EFFECTS OF IMPURITIES ON DIELECTRIC-PROPERTIES OF FLUOROZIRCONATE GLASSES AT MICROWAVE-FREQUENCIES

The dielectric properties of fluorozirconate glasses doped with differ ent impurities have been investigated in the frequency region of 3.0-1 2.5 GHz using a microwave network analyzer. For glasses containing oxi de impurities such as PbO, SiO2, and TiO2, the position of the dielect ric resonance, which is observed in the pure fluoride glass, shifts to higher frequencies. Amplitudes of the resonance peaks also become muc h smaller. The oxide impurities are observed to exist as large numbers of tiny precipitates in the glasses. When the glasses are doped with InF3, the position of the resonance peak shifts to a higher frequency but the amplitude of the peak remains unchanged. The InF3 may be subst ituted for AlF3 in the glasses. A higher half-resonance width is obser ved in the doped fluorozirconate glasses. The changes in the dielectri c properties are attributed to the different behaviors of the impuriti es, which affect the structural interunit vibration in the fluoride gl asses. (C) 1998 American Institute of Physics. [S0021-8979(98)04802-6] .