Anomalies of ultrasonic velocities, attenuation and elastic moduli in Nd1−xSrxMnO3 perovskite manganite materials

Nd1−xSrxMnO3 perovskite manganite material with different compositions (x=0.31, 0.35, 0.37, 0.39 and 0.41) have been prepared employing solid-state reaction technique. The ultrasonic velocities and attenuation of the above samples have been measured employing through transmission method operated at a fundamental frequency of 5 MHz over wide range of temperatures. The temperature dependence of ultrasonic velocities, attenuation, relative percentage variation in velocities and elastic constants show an interesting anomaly in all compositions. The observed anomalies in ultrasonic parameters at Tc in all compositions have been revealed in terms of existence of ferromagnetic (FM) state. Similarly, the anomalies at Tco show the transition from FM to charge-ordered antiferromagnetic (AFM) state. The observed results have been used to explore the competitions between FM and AFM.