Structural, cation distribution, optical and magnetic properties of quaternary Co0.4+xZn0.6-xFe2O4 (x = 0.0, 0.1 and 0.2) and Li doped quinary Co0.4+xZn0.5-xLi0.1Fe2O4 (x = 0.0, 0.05 and 0.1) nanoferrites

Uranium-Incorporated Pyrochlore La2(UxMgxZr1–2x)2O7 Nuclear Waste Form: Structure and Phase Stability

“…41−43 Because of the increased disordering in the lattice by U 6+ and Mg 2+ , their local environments gradually converge, with the U−O and OUO bands under increasing influence from the presence of divalent cations. The downshift in the Raman peaks has also been observed in other systems from chargecoupled substitution, such as Li + −Zn 2+ in Co 0.4 Zn 0.6 Fe 2 O 4 (Fd3̅ m) 41 and Ag + −Zn 2+ in CaWO 4 , 44 The uranyl-type ion (UO 2 2+ ) was also confirmed by spectroscopic methods, as evidenced by PL of the UO bonds. Figure 7 shows the emission spectra of La 2 (U x Mg x Zr 1−2x ) 2 O 7 from λ ex = 230 nm excitations with the schematic of the energy-level diagram for the uranylcontaining systems.…”

“…As the U content increased from x = 0.1 to 0.2, the Raman peaks of U–O and OUO shifted slightly to lower wavenumbers (Table ). Such a downshift can be caused by the low electronic state element occupying a high electronic state. − Because of the increased disordering in the lattice by U 6+ and Mg 2+ , their local environments gradually converge, with the U–O and OUO bands under increasing influence from the presence of divalent cations. The downshift in the Raman peaks has also been observed in other systems from charge-coupled substitution, such as Li + –Zn 2+ in Co 0.4 Zn 0.6 Fe 2 O 4 ( Fd 3̅ m ) and Ag + –Zn 2+ in CaWO 4 , while being absent in the single U-doped RE 2 Hf 2 O 7 , again suggesting its close connection to the local structural modification from coupled low-valence cations.…”

“…Such a downshift can be caused by the low electronic state element occupying a high electronic state. − Because of the increased disordering in the lattice by U 6+ and Mg 2+ , their local environments gradually converge, with the U–O and OUO bands under increasing influence from the presence of divalent cations. The downshift in the Raman peaks has also been observed in other systems from charge-coupled substitution, such as Li + –Zn 2+ in Co 0.4 Zn 0.6 Fe 2 O 4 ( Fd 3̅ m ) and Ag + –Zn 2+ in CaWO 4 , while being absent in the single U-doped RE 2 Hf 2 O 7 , again suggesting its close connection to the local structural modification from coupled low-valence cations. When x increased to 0.3, La 2 (U x Mg x Zr 1–2 x ) 2 O 7 crystallized in defect fluorite, where Mg 2+ and U 6+ both occupy the same eight-coordinated crystallographic site and tend to be randomly distributed, which results in diminishing intensity of octahedra-related Raman modes.…”

Reitveld refinement, structural, optical band gap and low-temperature magnetic characterization of Gd3+ doped spinel cubic CoFe2O4 nanoparticles

“…It depicts that the coercivity, remanent, and saturation magnetization value monotonically increased with a temperature decrease from 300K to 20K. Furthermore, the saturation magnetization in Bohr magneton units (n B ) of the studied nanoferrites was calculated by the formula given below (Shirsath et al, 2011;Lal et al, 2020). where and M S represents the molecular weight and saturation magnetization, correspondingly.…”

An application of CoFe2O4/alginate magnetic beads: drug delivery system of 5-fluorouracil

“…The cubic-spinel structure of transition-metal oxides such as XFe2O4 (X=Ni, Mn, Co, Zn, Mg, Cu or Fe, etc.) is Fe 3+ occupies the tetrahedral sites and X 2+ resides in the octahedral interstitial sites of the closepacked O 2ions (Köseoğlu, 2013;Doğaç et al, 2015;Ramakrishna et al, 2017;Lal et al, 2020;Dhiman et al, 2020;Doğaç & Teke, 2021).…”