Role of Ca2+ doping on the structure, magnetic, and magnetocaloric properties of La0.75Gd0.05Sr0.2−xCaxMnO3 (x = 0, 0.05, 0.075, and 0.10) perovskite manganites

• Published in: Journal of materials science. Materials in electronics 2023-04, Vol.34 (10), p.911, Article 911
• Main Authors: Zhang, Weijian, He, Bangrong, Zou, Zhengguang, Xie, Zhuojia, Jiang, Xinyu, Mao, Zheng, Xu, Changji, Feng, Min
• Format: Article
• Language: English
• Subjects: Calcium ions; Characterization and Evaluation of Materials; Chemistry and Materials Science; Curie temperature; Doping; Ferromagnetism; Magnetic fields; Magnetic properties; Manganites; Materials Science; Morphology; Optical and Electronic Materials; Perovskites; Phase transitions; Room temperature; Scanning electron microscopy; Sol-gel processes
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-023-10311-2

In this paper, La 0.75 Gd 0.05 Sr 0.2- x Ca x MnO 3 perovskite manganites were synthesized by the sol-gel method, and the effects of Ca 2+ ( x  = 0, 0.05, 0.075, and 0.10) doping on the structural, magnetic, and magnetocaloric properties of the samples were investigated. All the samples exhibited a rhombic structure with R-3c space group symmetry; however, the incorporation of calcium ions leads to an increase in the Mn–O bond length and a reduction in the Mn-O-Mn bond angle, which weakens the double exchange effect and lowers the Curie temperature of the sample. For all the samples, it was demonstrated that the types of ferromagnetic–paramagnetic were second-order magnetic phase transitions. The magnetic entropy changes of the samples were also found to be positively correlated with the amount of Ca 2+ doping, indicating that this group of samples is a suitable candidate for room-temperature magnetic refrigeration materials.