Structure–property correlation in Fe-substituted La0.7Sr1.3Co1−xFexO4 Ruddlesden–Popper oxides: insights into nonlinear optical behavior

This study reports the influence of Fe substitution at the Co site on the structural evolution, linear optical behavior, and nonlinear optical properties of La 0.7 Sr 1.3 Co 1−x Fe x O 4 via modified sol-gel method. XRD analysis indicated an increase in the lattice parameters, specifically ‘a’ and ‘c’, as the Fe content rose. According to FESEM images, when the Fe content increases, the average particle diameter grows from roughly 60 nm for the undoped sample (x = 0) to about 210 nm for x = 0.5. The influence of Fe substitution at the Co site on obtained band gap values are decreasing from 3.60, 3.50, 3.38, to 3.35 eV for x = 0.0, 0.1, 0.3, and 0.5, respectively. The nonlinear optical properties are measured using the Z-scan method, which is a common technique for studying optical nonlinearity. The highest nonlinearity responses belong to sample x = 0.5 at 55 mW incident power of laser that causes n 2 and β are 9.57 × 10 − 8 cm 2 /W and 5.44 × 10 − 3 cm/W, respectively. The results show that increasing the Fe content leads to higher values of the nonlinearity responses. This material is a promising candidate for optical devices and optoelectronic applications.