Effect of annealing ambient on the ferromagnetism of Mn-doped anatase TiO₂films

Abstract

The magnetic properties of anatase Ti1−xMnxO2 (0 < x < 0.06) films prepared by sol–gel spin coating annealed in air and vacuum have been investigated. Room temperature ferromagnetism was observed in all the films. Enhancement of ferromagnetism is revealed in the films annealed in vacuum. The magnetic moment of the films annealed in vacuum, at 300 K, is 0.285 ± 0.004 μB/Mn for Ti0.9618Mn0.0382 O2 and 0.366 ± 0.005 μB/Mn for Ti0.9409 Mn0.0591O2. It is believed that the enhanced ferromagnetism could be due to the formation of oxygen vacancies and/or defects.

Structural, optical, and magnetic properties of Cu‐doped TiO2 samples

“…The expansion of the lattice is consistent with the fact that the ionic radius of Cu 2+ is 0.73 Å, whereas that of Ti 4+ is 0.61 Å; both ionic radii are in six‐fold coordination . Substitution of Cu 2+ for Ti 4+ is expected to add V O for local charge neutrality , and these together can lead to such a lattice parameter change . Furthermore, the cell parameters of the TiO 2 :0.02Cu samples annealed at higher temperatures of 600 and 700°C (TC2‐600 and RTC2‐700) were higher than those of the TiO 2 :0.02Cu samples annealed at 500°C.…”

Ferromagnetism of Mn-doped TiO2 nanorods synthesized by hydrothermal method

“…The effect of such ferromagnetic clusters must be examined more carefully before the usefulness of such materials for spintronics applications can be determined [15]. In this context, recent reports [16][17][18][19] about the observation of RTFM in manganese doped TiO 2 has been taken with great enthusiasm by the scientific community. This is mostly because of the fact that the metallic manganese, as well as all possible Mn-O based secondary phases (except Mn 3 O 4 with T C ∼ 43 K), are nonferromagnetic.…”

Synthesis of manganese oxide supported on mesoporous titanium oxide: Influence of the block copolymer

“…1a). Such a shift had already been seen in the case of the Mn-Ti-O system and attributed to the substitution of Mn 4 þ (ionic radius 0.67 Å) for Ti 4 þ (ionic radius 0.68 Å) [49][50]. Furthermore, the (1 0 5) and (2 1 1) reflections initially observed at 53.91 and 55.01, respectively, merged.…”

“…However, among the studies devoted to the elaboration of binary Mn-Ti oxides [44][45][46][47][48][49][50], very few reported the use of the self-assembly method [44]. Solid solutions of Mn in anatase were often reported [49][50][51][52], but binary oxides such as Mn 2 TiO 4 and MnTiO 3 were also observed at high temperature [51][52][53]. For such bimetallic systems, the relative localization of the two components is always a matter of discussion.…”