more responsible for the magnetic field than chemical pressure.

Magnetocaloric effect in aluminum doped ErCr1−xAlxO3 orthochromites

Aluminum-doped ErCr1-xAlxO3 orthochromites prepared via autocombustion technique were investigated for their magnetic and magnetocaloric properties. X-ray diffraction confirmed that samples were orthorhombic phases with the Pbnm space group without a trace of any impurity. As analyzed via Rietveld refinement of XRD data, structural parameters such as lattice parameters, volume, bond angle, and bond lengths were affected by doping nonmagnetic Al3+ in the compound. ErCrO3 possesses the long-range antiferromagnetic ordering with a weak display ferromagnetism at TN =133 K. Low-temperature high-field magnetic study shows a decrease in Neel temperature (TN ∼ 114 K for x = 0.5), suggesting magnetic ordering suppression due to Al3+ doping. The asymptotic paramagnetic Curie temperature Tcw = −25 K suggests the predominance of antiferromagnetic interactions in ErCrO3 orthochromites, which was observed to increase with Al3+ doping. Isothermal magnetization data show changes in magnetic entropy (−ΔSMmax) and relative cooling power (RCP). The magnetic entropy change, −ΔSMmax, for ErCrO3 estimated from magnetization measurements show 11.60 J kg−1 K−1 at 11 K and a relative cooling power (RCP) of 209.4 J kg−1 at 5 T applied field. While ErCr0.75Al0.25O3 show a maximum magnetic entropy of 11.52 J kg−1 K−1 at 11 K with a 5 T applied field and RCP of 186.66 J kg−1, whereas ErCr0.5Al0.5O3 displayed −ΔSMmax of 11.63 J kg−1 K−1 at 5 K with a 5 T applied field and RCP value of 160.78 J kg−1. The results show that nonmagnetic doping, such as Al3+, could maintain the compound’s magnetocaloric property to an extent.

DFT and Monte Carlo investigations of electronic structure, magnetic, magnetocaloric, and thermoelectric properties of the perovskite SrXO3 (X = Mn and Fe) compound

The structural, electronic, magnetic, magnetocaloric, and thermoelectric properties of the SrXO3 (X = Mn and Fe) perovskite compounds were investigated using first-principles calculations. It was observed that the SrXO3 compounds are G-anti-ferromagnetic perovskites with partial magnetic moment with a value of 2.7 [Formula: see text] and 2.4 [Formula: see text] for Mn-3d and Fe-3d orbitals for SrMnO3 and SrFeO3, respectively. Moreover, by using Monte Carlo simulation (MCs) combined with the Metropolis algorithm, the calculated coupling interactions between the magnetic atoms Mn–Mn and Fe–Fe are [Formula: see text][Formula: see text]meV and [Formula: see text][Formula: see text]meV for SrMnO3, [Formula: see text][Formula: see text]meV and [Formula: see text][Formula: see text]meV for SrFeO3, respectively. Furthermore, a significant magnetocaloric effect (MCE) was observed around the Néel temperature of [Formula: see text][Formula: see text]K (for SrMnO3) and [Formula: see text][Formula: see text]K (for SrFeO3), and the maximal simulated magnetic entropy and relative cooling power values of all the studied compounds are found to be 100[Formula: see text]J/kg (for SrMnO3) and 110[Formula: see text]J/kg (for SrFeO3), respectively, with an applied magnetic field of [Formula: see text] T. These results are in complete agreement with the experimental results and more specifics than other theoretical calculations. Hence, SrXO3 compounds are considered promising candidates for magnetic refrigeration at low temperature.

Observation of Griffiths phase, spin glass behaviour and magnetocaloric effect in frustrated Ga2Mn2-xCrxO7 (x = 0, 0.1, 0.3, 0.5) pyrochlore compounds

New series of pyrochlore compounds Ga2Mn2-xCrxO7 (x = 0–0.5) has been synthesized by conventional solid-state reaction method. The X-ray diffraction analysis confirms a single-phase cubic structure of the prepared compounds. All compounds undergo a paramagnetic-antiferromagnetic transition at the Néel transition temperature, close to 42 K. Below ∼12 K temperature, magnetization measurements reveal a glassy behaviour. The value of frustration parameter indicates the presence of a spin frustration. All the compounds exhibit the Griffiths phase. The Arrott's plots confirmed a second-order magnetic phase transition. Moreover, under 5 T applied magnetic field, the maximum value of magnetic entropy change −ΔS was 1.36 J/kg.K for Ga2Mn2O7 compound, which slightly increased to 1.47 J/kg.K for the compound with x = 0.5. At 21 K, the relative cooling power value enhanced from 42.96 J/kg to 47.73 J/kg with Cr4+-ion content changing from x = 0 to x = 0.5.

Effects of Ca substitution on magnetic and magnetocaloric properties in PrBa1-xCaxMn2O6 system

In this study, we have examined the effect of Ba substitution by Ca on the magnetic, and magnetocaloric properties of PrBa1-xCaxMn2O6 (x = 0, 0.2 and 0.3) double perovskite manganites produced using sol-gel method. The samples were indexed in orthorhombic structure (with space group of Pbnm). The temperature-dependent magnetization, M(T), measurements indicate that all samples have a magnetic phase transition from ferromagnetic (FM) to paramagnetic (PM) state with increasing temperature. Curie temperature (TC) decreases with increasing Ca content in the main lattice. From the magnetic field dependence of magnetization measurements, M(H), maximum magnetic entropy change (−ΔSMmax) values were calculated as 4.07, 4.12, and 5.04 Jkg−1K−1 under 5 T for PrBaCaMn2O6, PrBa0.8Ca0·2Mn2O6, and PrBa0.7Ca0·3Mn2O6 samples, respectively. Relative cooling power (RCP) values below 5 T were determined as 214.16, 227.14 and 279.62 Jkg-1 based on the increasing Ca content. The −ΔSMmax and RCP values enhance with increasing Ca content, respectively. The nature of the phase transition, checked by Banerjee criterion and Franco's universal master curves, was found to be second order magnetic phase transition (SOMT).

Insight into the structural and magnetic properties of RECo12B6 (RE = Ce, Pr, Nd) compounds: A combined experimental and theoretical investigation

Rare earth (RE) based RE-TM-X (TM = transition metal elements; X = P-block elements) materials have received continuous attention due to the exhibition of various intriguing magnetic functional characteristics. In this work, a combined experimental and theoretical investigation has been conducted in detail for RECo12B6 (RE = Ce, Pr, Nd) compounds with regard to their structural and magnetic properties, particularly the magnetocaloric effect and magnetic phase transition (MPT). All of the present RECo12B6 compounds are found to crystalize in the SrNi12B6-type structure and with a ferrimagnetic ground state, which is confirmed by density functional theory calculations and magnetization measurements. The magnetic moments of RE atoms and Co atoms tend to be in antiparallel alignment, and the MPT of these materials originates primarily from the spin-polarized 3d electrons of the Co atoms, which can be greatly affected by the 4f electrons of RE atoms. Considerable magnetocaloric effects have been observed around its own TC of 130, 157, and 160 K, for CeCo12B6, PrCo12B6, and NdCo12B6, respectively, which is related to a typical second-order MPT. The corresponding maximum magnetic entropy change and relative cooling power values,with field changes of 0–70 kOe, are determined to be 2.54, 2.84, and 2.77 J/kg K and 116.8, 156.2, and 155.1 J/kg, respectively. The MPT properties of present RECo12B6 compounds were studied in further detail by critical analysis using the modified Arrott Plot and Kouvel-Fisher methods, which can be explained within the frame of the 3D Heisenberg model with short-range magnetic interaction.

Ionic radius effect on the evolution of the griffiths phase and the magnetocaloric response at low temperature of A2Mn2O7 (A: Fe, Al and La)

In the present paper a comparative research study has been conducted on the magnetic and magnetocaloric response of the materials of A2Mn207 (A: Fe, Al and La) oxides. . The XRD refinement analysis suggests that the A2Mn207 oxides are crystallized in monoclinic structure with space group P2/m. The thermal evolution of the magnetization reveals a ferromagnetic transition and a presence of a Griffith's phase at low temperature. A2Mn207 oxides exhibit a clear correlation between the ionic radius rA3+, in the A-site, and the magnetic transition temperature and that of Griffiths. However, this correlation is not obvious for the value of the universal exponent λ. In addition, the current study reveals an increase in the Relative Cooling Power (RCP) value with a decrease in ionic radius. Furthermore, the magnetocaloric effect (MCE) value, has been found to be exploited over a wide temperature range by increasing the cationic radius rA3+.

Topotactic synthesis of DyVO3; an investigation of magnetocaloric effect

The orthovanadate DyVO3 has been synthesized by reducing DyVO4 in H2 environment. The material crystallizes in an orthorhombic crystal structure at room temperature (space group Pbnm). The antiferromagnetic transition of the vanadium sublattice is observed near 114 K. The effect of an external magnetic field on spin re-arrangement in the vanadium sublattice has been studied. The magnetic entropy change has been calculated from the isothermal magnetization measured in the magnetic field 0–5 T. At 2 K, the M−H isotherm saturates with the increasing magnetic field. The maximum magnetic entropy change (-ΔSMmax) has been estimated to be 12.9 J kg−1 K−1 at an applied external magnetic field of 5 T around 17 K, and a relative cooling power ∼ 348 J/kg. The maximum entropy change occurs around the ordering temperature of the Dy-sublattice. The significant -ΔSMmax and relative cooling power values suggest it to be a better magnetocaloric material than several other polycrystalline perovskite compounds.

Effect of Metal-Oxide Phase on the Magnetic and Magnetocaloric Properties of La0.7Ca0.3MnO3-MO (MO=CuO, CoO, and NiO) Composite

The study reports the synthesis and characterization of the magnetic and magnetocaloric effects of metal-oxide (MO) modified La0.7Ca0.3MnO3 perovskites manganite. The powder composite samples, with a nominal composition of (1 − x)La0.7Ca0.3MnO3-xMO (Wt.% x = 0.0, 2.5, 5.0), were prepared using the facile autocombustion method, followed by an annealing process. The phase purity and structure were confirmed by X-ray diffraction. Temperature and field-dependent magnetization measurements and Arrott analysis revealed mixed first- and second-order phase transition (ferromagnetic to paramagnetic) in composite samples. The phase transition temperature shifted to lower temperatures with the addition of MO in the composite. A large magnetic entropy change (4.75 JKg−1K−1 at 1T and 8.77 JKg−1K−1 at 5T) was observed in the La0.7Ca0.3MnO3 (LCMO) sample and was suppressed, due to the presence of the MO phase in the composite samples. On the other hand, the addition of MO as a secondary phase in the LCMO samples enhanced their relative cooling power (RCP). The RCP of all composite samples increased with respect to the pristine LCMO, except for LCMO–5%NiO. The highest RCP value of 267 JKg−1 was observed in LCMO–5%CuO samples, which was 23.4% higher than the 213 JKg−1 observed for the pure LCMO at a magnetic field of 5T. The enhanced RCP of these composites makes them attractive for potential refrigeration applications.

Room temperature magnetocaloric effect in CrTe1−xSex alloys

In this work, we report room temperature magnetocaloric properties in CrTe1−xSex (0.00 ≤ x ≤ 0.10) alloys prepared by a conventional solid-state reaction. The Rietveld refinement of the XRD pattern of CrTe1−xSex showed the emerging of pure hexagonal NiAs structure with P63/mmc (194) space group with increasing Se substitution. Upon μ0H = 5 T applied magnetic field, the magnetocaloric effect analysis revealed maximum magnetic entropy change $$(\Delta {S}_{M})$$ in the range 7.9–9.2 J/kg K−1 with a relative cooling power (RCP) value of about 550–694 J/kg. The RCP values exceed the corresponding RCP value of the prototype Gd element near room temperature. The obtained results suggest that CrTe1−xSex (0.00 ≤ x ≤ 0.10) alloys is a viable candidate for a room temperature magnetic cooling application.

Strain engineering of magnetocaloric effect in W/Gd/W/MgO structures

Strain controlled magnetocaloric effect (MCE) accompanying a transition between ferromagnetic and paramagnetic phases has been revealed in multilayered W/Gd/W/MgO structures at Tc = 293 K. Mechanical stresses at the Gd/W interface controlled by internal stresses at the MgO substrate and depending on its crystallographic orientation, strongly affect magnetic part of entropy ΔSM and relative cooling power (RCP). Increase in thickness of Gd films from 100 nm up to 300 nm approaches the ΔSM and RCP values to those known for the bulk Gd samples. We found that higher internal stresses widen the temperature range in which a ferromagnet-paramagnet transition occurs. Since Gd based alloys are very perspective for magnetic refrigeration, obtained data can be used to predict how local internal stresses in the vicinity of structural defects (dislocations, twins etc) can affect MCE even in bulk Gd samples.

Magnetic and magnetocaloric properties of the double perovskite Sm-doped Ho2CoMnO6

The polycrystalline compounds Ho2-xSmxCoMnO6 (0 ≤ x ≤ 1) was synthesized by the conventional solid-state process. The structural study has been solved by X-ray powder diffraction (XRD) indicating that all studied samples adopt a monoclinic structure with the space group P21/n. The magnetic properties of the Ho2-xSmxCoMnO6 (0 ≤ x ≤ 1) compounds, show a ferromagnetic transition at the Curie temperature (TC), thus the latter increases with Sm doping. Finally, the magnetocaloric effect (MCE) study revealed that the maximum magnetic entropy change (-ΔSM)max, at TC under a magnetic-field-change (h = μ0ΔH) of 5 T, decreases with Sm doping from 4.97 to 1.86 J kg−1 K−1 for x = 0 to x = 1, respectively. The results show that Sm doping increases TC but lowers the magnetocaloric response, but obtained values of Relative Cooling Power (RCP) and adiabatic temperature (ΔTad) remain reasonably high. Hence, the investigated compounds, given their high stability and eco-friendly, could be promising materials for magnetic refrigeration technology.

Structural, magnetic and magnetocaloric properties of the rare earth (RE) molybdate RE2MoO6 (RE = Dy, Tb and Gd) oxides

Reported here is a systematical investigation on the crystal structure, magnetic properties and magnetocaloric (MC) effect of three rare earth (RE) molybdate RE2MoO6 (RE = Dy, Tb and Gd) oxides. The X-ray powder diffraction and the morphology as examined using the scanning electron microscope indicate phase-pure and polycrystalline nature of these oxides. The temperature (2–100 K) and magnetic field (up to 5 T) dependence of the magnetic measurements determine the magnetic phase transition (MPT) and MC properties. All the present RE2MoO6 oxides crystallize in a monoclinic structure belonging to C2/c space group with the antiferromagnetic ordering at low temperature. Moreover, the RE2MoO6 oxides hold reasonable values of MC parameters including the maximum isothermal magnetic entropy change/temperature-averaged entropy change (2 K lift) and relative cooling power values have been evaluated with the magnetic change of 0–5 T, yielding 17.22 (17.08) J/kgK and 277.67 J/kg for Dy2MoO6, 17.03 (16.83) J/kgK and 261.12 J/kg for Tb2MoO6, as well as 27.68 (26.69) J/kgK and 228.14 J/kg for Gd2MoO6, respectively. These acceptable MC parameters make the present RE2MoO6 oxides potential candidates for cryogenic magnetic refrigeration (MR).

Structural, magnetic, and magnetocaloric properties of La0.7Sr0.2Nd0.1Mn1-xNixO3 (x= 0.05, 0.10, and 0.15): B-site doping

In this study, La0.7Sr0.2Nd0.1Mn1-xNixO3 (x = 0.05, 0.10, 0.15) systems were synthesized following the sol-gel (SG) approach and their structural, magnetic, and magnetocaloric characteristics were determined. The X-ray Diffraction (XRD) patterns revealed that all samples were in the R-3c space group. Magnetic studies revealed that an increase in the Ni2+ dopant resulted in a ferromagnetic (FM) to paramagnetic (PM) transition near the Curie temperature (Tc), when Tc decreased from 280 K to 220 K. The maximum change in magnetic entropy (−ΔSMMax) gradually decreased while the relative cooling power (RCP) gradually increased. The −ΔSMMax and RCP values for La0.7Sr0.2Nd0.1Mn0.95Ni0.05O3 were 4.28 J/(kg·K) and 267.67 (J/kg), respectively at 280 K when the external magnetic field variation was 5 T. This material can potentially be one of the candidates for developing the magnetic refrigeration technology.

Evaluating the properties of the intermetallic compound HoN for magnetic refrigerator application: Combined DFT and Monte Carlo simulation

Evaluating the properties of the magnetocaloric material regenerators is a crucial step in order to exploit them subsequently as the working substances in magnetic cooling devices. So, the main objective of this latter is to evaluate the electronic, magnetic properties as well as the magnetocaloric effect of HoN compound. To do so, a combination of DFT study and Monte Carlo simulations has been performed on HoN compound which undergoes a second-order ferromagnetic-paramagnetic phase transition. For this material, the temperature-dependent total magnetization, heat capacity and magnetic susceptibility have been calculated and are revealed that the curie temperature is acceptable concurrence with the experimental value. Furthermore, it was showed that under an applied magnetic field of 5T, the magnetocaloric effect (MCE) in regard to the maximum value of magnetic entropy change ΔSmagmax around its Curie temperature, agree well with the experimental one. Besides, the relative cooling power (RCP) values are found to be 28.5, 162.2 and 227 J. Kg−1 under different magnetic fields of 1,3 and 5T. All findings which are presented in the present work indicate that the large values of RCP and ΔSmagmax found in HoN are interesting for low-temperature magnetic refrigeration with excellent performance.

Theoretical study of the magnetic properties and the magnetocaloric effect in lanthanum manganite lacunar compounds

Based on the Monte Carlo method and using the Ising model, the magnetic as well as the magnetocaloric properties of lacunar compounds La1-xxMnO3 (x = 0.1 and 0.2) were investigated. Free boundary conditions for our system were applied to simulate the 3D-Ising Hamiltonian of these systems. Cubic magnetic sublattices of size L3, with L = 20, 24 and 28, were investigated in this study to compute the magnetization and the magnetic susceptibility as a function of temperature (T) at various applied fields. In order to calculate the variation of the magnetic entropy versus the applied magnetic field, we have examined an isothermal process by considering a term of magneto-crystalline anisotropy. In order to validate the results, many parameters were calculated. The results obtained are in good agreement with the experimental ones. The high relative cooling power values of our compounds leads to promising material for magnetic refrigeration technology. This material could be considered as a good candidate for applications requiring high values of TC.

Room-temperature magnetoresistive and magnetocaloric effect in La1−xBaxMnO3 compounds: Role of Griffiths phase with ferromagnetic metal cluster above Curie temperature

The evolution of the Griffiths phase (GP) with a ferromagnetic metal (FMM) cluster above the Curie temperature (TC) and its effect on the magnetic properties, electrical transport, magnetoresistance (MR), and magnetocaloric effect (MCE) is studied comprehensively, using bulk compounds of La1−xBaxMnO3 (0.15 ≤ x ≤ 0.25) with different lattice distortions but with the same structural symmetry and space group. These La1−xBaxMnO3 samples show ferromagnetic transition at TC increasing from 229 K for x = 0.15–300 K for x = 0.25, in addition to the presence of GP with FMM clusters in the paramagnetic (PM) region, which have been confirmed by the combination of magnetization (susceptibility) measurements, the GP theory, and electron paramagnetic resonance technology. With increasing the Ba2+ ion doping, GP temperature (TG) and TC of La1−xBaxMnO3 are increased, and the GP regime is strengthened. The GP ratio in the PM region reached 27.7% for the sample with x = 0.20. The resistivity decreases and the FMM phase increases with increasing x from 0.15 to 0.25, which can be explained by the decrease in the bandgap (Eg) and the enhancement of the double-exchange effect. Remarkably, large room-temperature MR (∼44.7%) can be observed in the sample with x = 0.25 under 60 kOe, which is related to the presence of the GP regime. Furthermore, the MCE is also affected by the GP regime, and it is deduced that the magnetic transition is of second order. The value of magnetic entropy change (|ΔSM|) reaches 3.04 J/kg K near room temperature for the sample with x = 0.25 under 50 kOe. This value is associated with a relative cooling power (RCP) of 248.1 J/kg. For the sample with x = 0.15, the value of RCP reaches 307.6 J/kg under 50 kOe. The discovery of the MR and MCE near room temperature is of great significance from the practical application of perovskite manganites in magnetic sensors and magnetic refrigerants.