Field-induced dielectric properties of BZT ceramics

In the present study are reported the measurements of the complex dielectric permittivity in the lead-free isovalent xBaZrO3-(1-x)BaTiO3 (BZT-x, x = 0.1, 0.4, 0.5, 0.9) ceramic solid solution [1,2] performed in frequency range from 1 Hz to 1 MHz for field-cooled (FC) and zero-field-heated (ZFH) (after field cooling) regimes in the temperature range 300 - 10 K. In addition, in the same temperature range the dielectric hysteresis loops were measured in 1 Hz - 50 Hz frequency range using the standard Sawyer-Tower bridge. Also the pyro-current measurements (5 K/min heating after cooling with 5 - 15 kV/cm applied electric field) were obtained using the Electrometer High Resistance Meter KEITHLEY 6517A. Polarization obtained from pyro-current was calculated by subtraction the background thermo-activated current related to charged defects and compared with remanent polarization obtained from the hysteresis loops. In the BZT-0.4 and 0.5 relaxor compositions the applied electric field reduced the frequency dispersion of the dielectric permittivity and the dielectric loss peak broadened. Appearance of the polar nanoregions and their manifestation in the field-induced dielectric spectra was discussed from the point of view of difference between relaxors and dipolar glasses [3,4,5,6]. References [1] Q. Zhang, J. Zhai, and L. B. Kong, J. Adv. Dielectr. 2, 1230002 (2012). [2] T. Maiti, R. Guo, and A. S. Bhalla, Ferroelectrics 425, 4 (2011). [3] D. Nuzhnyy et al., Phys. Rev. 86, 014106 (2012). [4] J. Petzelt et al. Ferroelectrics 469, 14 (2014). [5] J. Petzelt et al., Phase Transitions 88, 320 (2015). [6] C. Filipic, Z. Kutnjak, R. Pirc, G. Canu, and J. Petzelt., subm. to Phys. Rev. B.