Cho Yujin, Kang Seohui, Nahm Yeon Woo, Mohamed Ahmed Yousef, Kim Yejin, Cho Deok-Yong, Cho Suyeon
Division of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, ELTEC College of Engineering, Ewha Womans University, Seoul 03760, Republic of Korea.
IPIT and Department of Physics, Jeonbuk National University, Jeonju 54896, Republic of Korea.
ACS Omega. 2022 Jul 15;7(29):25078-25086. doi: 10.1021/acsomega.2c01334. eCollection 2022 Jul 26.
We synthesized a series of slightly erbium-substituted yttrium iron garnets (Er:YIG), Y Er FeO at different Er concentrations ( = 0, 0.01, 0.05, 0.10, and 0.20) using a solid-state reaction and investigated their structural, magnetic, and optical properties as a function of Er concentration. The volume of the unit cell slightly increased with Er concentration and Er atoms predominately replaced Y atoms in the dodecahedrons of YIG. The optical properties exhibited certain decreases in reflectance in the 1500-1600 nm wavelength range due to the presence of Er. Despite the many unpaired 4f electrons in Er, the total magnetic moments of Er:YIG showed similar trends with temperatures and magnetic fields above 30 K. An X-ray magnetic circular dichroism study confirmed the robust Fe 3d magnetic moments. However, the magnetic moments suddenly decreased to below 30 K with Er substitution, and the residual magnetism ( ) and coercive field ( ) in the magnetic hysteresis loops decreased to below 30 K with Er substitution. This implies that Er substitution in YIG has a negligible effect on magnetic properties over a wide temperature range except below 30 K where the Er 4f spins are coupled antiparallel to the majority Fe 3d spins. Our studies demonstrated that above 30 K the magnetic properties of YIG are retained even with Er substitution, which is evidence that the Er doping scheme is applicable for YIG-based magneto-optical devices in the mid-infrared regime.
我们采用固态反应合成了一系列不同铒（Er）浓度（= 0、0.01、0.05、0.10和0.20）的轻度铒取代钇铁石榴石（Er:YIG），即Y₃₋ₓErₓFe₅O₁₂，并研究了它们的结构、磁性和光学性质随Er浓度的变化。随着Er浓度的增加，晶胞体积略有增加，且Er原子主要取代了YIG十二面体中的Y原子。由于Er的存在，光学性质在1500 - 1600 nm波长范围内的反射率出现了一定程度的下降。尽管Er中有许多未成对的4f电子，但在30 K以上，Er:YIG的总磁矩随温度和磁场呈现出相似的趋势。X射线磁圆二色性研究证实了Fe 3d磁矩的稳定性。然而，随着Er取代，磁矩在30 K以下突然下降，磁滞回线中的剩余磁性（Mr）和矫顽场（Hc）也随着Er取代在30 K以下下降。这意味着在YIG中进行Er取代，除了在30 K以下Er 4f自旋与多数Fe 3d自旋反平行耦合的情况外，在很宽的温度范围内对磁性的影响可以忽略不计。我们的研究表明，在30 K以上，即使进行了Er取代，YIG的磁性仍然得以保留，这证明了Er掺杂方案适用于中红外波段基于YIG的磁光器件。
