| Microwave Dielectric Characteristics of Aluminum Magnesium Tantalate Based High Q Ceramics |
| Ji-Won Park, Hwack-Joo Lee1, Seok-Jin Yoon, Hyun-Hai Kim |
Thin Film Materials Research Center, Korea Institute of Science and Technology
1New Materials Evaluation Center, Korea Research Institute of Standard and Science |
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| ABSTRACT |
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The microwave dielectric characteristics of (1-x)(Al$_$$frac{1}{2}$/Ta$_$$frac{1}{2}$/)O$_2$-x(Mg$_$1/3/Ta$_$2/3/)O$_2$ (0$leq$x$leq$1.0) ceramics were investigated by crystalstructure, variations of ionic polarizability, and microstructures. As x increased, (1-x)(Al$_$$frac{1}{2}$/Ta$_$$frac{1}{2}$/)O$_2$-x(Mg$_$1/3/Ta$_$2/3/)O$_2$ transformed to tetragonal structure. Because the ionic radius of (Mg$_$1/3/Ta$_$2/3/)$^$4+/was slightly bigger than one of (Al$_$$frac{1}{2}$/Ta$_$$frac{1}{2}$/)$^$4+/, the cell parameters increased with increase of (Mg$_$1/3/Ta$_$2/3/)O$_2$concentration and coincided with prediction of the molecular additivity rule. As x increased, the compositions revealed ordered phase and were of single phase above 60 mol%. The increase of the ordered phase and grain size enhanced the Q and when ordering was completed at x over 0.6, the grain size was major factor for the increase in the a. Though the grain size increased, however, the porosity deteriorated the q. Therefore, the a depended on the order/disorder, the porosity, and the grain size in regular order. |
| Key words:
Microwave dielectric materials, Dielectric constant, Quality factor, Ionic polarizability, Ordering |
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