Investigation of the nonlinear optical characteristics of the La0.7Sr0.3MnO3 nano-perovskite under (iron, cobalt, and nickel) substitution for manganese by Z-Scan technique and Wemple–DiDomenico model

Abstract

The investigation in this study focused on examining the nonlinear optical (NLO) properties of La_0.7Sr_0.3XO₃ (X= Mn, Co, Ni, or Fe) nano-perovskite powders utilizing the Z-scan technique. To achieve this objective, first, the samples were synthesized using the co-precipitation procedure, and after that, the prepared materials were examined using a field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD) to confirm the nanoscale morphology and structure of the prepared samples, respectively. Based on the FE-SEM and XRD outcomes, the nanosized nature of the materials has been verified. To analyze the NLO characteristics of the nanopowders, the Z-scan technique with a continuous wave 532 nm Nd: YAG laser was employed on laser incident powers of P₀ = 15 mW, and 30 mW. This is to determine the third-order nonlinear optical susceptibility, nonlinear refractive index (NLR, n₂), and nonlinear absorption coefficient (NLA, β) values. For La_0.7Sr_0.3MnO₃, the NLR and the NLA (precisely two phonon absorption) responses displayed at the 3.3339×10⁻⁹ m²/W and 0.0485 m/W values, respectively, measured for P₀ = 15 mW. It is evident from the results that after the Ni, Fe, or Co substitution for manganese in the La_0.7Sr_0.3MnO₃ measured for P₀ = 15 mW, the obtained results showed a decrement in the NLA response for all samples and a decrement in the NLR response for all samples except Co substitution. Moreover, to accurately ascertain linear susceptibility, dispersion energy, and the density of polarizable constituents from the acquired z-scan data, we employed Miller’s generalized rule as introduced by the Wemple–DiDomenico model and additionally utilized the relationship proposed by Fournier and Snitzer. The implications of the substitution process and the dimensions of the crystallites, along with their interrelation with nonlinear parameters, are thoroughly examined. The remarkable and encouraging nonlinear optical coefficients demonstrated by these synthesized nanopowders suggest their viability as significant materials for the fabrication of innovative optical devices.