Relaxor Properties of Barium-Strontium Niobate Ceramics

Effects of illumination on the dielectric response of barium-strontium niobate ceramics

“…As seen from figure 1, a considerable relaxation of polarization is displayed by the rounded PL at 62 °C in agreement with the conclusion [6] of an essential effect of conductivity around T m of the material. The same general pattern of PL is maintained at 23 °C; only at T < T room (14 °C) a typical response of a FE material is displayed by the Rayleigh pattern of PL at amplitude E<E C (E C -coercive field) [6]. Comparing the loops in dark and illuminated sample at 62 °C reveals a decrease of the loop area -narrowing of the loops caused by illumination.…”

“…In the other case -as flattening of ε e  ff (E) at E ≈ 8-10 kV/cm (c) and as a bending point on the ε" eff (E) curve in the 7-8 kV/cm amplitude range (d). Behaviour of the parameters of SBN-75 at 62 °C, which is below T m ≈ 110 °C [6], might point to saturation of polarization P(E) as the cause of the additional maximum of ε e  ff (E). The field intensity at which the broad maximum appears on ε" eff (E) would correspond to coercive field E c when the material in the FE state starts "switching" under applied field exceeding E c .…”

“…The selected temperatures cover the range of the broad phase transition in SBN-75 ceramics as found [6] from ε′(T) and ε″(T) measurements at low field intensities. As seen from figure 1, a considerable relaxation of polarization is displayed by the rounded PL at 62 °C in agreement with the conclusion [6] of an essential effect of conductivity around T m of the material.…”

“…The selected temperatures cover the range of the broad phase transition in SBN-75 ceramics as found [6] from ε′(T) and ε″(T) measurements at low field intensities. As seen from figure 1, a considerable relaxation of polarization is displayed by the rounded PL at 62 °C in agreement with the conclusion [6] of an essential effect of conductivity around T m of the material. The same general pattern of PL is maintained at 23 °C; only at T < T room (14 °C) a typical response of a FE material is displayed by the Rayleigh pattern of PL at amplitude E<E C (E C -coercive field) [6].…”