Influence of La concentration on structural, morphological, optical and magnetic properties of Sr1-x LaxTiO3 nanopowders

Highlights: • Morphology and size of La-doped SrTiO3 are influenced by La doping. • Optical gap increased from 3.206 to 3.413 eV with increasing La content. • Weak paramagnetic behavior was observed in samples of low La content. • Paramagnetic behavior was observed in samples of high La content. • Ti3+ O2- Ti3+ coupling was suggested for the magnetic behavior. -- Abstract: Sr_1-x La_xTiO₃ (x = 0–0.50) nanopowders were synthesized by hydrothermal method. XRD results revealed a cubic perovskite structure of all samples. Second phase of La(OH)₃ was found in samples of x = 0.30–0.50 with LaTiO₃ in that of x = 0.50. SEM and TEM images of all products displayed nanoparticles of a cubic shape with addition of needle shape for samples of x = 0.30–0.50. EDX results indicated the existence of Sr, La, Ti and O in the samples. XANES results confirmed the presence of Ti³⁺ and Ti⁴⁺ cations in La-doped SrTiO₃ structure. Optical band gaps of Sr_1-x La_xTiO₃ nanopowders increased from 3.206 to 3.413 eV with increasing La concentration. VSM results revealed diamagnetic, weak paramagnetic and paramagnetic behaviors for SrTiO₃, samples of x = 0.10 and 0.20, and samples of x = 0.30–0.50, respectively.