标题： 欧锌磁极子在EuZn$_2$P$_2$中的形成 显示英文标题

标题： Magnetic polaron formation in EuZn$_2$P$_2$

摘要： 巨磁电阻（CMR）已在许多Eu$^{2+}$基材料中被观察到；然而，其起源尚未完全明确。 在这里，我们通过单晶X射线衍射、透射电子显微镜、电输运、磁化、膨胀计和电子自旋共振测量，并结合密度泛函理论计算，研究了反铁磁绝缘体EuZn$_2$P$_2$。 我们的电导率数据揭示了一个大的负磁阻，$MR = [R(H)-R(0)]/R(0)$，在接近反铁磁有序温度$T_N=23\ \text{K}$的9~T时达到$MR = -99.7\%$。 膨胀计测量显示伴随着磁场引起的晶格应变。 此外，Eu$^{2+}$电子自旋共振显示Eu$^{2+}$与传导电子之间存在强铁磁交换相互作用。我们的实验结果在EuZn$_2$P$_2$中与磁极子情景一致，并表明磁极子形成是Eu$^{2+}$基化合物中CMR的主要解释。 显示英文摘要

摘要： Colossal magnetoresistance (CMR) has been observed across many Eu$^{2+}$-based materials; however, its origin is not completely understood. Here we investigate the antiferromagnetic insulator EuZn$_2$P$_2$ through single crystal x-ray diffraction, transmission electron microscopy, electrical transport, magnetization, dilatometry, and electron spin resonance measurements complemented by density functional theory calculations. Our electrical resistivity data reveal a large negative magnetoresistance, $MR = [R(H)-R(0)]/R(0)$, that reaches $MR = -99.7\%$ at 9~T near the antiferromagnetic ordering temperature $T_N=23\ \text{K}$. Dilatometry measurements show an accompanying field-induced lattice strain. Additionally, Eu$^{2+}$ electron spin resonance reveals a strong ferromagnetic exchange interaction between Eu$^{2+}$ and conduction electrons. Our experimental results in EuZn$_2$P$_2$ are consistent with a magnetic polaron scenario and suggest magnetic polaron formation as a prevailing explanation of CMR in Eu$^{2+}$-based compounds.