论文标题
二价化合物中兰烷的局部力矩的一阶铁磁过渡：流动的电子反馈机制和费米的表面拓扑变化
First-order ferromagnetic transitions of lanthanide local moments in divalent compounds: An itinerant electron positive feedback mechanism and Fermi surface topological change
论文作者
论文摘要
在不连续的（一阶）磁相横向周围，材料对小场的应用的强量响应得到了广泛研究，以开发固态制冷。通常，强烈的磁结构耦合可以驱动此类过渡，而随之而来的磁滞会大大降低冷却性能。在这种情况下，我们描述了一种纯粹的电子机制，该机制在二价灯笼化合物中试行了一阶顺磁性磁性过渡，并解释了最近在化合物中欧盟$ _2 $中发现的巨型非迟发磁性效应。巡回价电子的磁性与局部$ F $ -Electron矩的铁磁顺序之间存在积极的反馈，这似乎是对费米表面的拓扑变化。该电子机制的起源直接源于欧盟的差距，这解释了GD $ _2 $ IN中没有类似的不连续过渡。
Around discontinuous (first-order) magnetic phase transitions the strong caloric response of materials to the application of small fields is widely studied for the development of solid-state refrigeration. Typically strong magnetostructural coupling drives such transitions and the attendant substantial hysteresis dramatically reduces the cooling performance. In this context we describe a purely electronic mechanism which pilots a first-order paramagnetic-ferromagnetic transition in divalent lanthanide compounds and which explains the giant non-hysteretic magnetocaloric effect recently discovered in a Eu$_2$In compound. There is positive feedback between the magnetism of itinerant valence electrons and the ferromagnetic ordering of local $f$-electron moments, which appears as a topological change to the Fermi surface. The origin of this electronic mechanism stems directly from Eu's divalency, which explains the absence of a similar discontinuous transition in Gd$_2$In.
