Sound Velocity Anomaly Associated with Polaron Ordering in La_{<b>1-<i><i>X</i></i></b>}Sr_{<i><i>X</i></i>}MnO_<b>3</b>

Abstract

The sound velocity v s ( T ) and the electrical resistivity ρ( T ) of La 1- X Sr X MnO 3 (0.11≤ X ≤0.17) have been measured and anomalies in v s ( T ), which are related to the polaron-ordered phase centered at X =1/8, have been observed. The phase diagram between the polaron-ordering temperature T P and X has been determined from the v s anomalies.