Ferromagnetic properties and conversion-electron Mossbauer spectroscopy of (La2O3)x–(Bi2O3)1−x–Fe2O3 films

(La2O3)x–(Bi2O3)1−x–Fe2O3 films were synthesized by the sol–gel technique on Si (100) substrates. The crystal structure of the samples was studied by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The magnetic properties were studied by vibrating sample magnetometry and conversion-electron Mossbauer spectroscopy (CEMS). The samples were amorphous or nanocrystallized in structure and had ferromagnetic properties with clear enhancement of saturation magnetization when La concentration was increased. The CEMS measurement revealed two doublets in the spectra. The central shift and quadrupole splitting of the doublets were increased with increasing La concentration. This is attributed to the decreasing of s-electron density in the iron nucleus and asymmetry of the electrical field around the nucleus enhanced by La doping. ►(La2O3)x–(Bi2O3)1−x–Fe2O3 thin films were synthesized by sol–gel. ► Ferromagnetism enhanced with La doping. ► CEMS study of the hyperfine structure of the films carried out.