Physical properties of new ordered bimetallic phases M0.25Cd0.75PS3 (M = ZnII, NiII, CoII, MnII)
| Autor: | Carsten Doerenkamp, C. Olea, R. C. de Santana, Patricio Fuentealba, Evgenia Spodine, Nathalie Audebrand, Hellmut Eckert, Cláudio José Magon, Héctor Aguilar-Bolados |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Band gap General Physics and Astronomy 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences law.invention Electronegativity Paramagnetism Crystallography Solid-state nuclear magnetic resonance law Phase (matter) METAIS Antiferromagnetism Physical and Theoretical Chemistry 0210 nano-technology Electron paramagnetic resonance Bimetallic strip |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/d0cp00631a |
| Popis: | Four bimetallic phases of the thiophosphate family have been synthesized by the cationic exchange reaction using a freshly prepared K0.5Cd0.75PS3 precursor phase and methanolic solutions of nitrates of the divalent cations ZnII, NiII, CoII, and MnII. All the materials were characterized by FTIR, PXRD, SEM-EDXS and (in the case of the diamagnetic compounds) by solid state NMR. For the K0.5Cd0.75PS3 precursor, the X-ray powder diffraction data suggest a modification of the structure, while solid state NMR results confirm that this phase possesses an ordered arrangement of Cd vacancies. The cationic exchange reaction achieves a complete removal of potassium ions (no potassium detected by SEM-EDXS) and re-occupation of the vacancies by divalent cations. Therefore, the obtained compounds have an average composition of M0.25Cd0.75PS3 (M = ZnII, NiII, CoII, MnII) and possess an ordered distribution of the substituent cations. Even with the paramagnetic substitution level of 25%, antiferromagnetic behaviour is present in the phases with MnII, CoII and NiII, as evidenced by dc susceptibility and in the case of the MnII substituted phase by EPR. The cooperative magnetic interactions confirm the conclusion that the paramagnetic ions adopt an ordered arrangement. The analysis by broad band impedance spectroscopy allows to attribute the conductivity in these materials to charge movements in the layers due to the difference in electronegativity of the metal ions. Zn0.25Cd0.75PS3 is the phase that shows the highest conductivity values. Finally, the band gap energies of the bimetallic phases tend to be lower than those of the single-metal phases, probably due to an overlap of the band structures. |
| Databáze: | OpenAIRE |
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