DIELECTRIC INVESTIGATIONS OF LANTHANIDES (Ln = Sm, Nd AND Gd) SUBSTITUTED BARIUM TITANATE MICROWAVE CERAMICS

ABSTRACT

Dielectric properties have been investigated and compared for three series of ceramic compounds based on complex oxides with molecular formula Ba_{6 − 3x} Ln_{8 + 2x} Ti₁₈O₅₄ with Ln (lanthanide) = Sm, Nd and Gd and x = 0.0 – 0.7. X-Ray diffraction (XRD) was employed to study the crystal structure of the sintered ceramics. Fired densities have been observed to be almost constant up to a certain composition then decreased with an increase in x. Values of dielectric constant (ε′) and loss tangent (tanδ) were decreased with increased composition as well as frequency. The temperature coefficient of resonant frequency (τ_f) was estimated in the temperature range of 20°C to 80°C.

Keywords:

• ceramics
• X-ray diffraction
• lattice constant
• dielectric constant
• loss tangent
• temperature coefficient of resonant frequency