  The charge ordering (CO) transition in polycrystalline La1/3Sr2/3MnO3 has
been studied by measuring the resistivity, magnetization and transverse
ultrasonic velocity. At about 235K, a conspicuous increase in resistivity was
observed, while the magnetization shows a cusp structure, corresponding to an
antiferromagnetic charge ordering transition. Around this transition
temperature, dramatic anomaly in transverse sound velocity was observed. The
simultaneous occurrence of electron, magnon and phonon anomalous features
implies strong spin-phonon coupling and electron-phonon in La1/3Sr2/3MnO3. The
analysis suggests that the spin-phonon interaction is due to single-ion
magnetostriction, and electron-phonon coupling originates from the Jahn-Teller
effect of Mn3+.
