Investigation of electrical properties and PTCR effect in double-donor doping BaTiO₃ lead-free ceramics

Abstract

Utilizing the conventional approach, the positive temperature coefficient of resistivity (PTCR) performance of lead-free ceramics based on (1 − x%)(Ba_1−y Y _y )(Ti_1.011−z Nb_0.001Mn _z )O₃ − x%(Bi_0.5Na_0.5)TiO₃ (BBNTx) was examined. The BBNTx ceramics were prepared using the double donor dopant under firing at 1,350°C for 120 min in the air. The findings exhibited that when the Y³⁺ concentration elevates, the room-temperature resistivity of 99%(Ba_1−y Y _y )(Ti_1.011−z Nb_0.001Mn _z )O₃ – 1%(Bi_0.5Na_0.5)TiO₃ (BBNT1) samples initially falls and subsequently elevates. Moreover, the critical content of the samples is 0.15 mol%. Furthermore, the samples’ resistance jumping ratio can be effectively improved by adding Mn²⁺. The manganese dioxide level of 0.05 mol% yields the greatest resistance-jumping ratio. Besides, the impact of (Bi_0.5Na_0.5)TiO₃ (BNT) concentration on ceramics’ Curie temperature was examined in the work. Therefore, good free-lead PTCR thermistors were successfully prepared by doping 3% BNT, with a resistance jump of 4.1 magnitude.