Ultrasonic study on charge ordering in Nd0.5Ca0.5Mn1-xAlxO3 (x=0,0.03)

作者：Liu, Yi; Kong, Hui; Su, Jin-rui; Zhu, Chang-fei^*

来源：Chinese Journal of Chemical Physics, 2006, 19(6): 535-538.

DOI：10.1360/cjcp2006.19(6).535.4

• manganite
• charge ordering
• phase separation
• ultrasonic velocity and attenuation

The ultrasonic, magnetic and transport properties of Nd0.5Ca0.5Mn1-xAlxO3 (x=0, 0.03) were studied from 15 to 300 K. The temperature dependencies of resistivity and magnetization show that Nd0.5Ca0.5MnO3 undergoes a charge ordering transition at T-CO similar to 257 K. An obvious softening of the longitudinal sound velocity above T-CO and a dramatic stiffening below T-CO accompanied by an attenuation peak were observed. These features imply a strong electron-phonon interaction via the Jahn-Teller effect in the sample. Another broad attenuation peak was observed at around T-p similar to 80 K. This anomaly is attributed to the phase separation between the antiferromagnetic (AFM) and paramagnetic (PM) phases and gives a direct evidence for spin-phonon coupling in the compound. For the x=0.03 sample, both the minimum of sound velocity and attenuation peaks shift to a lower temperature. The results indicate that the charge ordering and CE-type AFM state in Nd0.5Ca0.5MnO3 are both partially suppressed by replacing Mn with Al.

• 出版日期2006-12-27
• 单位中国科学技术大学