Ultrasonic and elastic moduli evidence for Curie temperature (Tc) in Sm1−xSrxMnO3 perovskite magnetic materials at x = 0.25, 0.30, 0.37, 0.40 and 0.44

Sm1−xSrxMnO3 perovskite manganite materials with different compositions (x = 0.25, 0.30, 0.37, 0.40 and 0.44) have been prepared using solid state reaction technique. On-line ultrasonic velocities and attenuation have been measured over a wide range of temperatures from 120 to 298 K employing through transmission method operated at a fundamental frequency of 5 MHz. In all compositions, Curie temperature (Tc) and Jahn-Teller temperature (TJT) have been discussed in light of observed interesting results on temperature dependence of ultrasonic parameters. Phase transition from ferromagnetic to canted ferromagnetic state has been observed at Tc. The increase in the magnitude of maximum velocities with change in Sr content at Tc indicates the strength of linear magnetostriction effect. The observed results reveal that Tc value decreases with an increase in Sr content. The existence of Jahn-Teller transition due to electron-phonon interaction and large lattice distortion which is due to the double exchange interactions have been demonstrated from the observed ultrasonic parameters as a function of temperature.