Abstract
(Bi0.5Na0.5)Ti03-based materials have attracted widespread attention due to large electro-strain,large remnant polarization(Pr)and high Curie temperature(Tc),but the existence of inherent depolarization temperature(Td)limits the temperature stability and application temperature range.In this work,we find that K/Na ratio can regulate Td(from 90℃to 246℃)of the ceramics,which confirms that the increase of K substitution can effectively improve the temperature stability of the material.The phase structure and electrical properties of Bi0.5(Na1-xKx)0.5Ti03(BNKTx)ceramics can be well modulated by changing K/Na.In addition,BNKTx system exhibits excellent piezoelectric response at morphotropic phase bound-ary(MPB)of 20％BKT content(d33=180 pC/N),where rhombohedral(R3c)phase and tetragonal(P4bm)phase coexist in MPB.With K further substitution,BNKTx ceramics transform into tetragonal phase,and the domain size grows due to the structural transition from short-range-correlated P4bm to long-range-correlated P4mm.The deferment of Td is also tightly related to the increase of P4mm/P4bm ratio.This work can provide an effective way to tailor depolarization temperature and electrical properties of BNT-based ceramics.
基金项目
国家自然科学基金(51972215)
国家自然科学基金(52061130216)
Royal Society is thanked for a Newton Advanced Fellow-ship award(NAF\R1\201126)
Central Funds Guiding the Local Science and Technology Development of Sichuan Province(2021ZYD0022)
Analytical&Testing Center of Sichuan University()
万方数据