Dielectric Properties of Ba_1−xCa_xTi₂O₅ Prepared by Arc Melting

Abstract

b-axis-oriented CaO substituted polycrystalline BaTi₂O₅, Ba_1−xCa_xTi₂O₅ (BCT₂, x=0 to 0.10), was prepared by arc melting. The dielectric property of BCT₂ was investigated by an AC impedance method. The lattice parameters of BCT₂ decreased with increasing CaO content in the range up to around x=0.08. The remnant polarization (P_r) and coercive electric field (E_c) of polycrystalline BCT₂ at x=0.08 were 1.6×10⁻² Cm⁻² and 0.4×10⁶ Vm⁻¹, respectively. The P_r of polycrystalline BCT₂ was larger than that of BaTi₂O₅ (BT₂, P_r=0.9×10⁻² Cm⁻²), while the E_c of BCT₂ was smaller than that of polycrystalline BT₂ (E_c=0.7×10⁶ Vm⁻¹). The permittivity of BCT₂ showed the maximum value of 4950 at x=0.02 and a Curie temperature (T_c) of 736 K. The T_c of BCT₂ decreased from 750 to 665 K with increasing CaO content from 0 to 0.10.