Magnetic phenomena in multi-phase In–Sn–O nanoparticles

Composite nanoparticles of tin-indium oxide mixtures based on In–Sn alloys (90:10) and (50:50) with an average particle size of 40–310 nm were obtained through the levitation-jet method by condensing alloy vapor in a gas flow of helium and air. The nanoparticles were studied using scanning electron microscopy, X-ray diffraction analysis, BET method, and vibrating sample magnetometry. It was found that the synthesized nanoparticles are a complex mixture that includes several crystallographic phases: metallic indium, In0.2Sn0.8 alloy, simple oxides In2O3, SnO, and SnO2, as well as complex mixed oxides (In1.88Sn0.12)O3 and In4Sn3O12. For the first time, in these nanoparticles, ferromagnetism with magnetization achieving a maximum of 0.01 emu/g in a magnetic field 10 kOe and superconductivity with diamagnetic susceptibility approx. − 1 × 10−6 cm3/g at room temperature were discovered. The coexistence of ferromagnetic ordering and superconductivity is associated with the presence of different localized states on defective interfaces between different crystalline phases because of magnetic field-induced temporal clustering of these states as a result of their exchange interaction. © 2025 Elsevier B.V., All rights reserved.