Hydrothermal Synthesis and Optical Properties of Magneto-Optical Na₃FeF₆:Tb³⁺ Octahedral Particles

Sodium iron hexafluoride (Na₃FeF₆), as a colorless iron fluoride, is expected to be an ideal host for rare earth ions to realize magneto-optical bi-functionality. Herein, monodispersed terbium ions (Tb³⁺) doped Na₃FeF₆ particles are successfully synthesized by a facile one-pot hydrothermal process. X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM) reveal that the Tb³⁺ doped Na₃FeF₆ micro-particles with regular octahedral shape can be assigned to a monoclinic crystal structure (space group P21/c). Under ultraviolet light excitation, the Na₃FeF₆:Tb³⁺ octahedral particles given orange-red light emission originated from the ⁵D₄→⁷F_J transitions of the Tb³⁺ ions. In addition, the magnetism measurement indicates that Na₃FeF₆:Tb³⁺ octahedral particles are paramagnetic with high magnetization at room temperature. Therefore, the Na₃FeF₆:Tb³⁺ powders may find potential applications in the biomedical field as magnetic-optical bi-functional materials.