Dielectric behavior of betaine arsenate/phosphate mixed crystals (BA_xBP_1−x) in an electric bias field

Abstract

We have extended earlier experiments made on mixed crystals of ferroelectric betaine arsenate (BA) and antiferroelectric betaine phosphate (BP), BA_xBP_1−x, by observing the anomalies in the real part of the dielectric function (ε) and the dissipation factor (tanδ=ε″/ε′) at various temperatures (20 K<T<300 K) and frequencies (0.1 kHz< v < 100 kHz) under several hydrostatic pressures (p<350 MPa) and electric bias fields (E<8.2 kV cm⁻¹) for x=0.24 and 0.94, in order to obtain information about the stability of the different regions in the phase diagrams and the dynamics of the system, with special focus on the low temperature glasstype freezing.