Diffusion of Strontium in the Intergranular Boundaries of La2- xSrxCuO4

Bykov, A. A.; Gokhfeld, D. M.; Terent'ev, K. Yu; Volochaev, M. N.; Petrov, M., I Russian Journal Of Physical Chemistry A. https://doi.org/10.1134/S0036024421060066

Energy dispersive X-ray spectroscopy and scanning electron microscopy are used to study La2CuO4–La1.56Sr0.44CuO4 composites with different annealing times. Maps of the strontium distribution for such systems are calculated and compared to experimental data obtained for the area of contact between two dissimilar granules. The coefficient of lattice diffusion of strontium is found. At the areas of contact between La2CuO4 and La1.56Sr0.44CuO4 granules, the strontium concentration corresponds to superconducting phase La2−xSrxCuO4 with x = 0.05–0.25. The technological parameters of synthesis affect the size and number of superconducting and normal regions. Prolonged annealing lowers the gradient of the strontium concentration, which halts the increase in the size of the superconducting regions. This saturation confirms the diffusion front model.