Morphology and Electron Spin Resonance of the (La1-xSnx)(2)Mn2O7 Double Perovskite System

作者：Husain Shahid^*; Bhat Irshad Ahmad; Khan Wasi; Alkhataby Lila; Cicek Ekrem

来源：Chinese Journal of Physics, 2013, 51(3): 551-559.

DOI：10.6122/CJP.51.551

We have synthesized (La1-xSnx)(2)Mn2O7 (x = 0.1, 0.15, and 0.25) samples using the solid state reaction (SSR) technique and the chemical reaction route (CRR). The powder X-ray diffraction (XRD) patterns show that all samples are in a single phase. The particle size distribution of the as prepared samples has been measured using scanning electron microscopy (SEM). Electron spin resonance (ESR) has proved to be useful for studying the spin dynamics of the Mn ion interaction mechanism and the dynamical Jahn-Teller distortions in perovskite manganites. We have recorded the ESR spectra at different temperatures in order to investigate the internal dynamical properties of the (La1-xSnx)(2)Mn2O7 system. We have observed that the intensity of the ESR line decreases exponentially with the temperature. The activation energy is calculated using the expression I(T) = I-0 exp(E-a/k(B)T). In the high temperature region, 1/I(T) follows the Curie-Weiss law. The ESR line-width with respect to temperature, Delta H(T), for the samples was fitted to the one phonon process, Delta H(T) = A + BT, where A is constant and B is a parameter related to lattice distortions. The value of the parameter B decreases in both cases with an increase in Sn concentration, indicating a decrease in the lattice distortion.

• 出版日期2013-6