Magnetic Aftereffects in Titanium Ferrites

Abstract

Magnetic aftereffect (MAE) measurements in TixFe3—x—ΔO4 with 0.01 ≤ x ≤ 0.4 (Δ ≈︂ 10—4) are performed by means of an oscillator technique in the temperature range 4 K < T < 460 K. The specific electronic MAE processes below the Verwey temperature, i.e., tunnelling (4 K <T < 35 K) and long-range hopping (50 K < T < 125 K), are found to be severely affected in the presence of even small Ti contents (0.01 ≤ x ≤ 0.1). Above the Verwey temperature four main processes are detected around 215 K (IV′), 260 K (IV), 300 K (III) and 415 K (II). Atomistic models, based on the vacancy model for process III in magnetite, are proposed in order to explain the observed spectra.