Temperature compensation effects of TiO2 on Ca[(Li1/3Nb2/3)0.8Sn0.2]O3−δ microwave dielectric ceramic

Abstract

The crystal structure and dielectric properties of TiO2-modified Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] microwave ceramics are investigated in the present paper. The crystal structure is probed by XRD patterns and their Rietveld refinement, results show that a single perovskite phase is formed in TiO2-modified Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] ceramics with the crystal structure belonging to the orthorhombic Pbnm 62 space group. Raman spectra results indicate that the [Formula: see text]-site order–disorder structure transition is a key point to the dielectric loss of TiO2-modified Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] ceramics at microwave frequencies. After properly modified by TiO2, the large negative temperature coefficient of Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] ceramic can be compensated and the optimal microwave dielectric properties can reach [Formula: see text] = 25.66, [Formula: see text] = 18,894 GHz and TCF = −6.3 ppm/[Formula: see text]C when sintered at 1170[Formula: see text]C for 2.5 h, which manifests itself for potential use in microwave dielectric devices for modern wireless communication.