Spin dynamics in ⁵⁷Fe‐doped TiO₂ anatase nanoparticles

Abstract

Abstract In this paper we present electron paramagnetic resonance (EPR) and Mössbauer (transmission method, TMS and measurements in the scattering method, CEMS) experiments on 57 Fe (0.1–1 at.%) doped nanocrystalline anatase‐type TiO 2 , synthesized by a hydrothermal method. Different Fe 3+ and Fe 2+ ions positions, with various hyperfine interactions evidenced in Mössbauer spectra (MS), confirm a partial magnetic ordering at room temperature. The magnetic hyperfine fields in the TMS spectra, better resolved at lower temperatures, do not change essentially with temperature. The first CEMS measurements, carried out on iron‐doped TiO 2 nanoparticles, reveal a larger disorder in the surface particles layer. The temperature dependence of the double integral EPR spectral intensity, proportional with the sample susceptibility, shows an anomalous behaviour. It suggests the bound magnetic polaron (BMP) mechanism for the magnetic ordering.