Ultrasonic evidence for short-range charge-ordering state in the low-doping regime of La1– x Sr x FeO3 (1/3 ≤ x ≤ 0.45)
Ultrasonic evidence for short-range charge-ordering state in the low-doping regime of La1– x Sr x FeO3 (1/3 ≤ x ≤ 0.45)
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DOI：
10.1080/01411594.2012.683868
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发表时间：
2012-08
影响因子：
1.6
通讯作者：
K. Hui;S. Shuai;Zhu Changfei
中科院分区：
文献类型：
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作者：
K. Hui;S. Shuai;Zhu Changfei
在单相多晶 La1– x Sr x FeO3 (x = 1/3, 0.4, 0.45) 中测量了纵向超声速度 (V) 和 10 MHz 频率下的衰减，以及磁化强度和电阻率。从高温冷却后，在所有样品中都观察到 V 值略有软化和剧烈的硬化，并且这种硬化与大的衰减峰同时发生。 V 的相对增加与 Sr 浓度成正比，这意味着这种异常与 Fe4+ 密切相关。然而，在此温度范围内未发现磁性能和电性能发生明显变化。分析表明，这一特征可能是由Fe4+的Jahn-Teller效应引起的，对应于短程电荷有序态的形成。
The longitudinal ultrasonic velocity (V) and attenuation at a frequency of 10 MHz, as well as magnetization and resistivity, have been measured in the single-phase polycrystalline La1– x Sr x FeO3 (x = 1/3, 0.4, 0.45). Upon cooling down from high temperature, a slight softening in V and dramatic stiffening are observed in all samples, and this stiffening is coincided with a big attenuation peak. The relative increase of V is proportional to the Sr concentration, which implies that this anomaly is strongly correlated with Fe4+. However, no obvious changes in magnetic and electric properties are found at this temperature range. The analysis suggests that this feature may be caused by the Jahn–Teller effect of Fe4+ and correspond to the formation of short-range charge-ordering state.