Title :
Ultrasonic investigation of charge-ordering compound La0.5 Ca0.5MnO3 under magnetic field
Author :
Zhu, C.F. ; Zheng, R.K. ; Xie, J.Q.
Author_Institution :
Dept. of Mater. Sci. & Eng., Univ. of Sci. & Technol. of China, Hefei, China
Abstract :
The longitudinal ultrasonic sound velocity and attenuation of single-phase polycrystalline compound La0.5Ca0.5MnO3 have been measured by a conventional pulse-echo-overlap technique at a frequency of 10 MHz, between 77 K and 270 K. The effects of magnetic field on ultrasonic properties are also investigated. A dramatic stiffening in sound velocity coincided with big attenuation peaks observed near the charge-ordering transition temperature. Under an external magnetic field, the stiffening of the sound velocity shifts to lower temperature, and the attenuation peak was dramatically suppressed. This feature implies extremely strong spin-phonon and electron-phonon coupling originating in the Jahn-Teller effect
Keywords :
Jahn-Teller effect; antiferromagnetic materials; calcium compounds; charge-ordered states; electron-phonon interactions; ferromagnetic materials; ferromagnetic-antiferromagnetic transitions; lanthanum compounds; magnetoacoustic effects; magnetoresistance; solid-state phase transformations; spin-phonon interactions; ultrasonic absorption; ultrasonic velocity; 10 MHz; 77 to 270 K; Jahn-Teller effect; La0.5Ca0.5MnO3; attenuation peak suppression; attenuation peaks; charge-ordering La0.5Ca0.5MnO3 compound; charge-ordering transition temperature; electron-phonon coupling; external magnetic field; longitudinal ultrasonic sound attenuation; longitudinal ultrasonic sound velocity; magnetic field; pulse-echo-overlap technique; single-phase polycrystalline La0.5Ca0.5MnO 3 compound; sound velocity stiffening; sound velocity stiffening shift; spin-phonon coupling; ultrasonic investigation; ultrasonic properties; Antiferromagnetic materials; Attenuation measurement; Frequency; Lattices; Magnetic field measurement; Magnetic properties; Pulse measurements; Solids; Temperature; Ultrasonic variables measurement;
Conference_Titel :
Electron Devices Meeting, 2001. Proceedings. 2001 IEEE Hong Kong
Conference_Location :
Hong Kong
Print_ISBN :
0-7803-6714-6
DOI :
10.1109/HKEDM.2001.946933
