(Sc,Ti)Fe₂ Laves phases present a relatively unique case of first-order ferro-ferromagnetic transition originating from an instability of the Fe moment. In addition to large magnetoelastic effects making them potential negative thermal expansion materials, here, we show that Sc_0.28Ti_0.72Fe₂ and related alloys also present sizable magnetocaloric and magnetoresistance effects. Both effects are found substantially larger at the ferro-ferromagnetic transition (T_t1) than near the Curie temperature T_C, yet they remain limited in comparison to other classes of giant magnetocaloric materials. We suggest a strategy to improve these properties by bringing the transition at T_t1 close to T_C, and test its possible realization by Co or Mn for Fe substitutions. The structural and magnetic phase diagrams of Sc_0.28Ti_0.72Fe_2−xT_x alloys with T = Mn or Co are explored. Substitutions for Fe by adjacent Mn or Co elements give rise to a breakdown of the long-range ferromagnetic order, as well as a swift disappearance of finite moment magnetism.

中文翻译：

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T = Mn或Co的磁热效应，Sc0.28Ti0.72Fe2的磁阻和Sc0.28Ti0.72Fe2-xTx合金的相图

（Sc，Ti）Fe ₂ Laves相呈现出一个相对独特的情况，即由Fe矩的不稳定性引起的一阶铁-铁磁跃迁。除了大的磁弹性效应使它们成为潜在的负热膨胀材料外，在这里，我们还表明Sc _0.28 Ti _0.72 Fe ₂和相关合金还表现出相当大的磁热效应和磁阻效应。发现这两种效应在铁磁-铁磁跃迁（T _t1）处都比居里温度T _C附近大得多。但是，与其他类别的巨型磁热材料相比，它们仍然受到限制。我们提出了一种通过使T _t1处的跃迁接近T _C来改善这些性能的策略，并测试通过Co或Mn替代Fe可能实现的性能。探索了T = Mn或Co的Sc _0.28 Ti _0.72 Fe _{2− x} T _x合金的结构和磁相图。相邻的Mn或Co元素取代Fe会导致长距离铁磁有序分解，并且有限矩磁性迅速消失。