Edge-Defined Film-Fed Growth of Incongruent-Melting Ce, Sc, Ca:EuIG Crystal with High Magneto-Optical Performance

Magneto-optical crystals play a decisive role in the performance of optical isolators in fields such as optical fiber communication and laser sensing. However, conventional materials are often limited by inadequate temperature stability and high optical loss. To overcome these challenges, a novel Ce/Sc-codoped europium iron garnet crystal (CexEu3–x–zCazScyFe5–yO12) was designed and successfully grown using an optimized edge-defined film-fed growth method. This work systematically elucidates the synergistic effect of codoping on the crystal structure and magneto-optical properties. Experiments show that Sc3+ doping effectively reduces the strength of the superexchange interaction by changing the bond length (the Fe23+–O2– bond shortens by 0.03 Å) and bond angle (the Fe13+–O2––Fe23+ angle decreases by 2.8°) of the [FeO6] octahedron, lowering the Curie temperature of the Ce0.30Eu2.57Ca0.13Sc0.79Fe4.21O12 crystal to 95 °C. The introduction of Ce3+ significantly increases the saturation specific Faraday rotation angle at a wavelength of 1550 nm to –637.9 deg cm–1. This value is 3.5 times that of YIG and corresponds to 60% of the value for commercial Bi:RIG crystals. This work breaks through the limitations of traditional magneto-optical materials with high temperature sensitivity and insufficient optical performance, providing a material basis for the development of a new generation of optical isolators with a wide temperature range and low loss.