Effect of cation occupancy on crystal structure and microwave dielectric characteristics of spinel-structured (1-x)Zn2TiO4-xli2MgTi3O8 ceramics

Excellent spinel microwave dielectric ceramics (1-x)Zn2TiO4-xLi(2)MgTi(3)O(8) (ZTLMTx, x = 1/3 and 2/3) were prepared at relatively low densification temperatures of 1100 degrees C and 1080 inverted perpendicular C, respectively. A disordered cubic phase with space group Fd-3m was formed at x = 1/3, whereas an ordered cubic phase with space group P4(3)32 was formed at x = 2/3. The ceramics at x = 1/3 and 2/3 exhibited promising microwave dielectric properties of epsilon(r) = 18.27 and 22.96, Q x f = 91,877 GHz and 75,186 GHz, and tau(f) = 42.3 ppm/degrees C and 21.05 ppm/degrees C, respectively. The large deviation between the experimental epsilon(r) and theoretical epsilon(th) of 1/3 and 2/3 ceramics were 18.3 % and 57 %, respectively, due to the underestimation of the ionic polarizability of Ti4+. The difference in their epsilon(r), Q x f, and tau(f) were discussed by the structure, FWHM of A(1g), lattice energy and bond energy in detail.