Copper-substituted cobalt ferrite nanoparticles: Structural, optical and antibacterial properties

Microstructural, magnetic, and hyperfine characterizations of Cu‐doped cobalt ferrite nanoparticles

“…The shift in observed phonon modes toward lower wave number (red shift) is due to higher atomic mass of Cu 2+ (63.546 g) ions in comparison with Co 2+ (58.933 g) ions which modifies the reduced mass of M–O (M = Co, Cu) bond. The phonon mode position has been calculated using the following relationwhere μ o and μ are the reduced mass of Co–O bond and Cu–O bond while ω o and ω are corresponding phonon wave number . The detailed discussion of elastic parameters obtained from Raman active modes using Waldron's approach has been included in the supplemental materials section.…”

“…The origin of ferrimagnetism in ferrites is due to the exchange interaction between tetrahedral (A) sites and octahedral (B) sites, that is, A-B interaction which is larger than A- Co 2+ (3.87 μ B ) ions in cobalt ferrite leads to weakening of the A-B exchange interaction and decrease in net spin magnetic moment of the system. 5,27,28 The decrease in coercivity with increasing Cu 2+ ions concentration is attributed to the weakening of A-B exchange interaction. The synthesized nanoparticles are single domain in nature and due to high effective anisotropy of cobalt ferrite; the nanoparticles exist in blocked state at room temperature.…”

Enhancing the catalytic activity of recyclable nanocrystalline NiFe2O4 by replacing Ni by Cu

“…Thus, the metal ions located at the octahedral sites facilitate rapid transfer of electrons from borohydride (BH 4 − ) to 4-nitrophenol, which leads to the formation of 4-aminophenol [15]. In the present case, remarkable enhancement of the catalytic performance after introduction of Cu 2+ into the lattice of nickel ferrite could be due to its octahedral site preference [25]. In fact, the presence of Cu 2+ in the octahedral site of the NC2FO is strongly supported by the magnetic and Raman data.…”

“…After replacing 20% Ni 2+ by Cu 2+ in the spinel ferrite, the M s is found to be decreased to 16 emu/g. The decrease in M s is primarily attributed to two factors, firstly, the smaller particle size of NC2FO, and secondly, the reduced number of spins in Cu 2+ compared to that in Ni 2+ in the octahedral sites of the spinel ferrite [25].…”

Structural characterization and magnetic properties of undoped and copper-doped cobalt ferrite nanoparticles prepared by the octanoate coprecipitation route at very low dopant concentrations

“…34 Relative to the other methods, it offers several advantages such as better distribution of the constituents in the resulting ferrites, low operating temperature, low cost and good control of stoichiometry. 7,35 Many studies 10,24,36 have reported on high amounts of substitution, where an increase in Cu content has resulted in a decrease in the magnetization. For example, Jnaneshwara et al 10 synthesized Co 1Àx Cu x Fe 2 O 4 (with x ¼ 0, 0.1, 0.2, 0.3, 0.4, 0.5) by the solution combustion method and showed that the saturation magnetization decreased from 38.5 to 26.7 emu g À1 as the concentration of Cu 2+ increased.…”