Direct observation of multivalent states and 4 f → 3d charge transfer in Ce-doped yttrium iron garnet thin films
Direct observation of multivalent states and 4 f → 3d charge transfer in Ce-doped yttrium iron garnet thin films
复制标题
DOI：
10.1103/physrevb.96.014433
复制
发表时间：
2017-07
期刊：
影响因子：
--
通讯作者：
H. B. Vasili;B. Casals;R. Cichelero;J. Geshev;P. Gargiani;M. Valvidares;J. Herrero‐Martín;E. Pellegrin;J. Fontcuberta;G. Herranz
中科院分区：
文献类型：
--
作者：
H. B. Vasili;B. Casals;R. Cichelero;J. Geshev;P. Gargiani;M. Valvidares;J. Herrero‐Martín;E. Pellegrin;J. Fontcuberta;G. Herranz
由于其巨大的磁光响应，稀土掺杂钇铁石榴石 ${\mathrm{Y}}_{3}\mathrm{F}{\mathrm{e}}_{5}{\mathrm{O}}_{12}$ (YIG) 因其在 光子学和磁子学。在这里，我们考虑 Ce 掺杂 YIG (Ce-YIG) 薄膜的情况，其中替代的 $\mathrm{C}{\mathrm{e}}^{3+}$ 离子由于其 $4{f}^{1}$ 基态而具有磁性。为了阐明Ce取代对YIG磁化强度的影响，我们对Ce-YIG薄膜进行了软X射线光谱测量。特别是，我们利用 X 射线磁圆二色性的元素特异性来提取与 Ce 和 Fe 离子相关的各个磁化曲线。我们的结果表明，Ce 掺杂触发了从 Ce 到 YIG 结构中 Fe 四面体位点的选择性电荷转移。这反过来又会导致母体化合物的电子和磁性破坏，减少 Ce 和 Fe 磁矩之间的交换耦合，并导致非典型的磁性行为。我们的工作与理解稀土掺杂 YIG 中的磁性相关，并最终可能能够定量评估稀土掺入 YIG 的磁光特性。
Due to their large magneto-optic responses, rare-earth-doped yttrium iron garnets, ${\mathrm{Y}}_{3}\mathrm{F}{\mathrm{e}}_{5}{\mathrm{O}}_{12}$ (YIG), are highly regarded for their potential in photonics and magnonics. Here, we consider the case of Ce-doped YIG (Ce-YIG) thin films, in which substitutional $\mathrm{C}{\mathrm{e}}^{3+}$ ions are magnetic because of their $4{f}^{1}$ ground state. In order to elucidate the impact of Ce substitution on the magnetization of YIG, we have carried out soft x-ray spectroscopy measurements on Ce-YIG films. In particular, we have used the element specificity of x-ray magnetic circular dichroism to extract the individual magnetization curves linked to Ce and Fe ions. Our results show that Ce doping triggers a selective charge transfer from Ce to the Fe tetrahedral sites in the YIG structure. This, in turn, causes a disruption of the electronic and magnetic properties of the parent compound, reducing the exchange coupling between the Ce and Fe magnetic moments and causing atypical magnetic behavior. Our work is relevant for understanding magnetism in rare-earth-doped YIG and, eventually, may enable a quantitative evaluation of the magneto-optical properties of rare-earth incorporation into YIG.