【摘要】 测量了(1-x％)镁铌酸铅-x％钛酸铅(1≤x≤11)(简称PMNTx)陶瓷样品的介电常数、内耗和Young’s模量.观测到在Tm温度附近,即在介电常数达到最大值时,出现一个内耗峰,并且模量发生软化.这反映了极化纳米微畴的弛豫.对于PMNTx(5≤x≤11)的样品,在Tm温度以下的某个温度出现附加的内耗峰和Young’s模量的异常,表明样品中发生了自发的弛豫铁电到铁电(简称R—F)的相变.对R—F相变的机制进行了讨论.更多还原

【Abstract】 The dielectric constant, internal friction and Young’s modulus of (1-x%) Pb(Mg1/3Nb2/3)O3-x%PbTiO3 (1≤ x ≤11) (PMNTx) ceramics have been measured. Internal friction (IF) peak and Young’s Modulus (E) softening around the temperature Tm,where the dielectric permittivity reaches maximum, were observed. It can be explained by the relaxation of the polar nano-regions (PNRs). What’s more, for PMNTx (5≤ x ≤11) a spontaneous relaxor-ferroelectric (R-F) phase transition is evidenced by an additional IF peak and an anomaly of Young’s modulus appearing at the temperature below Tm. The mechanism of R-F phase transition is discussed.更多还原