Dielectric Properties of (PbCa)(MeNb)O₃ at Microwave Frequencies

Abstract

We have investigated the dielectric properties up to microwave frequencies of ceramics represented as (Pb1-x Ca x )-(Me m Nb1-m )O3 where Me is selected from Li, Na, Mg, Zn, Ni, Co, Fe, Y, Yb, Al and Cr. High Q values and small temperature coefficients of resonant frequency were obtained in (PbCa)(Mg1/3Nb2/3)O3, (PbCa)(Ni1/3Nb2/3)O3 and (PbCa)-(Fe1/2Nb1/2)O3 with perovskite structure. These dielectric constants and the Q values for a near-zero temperature coefficient are εr=73 with Q=1330, εr=59 with Q=1700 and εr=91 with Q=1650, respectively. The other ceramics with smaller amounts of perovskite phase had degraded characteristics, i.e., low Q values or large temperature coefficients. In lead- and calcium-based perovskite, it seems that the high dielectric constant occurs due to Pb content in A-sites and smaller average ion radius in B-sites.

Intrinsic factors affecting the microwave dielectric properties of Mg2Ti1−(Mg1/3Sb2/3) O4 ceramics

“…[27] reported that the K value is correlated with the average ionic radius of the B-site in perovskite ceramics. In addition, Kato et al [28] suggested that a low K value results from a decrease in the movement of the ions at the Ti-site The volume of the M-site varies with both a and u, and is calculated as follows:…”

Variation of Dielectric and Electrical Properties of Zr-Substituted Lead Calcium Iron Niobate with Temperature and Frequency

“…1 The PCFN has high e r and a small temperature coefficient of relative permittivity at microwave frequencies along with a high loss tangent (tan d). 7 In order to reduce the losses and to make them suitable for these electronic devices, several attempts have been made to tailor the properties of these materials by the substitution at A-and/or B-sites. [10][11][12][13][14][15] In complex perovskites, B¢ and B¢¢ ion pairs show a variety of physical properties; 16 therefore, B-site substitution has been preferred in the present research work.…”

Influence of Zr substitution on structural, dielectric and magnetic behavior of lead calcium iron niobate

“…PCFN and PCFN based solid solutions are the promising materials for microwave applications [33][34][35]. Several attempts have been made to design and develop these materials by substituting various isovalence and hetrovalence elements/atoms at both A-and/or B-site [21,22,[36][37][38].…”