## 3 Results and Discussion
### Conductivity
#### 3.3.2 Temperature Dependencies of Conductivity  
Dry Conditions  
The temperature dependencies of conductivities of the newly synthesized compound La\({}_{2}\)ScZnO\({}_{5.5}\) compared with those of La\({}_{2}\)AlZnO\({}_{5.5}\)[46] and La\({}_{2}\)InZnO\({}_{5.5}\)[47] are shown in Figure 6.  
As can be seen, the values of total conductivities are close to each other, although the In\({}^{3+}\)-containing sample showed the highest conductivity; for the temperatures T \(<\) 500 \({}^{\circ}\)C, the electrical conductivity increases in the sequence La\({}_{2}\)AlZnO\({}_{5.5}\)\(<\) La\({}_{2}\)ScZnO\({}_{5.5}\)\(<\) La\({}_{2}\)InZnO\({}_{5.5}\), and at high temperatures, the Sc sample had a conductivity by 0.3 orders of magnitude lower. All of these samples have the same number of oxygen ions and consequently oxygen deficiency (all elements are present in the highest stable oxidation states). Therefore, the changes in the conductivity may be due to the changes in the mobility of oxygen ions or due to the changes in electronic contribution. For understanding the phenomenon, studies on ionic transport numbers are needed, but in principle, the nature of the B-cation does not significantly affect the total conductivity. The comparison of the temperature dependencies of conductivities of undoped phase La\({}_{2}\)ScZnO\({}_{5.5}\) and Ca\({}^{2+}\), Mg\({}^{2+}\)-doped phases is shown in Figure 7. It is clearly seen that doping increases conductivity. The increase in conductivity can be associated with an increase in the concentration of oxygen vacancies due to acceptor doping. However, doped samples are characterized by an equal level of oxygen deficiency, but the conductivities of these phases are significantly different. That is, the oxygen mobility in the doped phases is significantly different. Figure 6: Temperature dependencies of the conductivities of La\({}_{2}\)ScZnO\({}_{5.5}\), La\({}_{2}\)AlZnO\({}_{5.5}\)[46], and La\({}_{2}\)InZnO\({}_{5.5}\)[47]. the incorporation of water and the formation of proton current carriers below 500\(-\)550 \({}^{\circ}\)C. At high temperatures (T > 600 \({}^{\circ}\)C), water is removed (according to the TG data) and the conductivities in dry and wet atmospheres are comparable. Thus, the investigated phases are capable of exhibiting proton conductivity. A comparison of the conductivity in wet air shows similar trends as for dry air; it increases in the sequence: La\({}_{2}\)Sc\({}_{0.9}\)Mg\({}_{0.1}\)ZnO\({}_{5.45}\) < La\({}_{1.9}\)Ca\({}_{0.1}\)ScZnO\({}_{5.45}\) < La\({}_{2}\)Sc\({}_{0.9}\)Ca\({}_{0.1}\)ZnO\({}_{5.45}\). Figure 9 shows that conductivity increases with an increase in the lattice-free volume. Since the concentration of protons is approximately equal (according to the TG data), an increase in proton conductivity is associated with an increase in the mobility of protons. This trend, shown in Figure 9, reflects the fundamental  
Figure 8: Comparison of the conductivities and activation energies as a function of the free lattice volume for high-temperature region (T > 700 \({}^{\circ}\)C) in dry air for the samples: La\({}_{2}\)ScZnO\({}_{5.5}\) (LSZ), La\({}_{2}\)Sc\({}_{0.9}\)Mg\({}_{0.1}\)ZnO\({}_{5.45}\) (LZSMg), La\({}_{2}\)Sc\({}_{0.9}\)Ca\({}_{0.1}\)ZnO\({}_{5.45}\) (LZSCA), and La\({}_{1.9}\)Ca\({}_{0.1}\)ScZnO\({}_{5.45}\) (LCaZS). Figure 9: Comparison of the conductivities and activation energies as a function of the free lattice volume for the low-temperature (T < 500 \({}^{\circ}\)C) region in wet air for the samples: La\({}_{2}\)ScZnO\({}_{5.5}\) (LSZ), La\({}_{2}\)Sc\({}_{0.9}\)Mg\({}_{0.1}\)ZnO\({}_{5.45}\) (LZSMg), La\({}_{2}\)Sc\({}_{0.9}\)Ca\({}_{0.1}\)ZnO\({}_{5.45}\) (LZSCA), and La\({}_{1.9}\)Ca\({}_{0.1}\)ScZnO\({}_{5.45}\) (LCaZS). dynamics of oxygen sublattice and proton mobility [60]. There are many examples in the literature to support this assumption. For example, [PERSON] et al.