Synthesis, structure, magnetic and photoelectric properties of Ln 3 M 0.5 M′Se 7 (Ln = La, Ce, Sm; M = Fe, Mn; M′ = Si, Ge) and La 3 MnGaSe 7

• Published in: RSC advances 2015, Vol.5 (65), p.52629-52635
• Main Authors: He, Jianqiao, Wang, Zhe, Zhang, Xian, Cheng, Ye, Gong, Yu, Lai, Xiaofang, Zheng, Chong, Lin, Jianhua, Huang, Fuqiang
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C5RA05629B

Six new isostructural compounds, with the formulas La 3 Fe 0.5 GeSe 7 , La 3 MnGaSe 7 , Ce 3 Fe 0.5 SiSe 7 , Ce 3 Mn 0.5 SiSe 7 , Sm 3 Fe 0.5 SiSe 7 and Sm 3 Mn 0.5 GeSe 7 , have been successfully synthesized via a molten salt method. Their structures are determined by single crystal X-ray diffraction and they crystallize in the Ce 6 Al 3.33 S 14 structure type (space group: P 6 3 , Pearson symbol: hP 24). Pure phases of the Ce 3 Fe 0.5 SiSe 7 , Ce 3 Mn 0.5 SiSe 7 , Sm 3 Fe 0.5 SiSe 7 and Sm 3 Mn 0.5 GeSe 7 compounds were obtained by solid state reaction and were characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), ultraviolet-visible-infrared (UV-vis-IR) absorbance spectroscopy, and magnetization measurements. The Ce 3 Fe 0.5 SiSe 7 and Ce 3 Mn 0.5 SiSe 7 compounds show paramagnetic domination accompanied by antiferromagnetic contributions, while the Sm 3 Mn 0.5 GeSe 7 and Sm 3 Fe 0.5 SiSe 7 compounds show anti-ferromagnetic phase transitions with Néel temperatures of 13 K and 24 K, respectively. Optical measurements reveal that all of the four compounds can absorb most of visible light. These four compounds also show photoelectric properties with the photocurrent densities of 81, 1.3, 1.8 and 0.8 μA cm −2 , respectively.