Since Warburg's discovery of the magneto-caloric effect (MCE) in 1881, researchers have invested decades exploring its applications in the realm of magnetic cooling not only at room temperature but also at cryogenic temperatures. TmGa has emerged as a focus due to its notably high MCE performance. However, discrepancies have surfaced between the findings on single-crystalline TmGa reported by Gao et al. in 2013 and subsequent reports on polycrystalline TmGa. These disparities present significant challenges for ongoing TmGa research. To address these inconsistencies, this study prepares TmGa in a textured polycrystalline form. Magnetic measurements along both parallel and perpendicular to the -axis reveal pronounced magnetic anisotropy between the two directions. Notably, a distinct and complex anisotropic field-dependence in magnetic interaction and corresponding transitions are observed. Furthermore, magnetic entropy changes for both and , along with the corresponding anisotropic entropy change , are computed based on Maxwell’s relations. This investigation discloses maximum values of , reaching 17.2 J/kg K at = 16.5 K and 24.3 J/kg K at = 11.5 K for fields of 20 and 50 kOe, respectively, which are close to the largest value to date. These findings provide insights into fundamental magnetic properties and their potential applications for rotational magneto-caloric effects.

中文翻译：

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织构 TmGa 中的磁各向异性和相关熵变化

自 1881 年 Warburg 发现磁热效应 (MCE) 以来，研究人员投入了数十年的时间探索其在磁冷却领域的应用，不仅在室温下，而且在低温下。 TmGa 因其极高的 MCE 性能而成为人们关注的焦点。然而，Gao 等人报道的单晶 TmGa 发现之间存在差异。 2013年以及随后关于多晶TmGa的报道。这些差异给正在进行的 TmGa 研究带来了重大挑战。为了解决这些不一致问题，本研究制备了织构多晶形式的 TmGa。沿着平行和垂直于 轴的磁测量揭示了两个方向之间明显的磁各向异性。值得注意的是，观察到磁相互作用和相应转变中独特且复杂的各向异性场依赖性。此外， 和 的磁熵变化以及相应的各向异性熵变化 是根据麦克斯韦关系式计算的。这项研究揭示了 的最大值，在 20 kOe 和 50 kOe 的磁场下分别达到 17.2 J/kg K（在 = 16.5 K 时）和 24.3 J/kg K（在 = 11.5 K 时），这接近迄今为止的最大值。这些发现提供了对基本磁特性及其在旋转磁热效应中的潜在应用的见解。