Effect of B-site Randomness on the Antiferroelectric/Relaxor Nature of the Ground State: Inelastic X-ray Scattering Study of Pb(In1/2Nb1/2)O3
Effect of B-site Randomness on the Antiferroelectric/Relaxor Nature of the Ground State: Inelastic X-ray Scattering Study of Pb(In1/2Nb1/2)O3
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DOI：
10.3938/jkps.59.2509
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发表时间：
2011-09-01
影响因子：
0.6
通讯作者：
Yasuda, Naohiko
中科院分区：
文献类型：
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作者：
Ohwada, Kenji;Fukuda, Tatsuo;Yasuda, Naohiko
PB(In1/2Nb1/2)O-3(PIN)可以是反铁电体(AFE)、铁电体(FE)或弛豫体，这取决于钙钛矿B位的随机性。为了阐明B位随机性的影响，我们研究了没有B位随机性的有序PIN(O-PIN，AFE)的动力学，这将使我们清楚地了解由于B位随机性而导致的基态的AFE/弛豫性质。准弹性(QE)散射在伽马点附近出现临界减速，而横声波(TA)模在有限波数位置(而不是伽马点)有软化趋势。AFE的相变温度(T-N类似于450K)。另一方面，横向光学(TO)模在伽马点附近向低温方向软化，在T-N处没有明显的反常。这些结果表明AFE相变与TA模和QE散射的起源有关，而AFE有序背后存在铁电关联。在此基础上，讨论了B位随机性的影响。
Pb(In1/2Nb1/2)O-3 (PIN) can be antiferroelectric (AFE), ferroelectric (FE) or a relaxor depending upon the perovskite B-site randomness. In order to clarify the effect of B-site randomness, we studied the dynamics of ordered PIN without B-site randomness (O-PIN, AFE), which will give us a clear picture of the AFE/relaxor nature of the ground state due to B-site randomness. The quasielastic (QE) scattering shows a critical slowing down near the Gamma-point and the transverse acoustic (TA) mode shows a softening trend at a finite wavenumber position (not at the Gamma-point) towards. the AFE phase transition temperature (T-N similar to 450 K). On the other hand, the transverse optic (TO) mode shows a softening near the Gamma-point toward low temperature with no clear anomaly at T-N These results indicate that the AFE phase transition is associated with the TA mode and the origin of the QE scattering while a ferroelectric correlation exists behind the AFE ordering. The effect of B-site randomness is finally discussed on the basis of the results.