论文标题
反铁磁性欧盟中的磁极探针的微观探针
Microscopic probe of magnetic polarons in antiferromagnetic Eu$_{5}$In$_{2}$Sb$_{6}$
论文作者
论文摘要
巨大的磁化（CMR）以相互缠绕的自旋和电荷自由度出现，形式的铁磁簇也称为捕获的磁极。结果，在抗磁磁材料中很少观察到CMR。在这里，我们使用电子自旋共振（ESR）揭示了抗铁磁性欧盟中磁极的形成的微观证据，$ _ {5} $ in $ _ {2} $ sb $ _ {6} $。首先，我们观察到Eu $^{2+} $ ESR线宽的降低，这是与抗铁磁磁场一致的应用磁场的函数。此外，欧盟$^{2+} $ lineshape在t'〜200 k以下显着变化，这种温度比例与CMR的发作相吻合。这两种效应的组合提供了有力的证据，表明磁极在T'以下的大小生长，并开始影响系统的宏观特性。
Colossal magnetoresistance (CMR) emerges from intertwined spin and charge degrees of freedom in the form of ferromagnetic clusters also known as trapped magnetic polarons. As a result, CMR is rarely observed in antiferromagnetic materials. Here we use electron spin resonance (ESR) to reveal microscopic evidence for the formation of magnetic polarons in antiferromagnetic Eu$_{5}$In$_{2}$Sb$_{6}$. First, we observe a reduction of the Eu$^{2+}$ ESR linewidth as a function of the applied magnetic field consistent with ferromagnetic clusters that are antiferromagnetically coupled. Additionally, the Eu$^{2+}$ lineshape changes markedly below T' ~ 200 K, a temperature scale that coincides with the onset of CMR. The combination of these two effects provide strong evidence that magnetic polarons grow in size below T' and start influencing the macroscopic properties of the system.
