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We report a study of the structural and thermal characteristics of calcium titanate alloys Ca[(Li 1/3 Nb 2/3 ) x Ti 1−x ]O 3−δ (abbreviated as CNLTO). CNLTO alloys were prepared using a new procedure in the solid-state reaction method. Then they were studied using x-ray diffraction, Raman scattering spectroscopy and microwave properties. The symmetry of the atomic structure of the samples belongs to the spatial group Pbnm, showing orthorhombic structure. The microwave dielectric properties of CNLTO for samples ball-milled with the ratios of 1 and 2.4 balls g −1 , calcinated at 900 • C (with two different times of exposure: 3 and 5 h) and sintered at 1000 and 1100 • C (during 3 h) were investigated. For both calcination treatments (900 • C, during 3 and 5 h), the dielectric permittivity decreased with decreasing titanium concentration. It was also observed that a higher temperature of calcination contributes to increasing the ε r values. Dielectric permittivity values in the range 10-50 were obtained. We noted a decrease in the temperature coefficient of resonant frequency (τ f ) with an increase of the x value (titanium substitution). CNLTO has excellent microwave properties with τ f close to zero for concentrations between 0.925 and 0.950.

This paper presents a study of the structure and microwave properties of [Formula: see text] substituted into the Ti 4+ site of calcium titanate ceramics. The structural and dielectric properties of solid solutions in CaTi 1-x( Nb 1/2 Fe 1/2)x O 3, was done. The microwave dielectric properties of solid solutions in CaTi 1-x( Nb 1/2 Fe 1/2)x O 3, (CNFTOX with x = 0.1 to x = 1) is discussed. The modified CaTiO3 (CTO) ceramics were prepared by a new procedure in the solid-state method. A study of the variations of the ball-milling process was done. The calcinations were done at 900°C for 3 and 5 h respectively, and the sintering at 1100°C, for 3 h. The structural property studies of the ceramics were investigated by X-ray diffraction (XRD) and Raman spectroscopy. The X-ray analysis showed that all samples have an orthorhombic structure. The refinement analysis of all samples were also duly performed and discussed. The nine scattering bands centered at 183, 227, 247, 288, 338, 470, 490 and 805 cm-1 were observed. Several peaks presented a small shift as a function of the x value. All Raman spectra in the studied samples showed a small band at 805 cm-1, which is a function of the x value. The dielectric permittivity and loss at microwave frequencies (MW) were investigated. For both calcination treatments (900°C for 3 and 5 h), the dielectric permittivity decreased with a decrease of the titanium content. Dielectric permittivity values in the range of 20 to 80 were obtained. It was also observed that a higher number of balls in the milling process contribute to the increase of the εr values. The CNFTO has an excellent microwave property at x = 0.6, with a temperature coefficient of resonant frequency (τf) near zero (τf = 2.8 ppm/°C).