## 3 Results  
### Structure and Morphology  
The La\({}_{0.9}\)A\({}_{0.1}\)Mn\({}_{0.9}\)Co\({}_{0.1}\)O\({}_{3}\) powders and ceramics were characterized by X-ray diffraction at room temperature (Figure 1). The crystal structure and the unit cell parameters were calculated using the Rietveld refinement with the X'pert HighScore Plus software using the pseudo-Voigt profile shape function, the background profile was fitted by the Lagrangian polynomial of 5 th order [27]. This procedure allowed to attest the phase purity of the compounds and also to determine the crystal structure and structural parameters. The analysis of the XRD results indicated the rhombohedral symmetry described by _R-3c_ space group (ICSD 75070) [28], which are similar to the structural results obtained for the La\({}_{0.9}\)A\({}_{0.1}\)MnO\({}_{3}\) compounds, previously studied by the authors [24], and other LaMnO\({}_{3}\)-based compounds [29]. It should be noted that the crystal structure of undoped compounds is also characterized by the rhombohedral distortion of the unit cell which implies nominal oxygen excess in LaMnO\({}_{3+\delta}\) (\(\delta\) \(>\) 1%) compounds [30], leading to nonzero remanent magnetization as compared to stoichiometric LaMnO\({}_{3}\) having an orthorhombic structure [31]. After the application of pressure, the diffraction peaks became wider, which may indicate a decrease in grain size associated with the decomposition of particle shells from the crystalline to amorphous state, such a phenomenon has already been described in our previous study [32]. In addition, the broadening of reflections is associated with the introduction of additional strains into the structure induced by high pressure during the sintering process [33]. It should be noted that the introduction of the bigger ion and the pressure applied during sintering lead to an increase in the strain in the compounds. It was observed that the introduction of 10 mol.% of alkali ions does not change the structure but clearly shifts the peaks to the higher 20 degrees and increases the ionic radii [34]. This suggests an expansion of the unit cells and an increase in their volumes (Table 1) as confirmed by the results of the Rietveld refinement analysis. It should be noted that no additional peaks coming from the secondary phase were observed for the initial powder compounds, while the XRD patterns of the ceramic compounds contain distinct extra reflection located at \(\sim\)26.5 20 deg. The observed reflection is attributed to h-BN material integrated into tablets during the pressure procedure, which does not affect the crystal structure and the magnetic properties. In the case of ceramics, the applied pressure leads to a decrease in the unit cell volume, which has a significant impact on the magnetic properties of the ceramics as compared to the starting powders [35]. As the XRD measurements were performed in the reflection mode, the ceramics are small and, in some cases, they do not have parallel surfaces, the XRD patterns at high 2\(\Theta\) degrees become noisy and the baseline rises. However, the main peak observed at lower degrees shows that the structure of the ceramics remains unchanged and is described by the rhombohedral symmetry. Figure 1: XRD patterns recorded for La\({}_{0.9}\)A\({}_{0.1}\)Mn\({}_{0.9}\)Co\({}_{0.1}\)O\({}_{3}\) powders and ceramics (**a**). The right panel shows enlarged region of the pattern, with shift of the peak and with change of the dopant ionic radius observed in powders (**b**) and broadening of the peak observed for ceramics (**c**). The SEM images show that the combustion synthesis significantly affects grain morphology (Figure 2). Short synthesis time allows one to obtain nanosized crystallites and later calcination leads to their agglomeration. The high temperature generated during self-combustion (above 1500 \({}^{\circ}\)C) and relatively short calcination time causes broad grain size distribution and the crystallization of bigger grains [36].