Ultrasonic study on the Jahn-Teller effect near different phase transitions in La1/3Sr2/3MO3 (M=Mn, Fe, Co)

作者：Kong Hui; Zhu Changfei

来源：Solid State Communications, 2012, 152(18): 1715-1718.

DOI：10.1016/j.ssc.2012.07.003

• Transition metal alloys and compounds
• Electron-phonon interaction
• Ultrasonic

The longitudinal ultrasonic velocity (V-I), magnetization and resistivity of polycrystalline La1/3Sr2/3MO3 (M=Mn, Fe, Co) have been measured between 20 and 300 K. Dramatic anomalies in VI were observed near the temperature of the charge-ordering transition (CO), charge disproportionation transition (CD), and ferromagnetic transition (FM), which are explained by the Jahn-Teller effect originating from the M ions (M=Mn, Fe, Co). However, the detailed form of these anomalies is different, which is strongly depended on the M ion's unique electronic structure. For La1/3Sr2/3MO3 (M=Mn, Fe), the 1/1 exhibits a valley around the CO transition temperature because of the localization of the Jahn-Teller active ions (Mn3+, Fe4+). And due to the instability of Fe4+, the CD transition occurs in La1/3Sr2/3MO3, which results in another softening in VI, while only normal increase is observed in La1/3Sr2/3MO3. For La1/3Sr2/3CoO3, the local lattice distortion via the Jahn-Teller effect of intermediate spin Co3+ leads to the velocity anomaly in the ferromagnetic metallic state.

• 出版日期2012-9
• 单位安徽工业大学