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首页> 外文期刊>Applied Magnetic Resonance >Polarons and charge-transfer vibronic excitons in ferroelectric oxides: EPR and photoluminescence studies of PbxNbyOz ceramics
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Polarons and charge-transfer vibronic excitons in ferroelectric oxides: EPR and photoluminescence studies of PbxNbyOz ceramics

机译：铁电氧化物中的极化子和电荷转移的激子激子：PbxNbyOz陶瓷的EPR和光致发光研究

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yWe performed a simulation of the chemical fluctuation regions in the lead-magnesium-niobate-like relaxors by growing PbxNbzOz ceramics. The coexistence of PbxNbyOz clusters with different chemical composition that is inclusive of Nb5+ as well as Nb3+ ions was assumed. The existence of mobile polaronic pseudo-Jahn-Teller holes on the oxygen ions in different PbxNbyOz clusters has been suggested by the electron paramagnetic resonance (EPR) experiment. Here light- induced EPR and EPR motional averaging effects related with such polaronic holes have been manifested. The appearance of new paramagnetic centers (S = 5/2, 3/2, 1/2) related with Cr3+ impurities at the Nb5+ sites with trapped hole pairs (hole bipolarons), the charge compensation and the exchange effect have been proposed as explanation for the results of the EPR experiment. The charge-transfer vibronic excitons with O -> Nb5+ charge transfer were directly detected by photoluminescence studies. The R-line in the Cr3+ impurity photoluminescence evidences the appearance of the Cr3+ ion in such matrices.
机译：y我们通过生长PbxNbzOz陶瓷对铅铌铌酸盐样弛豫器中的化学波动区域进行了模拟。假定具有不同化学组成（包括Nb5 +和Nb3 +离子）的PbxNbyOz簇共存。通过电子顺磁共振（EPR）实验表明，在不同的PbxNbyOz团簇中，氧离子上存在可移动极化子伪Jahn-Teller孔。在此已经证明了与此类极化子孔有关的光诱导EPR和EPR运动平均效应。提出了与Cr3 +杂质有关的新的顺磁性中心（S = 5 / 2、3 / 2、1 / 2）的出现，这些Nb5 +位点具有被困的空穴对（空穴双极子），电荷补偿和交换效应，以此作为解释。 EPR实验的结果。通过光致发光研究直接检测出具有O-> Nb5 +电荷转移的电荷转移振动子激子。 Cr3 +杂质光致发光中的R线证明了此类基质中Cr3 +离子的出现。

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