Dielectric properties of MgTi1?x(Zn1/3B2/3)xO3 (B = Nb5+, Ta5+) ceramics at microwave frequencies

摘要

p class="global-para-14" pMicrowave dielectric properties of MgTisub1?/sub subx/sub (Znsub1/3/subBsub2/3/sub) subx/sub Osub3/sub (B = Nbsup5+/sup, Tasup5+/sup, 0.025 ≤ x ≤ 0.125) were investigated based on their structural characteristics and the electronegativity difference of the constituent ions. For the specimens of MgTisub1?/sub subx/sub (Znsub1/3/subNbsub2/3/sub) subx/sub Osub3/sub, a single phase of the rhombohedral ilmenite structure appeared for the entire range of compositions (0.025 ≤ x ≤ 0.125), while MgTisub1?/sub subx/sub (Znsub1/3/subTasub2/3/sub) subx/sub Osub3/sub showed a single phase of ilmenite structure up to x = 0.075, and then MgTisub2/subOsub5/sub was detected as a secondary phase on further substitution of (Znsub1/3/subTasub2/3/sub)sup4+/sup at Tisup4+/sup-site of MgTiOsub3/sub. Quality factor value increased with the electronegativity difference up to an electronegativity difference of 2.015 and was dependent on the degree of covalent character of the bond. Temperature coefficient of resonant frequency decreased with an increase in oxygen octahedral distortion. Dielectric constant of the specimens did not exhibit any remarkable change with the substitution of (Znsub1/3/subBsub2/3/sub)sup4+/sup at Tisup4+/sup-site of MgTiOsub3/sub./p /p