Correlation of microwave dielectric properties and normal vibration modes of xBa(Mg1/3Ta2/3)O3-(1-x)Ba(Mg1/3Nb2/3)O3 ceramics:: I.: Raman spectroscopy

Micro-Raman measurements of xBa(Mg1/3Ta2/3)O-3-(1-x)Ba(Mg1/3Nb2/3)O-3 perovskite ceramics, with x=0, 0.25, 0.50, 0.75, and 1.0, were taken at room temperature. Raman results clearly show the 1:2 ordered structures of these compounds. Four A(1g) and five E-g Raman modes were unambiguously assigned. The A(1g)(O) phonon of the oxygen-octahedron stretch mode, which possesses the largest energy and width of all the observed Raman phonons, significantly influences the microwave dielectric properties of the materials. A higher vibration frequency of A(1g)(O) mode results in a lower dielectric constant, and a wider width of the mode corresponds to a lower Qxf value. (C) 2003 American Institute of Physics.