Multiple-phase evolution and electrical transport of Sr 4- x Y x Co 4 O 12- δ ( x = 0-1.0): an ordered phase transition process

• Published in: Dalton transactions : an international journal of inorganic chemistry 2023-04, Vol.52 (14), p.4398-4406
• Main Authors: Song, Hongyuan, Liu, Bin, Zeng, Jinhua, Huo, Guangpeng, Chen, Liangwei, Wang, Jianlu, Yu, Lan
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/D3DT00294B

The transition metal oxide (TMO) SrCoO family with rich structural diversity has been widely studied in the phase transition and energy application fields. We report the multiple-phase structure evolution, phase transitions during sintering, and electrical transport of A-site doped Sr Y Co O ( = 0-1.0) ceramics. Sr Co O ( = 0) adopts a hexagonal structure (H), Sr Y Co O ( = 0.2-0.4) ceramics adopts a cubic perovskite (CP) structure, and Sr Y Co O ( = 0.8-1.0) ceramics adopts an ordered-tetragonal (OT) structure; moreover, their phase transitions during the sintering processing of samples are systematically investigated. Combining the thermal analysis and X-ray diffraction results, the exothermic peak and weight gain of Sr YCo O ( = 1.0, T) at 1042 °C are considered to correspond to an ordered phase transition (T → OT) occurring. Finally, a systematic phase schema of the Sr Y Co O ( = 0-1.0) state dependence on the Y content and sintering temperature is obtained. The high-energy Y-O bond stabilizes the high-temperature CP structure ( = 0.2-0.4) and induces a structural evolution from the CP to OT structure ( = 0.8-1.0). In addition, all Sr Y Co O ( = 0-1.0) ceramics show semiconductive electrical transport behavior. Sr Co O (H) with a one-dimensional chain structure has the highest resistivity, while Sr Y Co O (CP) with a three-dimensional corner-sharing structure exhibits the lowest resistivity, and Sr Y Co O ( = 0.2-1.0) ceramics show an increasing tendency in resistivity due to the hole carrier Co converting to Co . We studied multiple-phase evolution and ordered phase transition in Sr Y Co O ( = 0-1.0) ceramics through Y-O bonding.