Dielectric behavior of a lead-free electroceramics Ba1−xEr2x/3(Ti1−yZry)O3
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Lead-free electroceramics samples of composition Ba1−xEr2x/3(Ti1−yZry)O3 (BETZ) with x = 0.01 and 0.02 and 0.20 ≤ y ≤ 0.35 have been elaborated by solid-state reaction technique. X-ray diffraction at room temperature discloses a single perovskite phase with a cubic symmetry. Dielectric measurements were carried out in the ranges (80–445 K) and (102–106 Hz) of temperature and frequencies respectively. The ceramics exhibited normal and/or relaxor ferroelectric properties then some of them have very interesting dielectric characteristics in the vicinity of room temperature. A wide dielectric anomaly combined to the dielectric maxima shift toward a higher temperature with increasing frequency denotes either a diffuse phase transition or relaxor behavior in some ceramics. For any erbium concentration, when titanium is substituted by zirconium, the temperature of the permittivity maximum TC (Tm) and the maximum permittivity (ε′rmax) decreases while ΔTm(f)= [Tm(106 Hz) − Tm(102 Hz)] and tan δ increase. The diffuse phase transition parameters were calculated from the modified Curie–Weiss law linear fit. Further a relaxor nature was confirmed and endorsed by a good fit to the Vogel–Fülcher relation.
The authors are grateful to N. Geoffroy for his help in XRD experiments and helpful discussion and to Dr. F. Herbst for SEM and EDX observations.
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