Microwave dielectric properties of Mn-doped BaO–(Nd0.7,Sm0.3)2O3–4TiO2 ceramic sintered in a reducing atmosphere
| Autor: | Ying-Chieh Lee, Wen-His Lee |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Materials science
Process Chemistry and Technology Reducing atmosphere Doping Analytical chemistry Dielectric Microstructure Surfaces Coatings and Films Electronic Optical and Magnetic Materials visual_art Phase (matter) Materials Chemistry Ceramics and Composites visual_art.visual_art_medium Ceramic Composite material Temperature coefficient Solid solution |
| Zdroj: | Ceramics International. 36:181-185 |
| ISSN: | 0272-8842 |
| DOI: | 10.1016/j.ceramint.2009.07.006 |
| Popis: | The effect of MnCO 3 doped from 0 to 55 mol% into BaO–(Nd 0.7 Sm 0.3 ) 2 O 3 –4TiO 2 (BNST) sintered in a reducing atmosphere on the microstructure and electrical properties was studied. Mn 3+ completely substituted into Ti 4+ -sites of BNST to form a solid solution, so there is no second phase until 42 mol% which is the maximum solubility. Mn ( 43 mol%), the second Mn-rich phase due to excess of Mn 3+ substituted into Ti 4+ -site, corresponding to original BaO–(Nd 0.7 Sm 0.3 ) 2 O 3 –4TiO 2 (1 1 4) phase, is formed. Mn (>43 mol%)-doped BNST sintered in a reducing atmosphere is in an insulating state because the concentration of the acceptors is higher than that of liberated free electron, so the insulation resistance becomes high and tan δ becomes low. The formation of the second Mn-rich phase affects Q × f factor and temperature coefficient of capacitance (T.C.C.) of BNST significantly. |
| Databáze: | OpenAIRE |
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