Structure, magnetism, electrical transport, and optical properties of the electron-doped quasi-2D manganates LaxCa3-xMn2O7
| Autor: | Baojuan Kang, Zhenjie Feng, Jun-Yi Ge, Shixun Cao, Jincang Zhang, Chao Xu, Fei Chen |
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| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Spin glass Materials science Magnetic structure Magnetism Process Chemistry and Technology Doping 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Crystallography X-ray photoelectron spectroscopy Ferromagnetism 0103 physical sciences Materials Chemistry Ceramics and Composites Cluster (physics) Antiferromagnetism 0210 nano-technology |
| Zdroj: | Ceramics International. 45:20613-20625 |
| ISSN: | 0272-8842 |
| Popis: | We have successfully synthesized La x Ca 3- x Mn 2 O 7 ( x = 0, 0.3, 0.5, 0.7, 0.9) samples with Ruddlesden-Popper (RP) structure in Cmcm space group. Meanwhile, X-ray photoelectron spectroscopy (XPS) results indicate that the concentrations of Mn 3+ and oxygen vacancy defects V O are enhanced with increasing doping. As a result, the magnetic and electrical transport properties can be tuned accordingly. With increasing doping, the antiferromagnetic (AFM) interaction was gradually weakened along with the enhancement of ferromagnetic (FM) interaction, and eventually the magnetic structure evolves from G-type to C-type. Our comprehensive experimental studies all propose that these manganates tend to intrinsically separate into AFM matrix state, spin glass regions, and FM cluster regions at lower temperature, which results from the competition between FM (Mn 3+ -O 2- -Mn 4+ ) and AFM (Mn 3+ -O 2- -Mn 3+ or/and Mn 4+ -O 2- -Mn 4+ ) domains. Especially, this behavior can be modulated by La doping, i.e. the spin glass regions and FM cluster regions tend to be enhanced with increasing La doping. According to molecular field theory, it indicates that the stronger Dzyaloshinskii-Moriya (DM) interaction effect and canted antiferromagnetism (CAFM) only present in C-type structure. The electrical transport properties can be also modulated by La doping, attributed to the changes of the local states around the mobility edge. Those results are quite essential for understanding the evolution of the complicated magnetoelectric properties in the RP La x Ca 3-x Mn 2 O 7 ceramics. |
| Databáze: | OpenAIRE |
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