Synthesis and characterization of Fe3O4:Yb3+:Er3+ nanoparticles with magnetic and optical properties for hyperthermia applications

Rare‐Earth Doped Iron Oxide Nanostructures for Cancer Theranostics: Magnetic Hyperthermia and Magnetic Resonance Imaging

“…[31,70,85] It has been observed that for doping with most of the major RE ions, namely Y 3+ , La 3+ , Dy 3+ , Eu 3+ , Nd 3+ , Sm 3+ , Tb 3+ , [31,70,71,77,84,85,94,99,100] a substantial increase in the particle size has been recorded, excepting a few cases. [76,79,105] For example, for Ce doped Fe 3 O 4 , we have categorically observed a decrease in the particle size after doping (Table 5), [76,79] an observation contrary to those reported with Gd and other major RE doped magnetite particles. The relatively large Ce 3+ ions (1.14 Å) lead to the expansion of lattice parameters (Table 5).…”

“…However, not many structural changes have been reported for RE doping with Y 3+ , Er 3+ , and Yb 3+ . Nearly spherical-shaped particles were still maintained after doping, [70,105] similar to that observed in RE doped binary and ternary rare-earth fluorides. [159] The change in the morphology of these magnetic nanostructures after doping is possibly due to the variation of the surface charge density on the different cations during the condensation process.…”

“…Similar observations have been reported in several such doped magnetite studies involving other RE ions. [70,71,77,79,80,82,85,100,105] However, due to the relatively large radius, the d-spacing could be expanded by doping. One such example is Y 3+ doping in Fe 3 O 4 , as shown in Figure 3B.…”

“…Impurities at substantially higher doping percentages were also reported for other RE doped magnetite systems. [80,105] Generally, no impurities could be observed at the doping concentration, suggesting all the dopants enter parent Fe 3 O 4 lattice sites. [32,42,80,98] Another interesting aspect of Gd doping is its effect on crystallite size, as it increases substantially with an increased doping concentration.…”

“…[35] Room temperature magnetic measurements have clearly shown this kind of identical behavior in terms of saturation magnetization for Gd doped other ferrite systems, namely CoFe 2 O 4 , synthesized by a hydrothermal procedure. As the Gd dopant concentration increased from x = 0 to x = 0.25, in CoFe 2-x Gd x O 4 , the magnitude of M S dropped by almost 30% [32] B) Gd 0.02 Fe 2.98 O 4 nanoparticles (less than 1 mol% doping); [42] C) Ce doped Fe 3 O 4 (Ce x Fe 3-x O 4 ) at different doping levels from x = 0.01 to x = 0.5 (≈0.3 mol% to ≈16 mol% doping); [80] D) Yb 3+ & Er 3+ codoped Fe 3 O 4 nanoparticle samples (YE), for several doping concentrations, expressed as Y0E0M (0-0 mol%), Y1E1M (1-1 mol%), Y10E1M (10-1 mol%),Y20E1M (20-1 mol%), Y50E1M (50-1 mol%); [105] E) Fe 3 O 4 nanoparticles as a function of Y 3+ doping percentage, namely 0 mol% Y 3+ (W1), 0.1 mol% Y 3+ (Y1), 1 mol% Y 3+ (Y2) and 10 mol% Y 3+ (Y3); [70] F) Dy 3+ doped Fe 3 O 4 flower-like nanoclusters, at doping levels of ≈2.7 mol% to ≈7 mol%. [62] Reproduced with permission.…”