Revealing the Impact of Ga and Y Doping on Thermal and Electrical Behavior of LaMnO 3 Ceramic Materials.

The synthesis, thermal behavior and electrical properties of a series of undoped and 1% Ga- or Y-doped lanthanum manganite compounds, obtained via the sol–gel technique, are reported. Scanning electron microscopy (SEM/EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analyses were performed on all synthesized samples. The XRD results confirmed a good crystallinity for all studied samples, and a change in the crystal structure of Ga- or Y-doped lanthanum manganite (Pm-3m space group) was observed compared to the pristine sample (R-3c space group). Thermal analysis highlighted a different behavior of the doped samples compared to the undoped sample, observed by the different mass losses in the analyzed temperature range. For these materials, it is shown for the first time that the static electrical conductivity, σ_DC, of Ga- or Y-doped LaMnO₃ compounds increases compared to the σ_DC of the pristine sample, and the thermal activation energy of the process of electrical conduction, E_A,cond, increases linearly with the temperature for all three studied samples. [ABSTRACT FROM AUTHOR]