Electrical and magnetic properties of double perovskite Y2-xCaxCoMnO6 (x = 0.1, 0.2, 0.5)

• Published in: Journal of materials science. Materials in electronics 2024-09, Vol.35 (25), p.1670, Article 1670
• Main Authors: Kumar, Dheeraj, Alam, Mohd, Singh, Prajyoti, Dixit, Srishti, Ghosh, A. K., Chatterjee, Sandip
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Calcium ions; Characterization and Evaluation of Materials; Chemistry and Materials Science; Cobalt; Crystal structure; Electrical conduction; Electrons; Energy gap; Ferromagnetism; Hopping conduction; Low temperature; Magnetic permeability; Magnetic properties; Magnetization; Materials Science; Optical and Electronic Materials; Perovskite structure; Perovskites; Photoelectric emission; Room temperature; Temperature; Temperature dependence; Transport properties
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-024-13399-2

The crystal structure, electronic, magnetic, and transport properties of the hole substituted (Ca 2+ ) and partially B-site disordered double perovskite Y 2-x Ca x CoMnO 6 system are studied. At room temperature, the samples demonstrated a monoclinic perovskite structure with a space group P2 1 /n which was confirmed by Rietveld refinement of X-ray diffraction data. Ultra-violet visible analysis of these samples shows a direct band gap including gap energy near about 1.50 eV. X-ray photoemission spectroscopy measurement shows that component Co and Mn ions exist in a mixed state (Co 3+ , Co 2+ , Mn 3+ , and Mn 4+ ). All samples exhibit semiconducting/insulating, and electrical conduction can be explained by Mott’s 3-D variable range hopping and small polaron hopping fitting. The magnetization numerical value decreases observed with increases in Ca concentration appears to be caused by increases in antiferromagnetic (AFM) phases. The double perovskite Y 1.9 Ca 0.1 CoMnO 6 and Y 1.8 Ca 0.2 CoMnO 6 show ferromagnetic transition at transition temperatures T c  ~ 70 K and T c  ~ 68 K, respectively. The analysis of the samples’ zero fields cooled DC magnetic susceptibility as a function of temperature reveals Griffiths-like singularity features that arise as the concentration of Ca increases in the parent system. The Griffith-like phase exists in the sample Y-site with Ca-substitution is independent of the structural disorder caused by the John–Teller active Mn 3+ ions in sample Y 1.5 Ca 0.5 CoMnO 6 . Field-dependent magnetization shows meta-magnetic behavior at low-temperature regions in Y 1.9 Ca 0.1 CoMnO 6 and Y 1.8 Ca 0.2 CoMnO 6 . As the concentration of Ca increased from Y 1.8 Ca 0.2 CoMnO 6 to Y 1.5 Ca 0.5 CoMnO 6 meta-magnetic behavior disappeared.