Microwave dielectric properties of tungstenbronze type like (Ba1−αSrα)6−3xR8+2xTi18O54 (R=Sm, Nd) solid solutions

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba4(Sm,Nd)9.33Ti18O54 ceramics

“…As reported, the substitution of Sr 2+ for Ba 2+ could also tune τ f to near zero for BLT ceramics, and the effect of the substitution on the Q × f value has a close relationship with the x value. Specifically, when x is far from the value of 2/3, the Q × f values could be improved with the substitution of Sr 2+ , but when x is close to the value of 2/3, they decrease . In addition, Kim et al reported that ε r could be increased by replacing the Ln ions with a small amount of Bi 3+ , and the Q × f values could be simultaneously improved slightly .…”

Effects of Sr substitution on microwave dielectric properties of Ba3LaNb3O12 ceramics

“…The reason for improving Q u × f value might be the size/distribution of the Asite cations. Larger difference in the ionic radii at A-site contributed to larger local distortion which ruined quality factor as suggested by Kagomiya et al [22]. As Sr content increased, the size difference of A-site cation between Sr 2+ (1.44 Å) and La 3+ (1.36 Å) became smaller compared to that of Ba 2+ (1.61 Å) and La 3+ ; consequently the Q u × f value became better.…”

Effects of Sm substitution on microwave dielectric properties of Ba4La9.33(Ti0.95Zr0.05)18O54 ceramics

“…La/Sm ions and Ba ions are ordering in both the rhombic sites (A1) having medium size and pentagonal sites (A2) having the largest size, respectively. While there are five different locations in A1-site [23], Sm substitution for La leads to a change of the ordering of A1-site. Disordering of cations in A1-site produces many different polars between cations and oxygen ions which reduces the Qf value [24].…”