Room temperature ferromagnetism in Cu2+ doped TiO2 nanocrystals: The impact of their size, shape and dopant concentration

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

“…The lowering in band gap energy for doped samples strongly indicates Cu cations have been successfully incorporated into the TiO 2 crystal lattice. The decrease of band gap with Cu doping is in agreement with the earlier works on Cu doping in TiO 2 and other forms of TiO 2 doped with Fe or Cr . In comparison to the undoped TiO 2 nanopowders, the E g values for x = 0.02 (TC2), 0.04 (TC4), and 0.06 (TC6) were found to decrease with Cu doping.…”

“…The 2.37 eV emission correlated with singly ionized V O , generally found in TiO 2 nanoparticles. Singly occupied V O (V O with one electron) with a spin of 1/2 has been previously ascribed to the origin of RTFM in TiO 2 powders and nanoparticles , and TiO 2 :Cu thin films , nanorods , nanocrystals , and nanoparticles . Note that the PL intensity of the Cu‐doped TiO 2 samples was much higher than that of dopant‐free TiO 2 , demonstrating that Cu ions replaced the Ti site in TiO 2 , confirming that the obtained FM signals presented below were from Cu replacement but not from impurities and that Cu doping can enhance the reintegration of photo‐created electrons and holes.…”

“…Due to its nonferromagnetic properties, the second phase perturbs the presence of magnetic ordering structure in the samples . The M s value per Cu atom exceeded the previously reported values of 10 −3 emu g −1 and ∼10 −2 μ B Cu −1 for Cu‐doped anatase TiO 2 nanorods and anatase Ti 1‐x Cu x O 2 nanoparticles (x = 1.03) , respectively. But it was smaller than the M s observed for Cu‐doped rutile TiO 2 thin films and Cu‐doped TiO 2−δ films , and comparable to those obtained for Cu‐doped TiO 2 nanorods .…”

Shaped Co2+ doped TiO2 nanocrystals synthesized from nanotubular precursor: Structure and ferromagnetic behavior

“…More precisely, the problem of so called "self-purifications", according to which the dopant ions are expelled from the nanoparticle core during the crystal growth when synthesis starts from the molecular precursors [19], should be prevailed. We developed hydrothermal synthetic procedure for incorporation of various dopant ions (transition metal ions and rare earth ions) in TiO 2 nanocrystals of various shapes (faceted nanoparticles, prolate nanospheroids) using dispersions of titania nanotubes and dopant ions, as precursors [20][21][22][23]. In our previous work, we reported ferromagnetic ordering in faceted Co 2+ doped TiO 2 nanoparticles synthesized hydrothermally in acidic conditions (pH = 3), by shape transformation of titania nanotubes in the presence of Co 2+ ions [24].…”

Cтруктурные И Магнитно-Люминесцентные Свойства Допированного Углеродом Оксида Алюминия

“…чи-стых и допированных немагнитными элементами окис-лов HfO 2 [1][2][3], TiO 2 [4,5], ZrO 2 [6][7][8][9][10], ZnO [11][12][13], SiO 2 [14][15][16] привлекают большое внимание из-за их потенциального применения в устройствах спинтроники. Авторы [17,18] сообщали об обнаружении ферромагне-тизма при комнатной температуре (ФМКТ) в наноча-стицах отдельных оксидов, в частности оксида Al 2 O 3 .…”