Effect of electronegativity on microwave dielectric properties of MgTi _{1 −x} (A _{1 / 3} Sb _{2 / 3} ) _x O ₃ (A = Mg ²⁺ , Zn ²⁺ ) ceramics

Abstract Microwave dielectric properties of MgTi _{1− x} (A _1/3 Sb _2/3 ) _x O ₃ (A = Mg ²⁺ , Zn ²⁺ , 0 ≤ x ≤ 0.125) ceramics were investigated as a function of the electronegativity difference ( X ) between (A _1/3 Sb _2/3 ) ⁴⁺ ions (A = Mg ²⁺ , Zn ²⁺ ) and O ²⁻ ion. A single phase with an ilmenite structure was detected for the specimens sintered at 1450°C for 4 hours in the entire range of compositions. With the substitution of (A _1/3 Sb _2/3 ) ⁴⁺ ions (A = Mg ²⁺ , Zn ²⁺ ) at Ti ⁴⁺ ‐sites of MgTiO ₃ , the quality‐factor ( Qf ) values of the specimens increased up to x = 0.05 mol, and then decreased with the further substitution owing to the electronegativity difference ( X ) between the (A _1/3 Sb _2/3 ) ⁴⁺ ions (A = Mg ²⁺ , Zn ²⁺ ) and Ti ⁴⁺ ion. The specimens with (Mg _1/3 Sb _2/3 ) ⁴⁺ ions exhibited higher Qf values than those with (Zn _1/3 Sb _2/3 ) ⁴⁺ ions. These results could be attributed to the smaller electronegativity of (Mg _1/3 Sb _2/3 ) ⁴⁺ (1.80) than that of (Zn _1/3 Sb _2/3 ) ⁴⁺ (1.92). The dependences of the microwave dielectric properties on the structural characteristics of the MgTi _{1− x} (A _1/3 Sb _2/3 ) _x O ₃ ceramics were also discussed.