Magnetocaloric effect and critical exponent analysis in electron-doped La1−xTexMnO3 compounds: a comprehensive study

Abstract

The synthesis of electron-doped perovskite manganite system La1−xTexMnO3 where x = 0.05, 0.10, 0.15 and 0.20 along with its structural, magnetic properties and magnetocaloric effect has been studied in this article. A single phase rhombohedral structure in space group is identified for all the samples. The structural model revealed from the Rietveld analysis indicates the presence of distortion in the MnO6 octahedron. XAFs studies indicated the electron-doping behavior with strong hybridization between Mn and O. Second-order paramagnetic (PM) to ferromagnetic (FM) transitions is observed in all the samples from the Arrott’s plot and its critical exponent theory. The magnetic transition and the double exchange mechanism can be well explained by the long-range mean-field theory. The PM-to-FM transition temperature (Tc) enhances slightly as a function of ‘Te’ contents up to 15% and again it decreases for 20%. The theoretical change in entropy determined from the Gibbs free energy nearly matches with the experimentally calculated change in entropy. The maximum calculated experimental change in entropy and relative cooling power for Te15 sample at 5 T is 2.94 J kg−1 K−1 and 125.65 J kg−1, respectively, and the values are comparable with the literature values.