J. Korean Ceram. Soc. > Volume 40(4); 2003 > Article
 Journal of the Korean Ceramic Society 2003;40(4): 354. doi: https://doi.org/10.4191/kcers.2003.40.4.354
 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 Technology1New Materials Evaluation Center, Korea Research Institute of Standard and Science ABSTRACT 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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