Cubic phase stability, optical and magnetic properties of Cu-stabilized zirconia nanocrystals
| Autor: | P. Pramanik, Kelly L. Pisane, Subhash Thota, Mohindar S. Seehra, D. C. Joshi, Alessandra Romero, Sobhit Singh, Ayan Mallick |
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| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Materials science Acoustics and Ultrasonics Doping Analytical chemistry 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Magnetic susceptibility Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Crystallinity law 0103 physical sciences Calcination Cubic zirconia Crystallization 0210 nano-technology Thermal analysis Monoclinic crystal system |
| Zdroj: | Journal of Physics D: Applied Physics. 51:225304 |
| ISSN: | 1361-6463 0022-3727 |
| DOI: | 10.1088/1361-6463/aac004 |
| Popis: | By means of experimental and ab initio investigations, we report on the cubic phase stability of Cu doped zirconia (ZrO2) at room temperature, and further characterize its structural, optical and magnetic properties. Various compositions of Zr1−x Cu x O2 (0.01 ≤ x ≤ 0.25) nanocrystallites of average size ~16 nm were synthesized using co-precipitation technique. Thermal analysis and kinetics of crystallization revealed that the cubic phase at ambient temperature can be stabilized by using a critical calcination temperature of 500 °C for 8 h in air and a critical composition of . For x x c , the monoclinic CuO emerges as a secondary phase with shrinkage of unit-cell volume with increasing the Cu content. At x = 0.05 and 500 °C calcination temperature, we observe a high degree of cubic crystallinity which breaks down into monoclinic phase with increasing calcination temperature beyond 550 °C. Electron magnetic resonance studies provide evidence for the substitution of Cu2+ (2D5/9,3d9) ions at Zr4+ sites with g, g and average g a = ( + 2)/3 ~ 2.1. The temperature dependence of magnetic susceptibility measurements from 2 K to 300 K exhibits Curie–Weiss behaviour whose analysis using g a = 2.1 and spin S = 1/2 yields x = 0.028 and x = 0.068 for the nominal x = 0.05 and x = 0.20 samples, respectively. This magnetic analysis confirms the findings from x-ray diffraction that only a part of Cu is successfully doped into cubic phase of Cu-doped ZrO2. The optical bandgap decreases with increasing x, which is due to the emergence of Cu-d states at Fermi-level near the valence bands, thus making Cu-doped zirconia a hole doped (p-type) semiconductor. |
| Databáze: | OpenAIRE |
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