Elastic behaviour of strontium-doped lanthanum calcium manganites in the vicinity of TC Original Research Article

Colossal magnetoresistance (CMR) manganites with compositional formula, La0.67Ca0.33−x Srx MnO3 (where x =0, 0.09, 0.11, 0.13, 0.33) were prepared by citrate gel route mainly to understand the elastic behaviour in the vicinity of their magnetic transition temperature T C. The structural characterizations of all the materials clearly indicate that samples upto x =0.13 doping, are having orthorhombic structure with Pbnm space group and sample with x =0.33 is having rhombohedral structure with View the MathML sourceR3¯c space group. The magnetic transition temperatures (TC) are determined by AC susceptibility measurements and are found to increase continuously with increasing strontium concentration. Finally, a systematic investigation of the ultrasonic longitudinal velocities of all the samples was carried out. Further, all the samples are found to exhibit anomalous behaviour in the vicinity of their magnetic transition temperatures and the observed behaviour is explained using Landauʹs theory.