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本文研究了La1/3Sr2/3Fe0.985Mn0.015O3单相多晶样品在低温下的电荷输运性质和超声特性。电阻测量结果表明,样品在190K处发生了电荷有序相变。而超声声速从室温开始就出现了明显的软化,在电荷有序温度(T CO)附近达到最小值,随后又急剧硬化,同时伴随着一个衰减峰。分析指出这是由于电-声子相互作用导致的结果,该电-声子耦合起源于Fe4+的Jahn-Teller效应。电荷有序温度之下超声声速出现了新的软化,该现象起源于Fe4+和Fe5+由于离子半径不同导致的呼吸模式的晶格扭曲。
In this paper, charge transport properties and ultrasonic properties of La1 / 3Sr2 / 3Fe0.985Mn0.015O3 single-phase polycrystalline samples at low temperature were studied. The result of resistance measurement shows that charge-order phase transition occurs at 190K. The supersonic velocity of sound appears to soften significantly from room temperature, reaching a minimum near the charge-ordering temperature (T CO) and then abruptly hardens with a decay peak. The analysis indicates that this is due to the electro-phonon interaction that results from the Jahn-Teller effect of Fe4 +. A new softening of the supersonic velocity at a charge-order temperature has been attributed to the lattice distortion of the respiratory modes due to the difference in ion radii between Fe4 + and Fe5 +.