Electron spin resonance investigation of the substitution of Fe ³⁺ for Ti ⁴⁺ ions in rutile TiO ₂ single crystal

Abstract

A Fe doped rutile TiO 2 single crystal is grown in an O 2 atmosphere by the floating zone technique. Electron spin resonance (ESR) spectra clearly demonstrate that Fe 3+ ions are substituted for the Ti 4+ ions in the rutile TiO 2 matrix. Magnetization measurements reveal that the Fe:TiO 2 crystal shows paramagnetic behaviour in a temperature range from 5 K to 350 K. The Fe 3+ ions possess weak magnetic anisotropy with an easy axis along the c axis. The annealed Fe:TiO 2 crystal shows spin-glass-like behaviours due to the aggregation of the ferromagnetic clusters.