We report magnetic and magnetocaloric properties of Sm0.6-xLaxSr0.4MnO3 (x = 0-0.6). A rapid increase around TC and an anomalous peak at a temperature T*<<TC occur in magnetization which lead to normal and inverse magnetocaloric effects (MCE), respectively. While TC increases with increasing x (TC=118 K for x=0 and TC=363 K for x=0.6), T* increases from 30 K (x=0) to 120 K (x=0.4) and then decreases to 105 K (x=0.5). The \DeltaSm reaches +1.07 Jkg-1K-1 at 10 K and -4 Jkg-1K-1 around TC in x=0.4 for ΔH=5T. The inverse MCE is attributed to antiferromagnetic coupling between Sm-4f and Mn-3d magnetic moments.
We have employed Gd55Co30NixAl15-x (x = 10, 5 and 0) amorphous microwires as a model system to unravel the impact of multiple magnetic interactions on the magnetism and the magnetocaloric behavior in Gd-alloy microwire systems. Our study shows that in addition to the RKKY ferromagnetic (FM) interaction (Gd-Gd), antiferromagnetic (AFM) interactions (Gd-Co, Gd-Ni) coexist and contribute to the magnetic and magnetocaloric response of the system. The dilution effect of Al element on the FM Gd-Gd interaction is responsible for the decrease of the Curie temperature (TC), whereas the increase of the …
Magnetic ground state, critical analysis of magnetization, and large magnetocaloric effect in the ferromagnetically coupled kagome lattice YCa$_3$(MnO)$_3$(BO$_3$)$_4$
We present a thorough study on the magnetoanisotropic properties and magnetocaloric effect in the layered ferromagnetic Cr$_4$Te$_5$ single crystals by performing the critical behaviour analysis of magnetization isotherms. The critical exponents $β$=0.485(3), $γ$=1.202(5), and $δ$=3.52(3) with a Curie temperature of $T_C \approx 340.73(4)$ K are determined by the modified Arrott plots. We observe a large magnetocrystalline anisotropy K$_u$=330 kJ/$m^3$ at 3 K which gradually decreases with increasing temperature. Maximum entropy change -$ΔS_{M}^{max}$ and the relative cooling power (RCP) are f…
We report the effect of exchange frustration on the magnetocaloric properties of GdCrTiO$_5$ compound. Due to the highly exchange-frustrated nature of magnetic interaction, in GdCrTiO$_5$, the long-range antiferromagnetic ordering occurs at much lower temperature $T_N$=0.9 K and the magnetic cooling power enhances dramatically relative to that observed in several geometrically frustrated systems. Below 5 K, isothermal magnetic entropy change (-$ΔS_{\rm m}$) is found to be 36 J kg$^{-1}$ K$^{-1}$, for a field change ($ΔH$) of 7 T. Further, -$ΔS_{\rm m}$ does not decrease from its maximum value …
The rotating magnetocaloric effect (RMCE) is a recent interest in magnetic refrigeration technique in which the cooling effect is attained by rotating the anisotropic magnetocaloric material from one orientation to the other in a fixed magnetic field. In this work, we report the anisotropic magnetocaloric properties of single crystals of the ferromagnetic Weyl semimetal Co$_{3}$Sn$_{2}$S$_{2}$ for magnetic field $H\parallel c$ axis and $H\parallel ab$ plane. We observed a significant (factor of $2$) difference between the magnetocaloric effect measured in both orientations. The rotating magnet…
We report the structural, magnetic properties, and magnetocaloric effect of a new polycrystalline compound of $\mathrm{Tb_2Rh_3Ge}$. This present compound crystallizes with $\mathrm{Mg_2Ni_3Si}$-type of rhombohedral Laves phases (space group $R\overline{3}m$, hR18). The magnetic properties and magnetocaloric effect of the $\mathrm{Tb_2Rh_3Ge}$ is explored through dc-magnetization measurements. Temperature dependence of magnetization revealed that the compound exhibits ferromagnetic behavior with $T_C$$=$56 K. The field dependence of magnetization indicates that $\mathrm{Tb_2Rh_3Ge}$ is a soft …
Indirect exchange coupling in magnetic multilayers, also known as the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, is known to be highly effective in controlling the interlayer alignment of the magnetization. This coupling is typically fixed at the stage of the multilayer fabrication and does not allow ex-situ control needed for device applications. It is highly desirable, in addition to the orientational control, to also control the magnitude of the intralayer magnetization, ideally switch it on/off by switching the relevant RKKY coupling. Here we demonstrate a magnetic multilayer materi…
We present the results of a comparative analysis of the magnetocaloric effect (MCE) in Pr0.7Sr0.2Ca0.1MnO3, through direct and indirect measurements, using experimentally measured magnetization, specific heat, magnetostriction, resistivity, thermal diffusivity and thermal conductivity parameters. We have demonstrated that the change in each parameter in response to a magnetic field near the ferromagnetic-paramagnetic phase transition temperature of the material correlates with the change in magnetic entropy. These findings allow us to interrelate these parameters and provide an alternative, ef…
Processing magnetocaloric materials into magnetic refrigerant particles is an essential issue in developing high-performance magnetic refrigerators. Here, we succeed in stably producing magnetocaloric particles of the promising material HoAl2 by a newly devised method based on electrode induction melting gas atomization process. The particle size range is on the order of submillimeter, which is suitable for practical refrigeration systems. The resulting particles with less contamination have good morphological, magnetic, and magnetocaloric properties: (i) almost spherical shapes with few inter…
Oscillating magnetocaloric effect of a 2D non-relativistic diamagnetic material
在磁性材料中，具有铁磁特性的磁性材料是迄今为止在磁热效应应用方面研究最多的材料。近年来，抗磁性材料受到了前所未有的关注，并发现了类似于de Haas-van Alphen效应的振荡行为，本文详细描述了二维非相对论材料的磁热性质（例如，金薄膜），其中振荡取决于互易磁场$1/B$，比较了几种情况下每个电子的磁熵变，发现石墨烯的磁熵变为$\approx10^{-1}$ k $_{\text{B}}$（@109.3 K），二维金的磁熵变为$\approx10^{-5}$ k $_{\text{B}}$（@0.7 K），三维金的磁熵变为$\approx 10^{-7}$ k $_{\text{B}}$（@0.7 K）.
In this paper, a theoretical journey from electronic to magneto-caloric effect has been shown through the magnetic properties of aluminium induced yttrium chromate. The ground state electronic band structure and density of states have been studied using first principle calculations under GGA+U schemes. From the energy minimization, the ferromagnetic structure is more stable than the antiferromagnetic one. The interaction constant as well as the magnetic moment, have been determined from mean-field theory and DFT, respectively. The Monte-Carlo simulation under Metropolis algorithm has been empl…
In this paper, we mainly focus on the magnetic and magnetocaloric features of La2-xDyxNiMnO6 double perovskites. Their magnetocaloric properties are investigated in terms of both entropy and adiabatic temperature changes. In contrast to early works, it was found that the Dy2NiMnO6 compound unveils dominant antiferromagnetic interactions under very low magnetic fields. The ordering of its Dy3+ magnetic moments is associated with a giant magnetocaloric effect at very low temperatures, while the established ferromagnetic Ni-O-Mn super-exchange interactions close to 100 K give rise to a moderate m…
Layered van der Waals ferromagnets are promising candidates for designing new spintronic devices. Here we investigated the critical properties and magnetocaloric effect connected with ferromagnetic transition in layered van der Waals VI$_3$ single crystals. The critical exponents $β= 0.244(5)$ with a critical temperature $T_c = 50.10(2)$ K and $γ= 1.028(12)$ with $T_c = 49.97(5)$ K are obtained from the modified Arrott plot, whereas $δ= 5.24(2)$ is obtained from a critical isotherm analysis at $T_c = 50$ K. The magnetic entropy change $-ΔS_M(T,H)$ features a maximum at $T_c$, i.e., $-ΔS_M^{max…
Barocaloric and Magnetocaloric Effects in Fe49Rh51
本文报道了在外加静水压和磁场作用下Fe $_{49}$ Rh $_{51}$的反铁磁（AFM）-铁磁（FM）相变的量热研究。结果表明，存在一个巨大的压热效应，在这种合金，一个新的功能特性，增加了磁热和弹性热效应，以前报道的这种合金。所有的热效应都源于AFM/FM转变，其中包括体积、磁化强度和熵的变化。转变温度对流体静压和磁场的强烈敏感性赋予该合金优异的压热和磁热强度值（$|ΔS|$/$Δp$ $\sim$ 12 J kg $^{-1}$ K $^{-1}$ kbar $^{-1}$ and $|ΔS|$/$μ_0ΔH$ $\sim$ 12 J kg $^{-1}$ K $^{-1}$ T $^{-1}$）。已经发现压热和磁热效应两者在压力和磁场循环时是可再现的。这种良好的再现性和大的热强度使得Fe-Rh合金在弱外部刺激下特别适合固态冷却技术。
We report on the structural, magnetic, and magnetocaloric properties of polycrystalline (La0.5Pr0.5)0.6Ba0.4MnO3 (LPBMO), which was fabricated by a conventional solid-state reaction method. LPBMO undergoes a second-order paramagnetic to ferromagnetic (PM-FM) phase transition around a Curie temperature TC ~ 277 K. The maximum magnetic entropy change is ~ 3.22 J kg-1 K-1 for a magnetic field change of 5 T. Based on the modified-Arrott plot and the iterative Kouvel Fisher methods, a set of critical exponents (beta = 0.514, gamma = 1.164, and delta = 3.265) are determined. These values are close t…
We report anisotropic magnetocaloric effect and magnetic critical behavior in van der Waals crystal CrCl$_3$. The maximum magnetic entropy change $-ΔS_M^{max} \sim 14.6$ J kg$^{-1}$ K$^{-1}$ and the relative cooling power $RCP \sim 340.3$ J kg$^{-1}$ near $T_c$ with a magnetic field change of 5 T are much larger when compared to CrI$_{3}$ or CrBr$_{3}$. The rescaled $ΔS_M(T,H)$ curves collapse onto a universal curve, confirming the second order ferromagnetic transition. Further critical behavior analysis around $T_c$ presents a set of critical exponents $β$ = 0.28(1) with $T_c$ = 19.4(2) K, $γ…
