Synthesis and on-line ultrasonic characterisation of bulk and nanocrystalline La0.68Sr0.32MnO3 perovskite manganite

Synthesis and characterization of La1-xSr xMnO3±δ powders obtained by the polymeric precursor route

“…These latter applications are due to the outstanding magnetotransport properties of these oxides [7][8][9] . In the LSM perovskite structure, Mn 3+ or Mn 4+ ions are the network formers, occupying the octahedral B sites and are associated to the oxygen reduction, whilst the ion La 3+ , partially replaced in the twelve-fold oxygen coordinated sites A, are related to the property of electronic conduction.…”

Facile synthesis and characterisation of La0.55Pb0.45MnO3nanoperovskites employing ultrasonic measurements

“…Generally, a decrease in velocity and an increase in attenuation are due to lattice softening, whereas an increase in velocity and decrease in attenuation are mainly due to lattice hardening as reported by Sankarrajan et al [25]. An abrupt change in strong coupling between spin, charge, orbital, and lattice degrees of freedom and interactions at transition temperature are responsible for the observed anomaly in ultrasonic velocities and attenuations [36]. Therefore, the observed anomalous ultrasonic parameter is not only correlated with phase transition temperature (T c ), but is also with strong electron-lattice interaction via Jahn-Teller distortion of Mn 3+ O 6 and spontaneous spin ordering below T c .…”

“…Few attempts have been made to compare the T c values by changing the various grain size using ultrasonic studies, even though the characterisation of LPMO nanoperovskites through ultrasonic non-destructive testing [23][24][25] is a novel and promising technique to examine the structural and phase transitions and correlate the differences between FM and PM phase physical properties [26]. The interactions of ultrasonic waves and the coupling in perovskite manganite materials between the structural, spin orbital and strain lead to corresponding changes in lattice.…”

Effect of rare earth ions on transition temperature in perovskite materials by on-line ultrasonic studies

“…The maxima/minima α L as a function of perovskites and their composition are shown in Figure 4. The T c in all perovskites that is observed shows the existence of competition among the PM, FM and AFM phases 21,24,26 . The values of ionic radii for rare earth elements, La, Pr, Nd and Sm, are 1.172, 1.13, 1.123 and 1.098 Å respectively.…”

“…Even though, different techniques are known in exist to explore structural/phase transition temperatures in perovskites manganite materials, on-line ultrasonic measurement is important tool due to their precise on-line evaluation of structural/phase transitions, non-destructive method of measurement, accurate and reproducibility of results than any other experimental methods 21 . It is inferred from the literature that no attempts have been made to compare the T c using ultrasonic studies by changing the R and x values.…”