Preparations, optical, structural, conductive and magnetic evaluations of RE's (Pr, Y, Gd, Ho, Yb) doped spinel nanoferrites

Upconversion Emission in Tm/Er/Yb Co‐Doped Yttria Stabilized Zirconia Single Crystals

“…Furthermore, the intensity of the Tm 3+ absorption peaks changed with the Tm 2 O 3 contents, but their positions and shapes were unchanged, as expected from the XRD data which indicate that the samples all have the same structure. The intense absorption peak at ~250 nm arises from a charge transfer transition equivalent to the peak at 240 nm in pure ZrO 2 , [ 28 ] and the optical bandgap, $${E_{\rm{g}}}$$, for the matrix can be calculated from this transition using the Tauc equation [ 29 ] $$\begin{equation}{({{\alpha {\text h}\nu }})^2} = {\rm{B}}({\rm{h\nu }} - {{\rm{E}}_g})\end{equation}$$where $$\alpha $$ is the absorption coefficient, hν is the energy of the absorbed photon, and B is a constant. The optical bandgap is obtained by extending the linear region of the $${({{\alpha {\text h}\nu }})^2} - {\rm{h\nu }}$$ plot to its intercept on the x ‐axis ( Figure ).…”

“…Furthermore, the intensity of the Tm 3+ absorption peaks changed with the Tm 2 O 3 contents, but their positions and shapes were unchanged, as expected from the XRD data which indicate that the samples all have the same structure. The intense absorption peak at ˜250 nm arises from a charge transfer transition equivalent to the peak at 240 nm in pure ZrO 2 , [28] and the optical bandgap, E g , for the matrix can be calculated from this transition using the Tauc equation [29] (𝛼h𝜈…”

Sol-gel Synthesized Yb-substituted ?-type Hexagonal Ferrites: Study of Structural, Grain Morphology, Electrical Polarization, Electrical Resistivity, Magnetic and Permeability Properties

“…and tetrahedral (A) positions in the spinel block which might enhance the super exchanged interaction between (A-A), (B-B) and (A-B) sites [32]. The substitution of Yb 3+ ions at A sites favors the transfer of Fe 3+ ions to B sites which decreased the magnetic moments at A sites while the magnetic moments at B sites increased, due to interaction between the sites and due to the occupancy of more Fe 3+ ions which results in the enhancement of net saturation magnetization [33].…”

Complete Micro‐Structural Analysis and Elastic Properties of Sm3+‐Doped Ni‐Mn‐Zn Mixed Spinel Ferrite Nanoparticles

“…Due to high chemical stability, considerable magnetic permeability and high electrical resistivity make these materials suitable for several industrial applications. [ 1–5 ] It is well known that intrinsic properties of ferrites like magnetic saturation, Curie temperature, dielectric losses, and d.c. electrical resistivity are greatly influenced by chemical composition, sintering conditions, type of impurity substitution, and site occupancy by metal cations, etc. [ 6–8 ] These unique properties of spinel ferrites make them favorable candidate for variety of technological applications such as magnetic recording media, magnetic drug delivery system, data storage, biosensors, hyperthermia treatment, magnetic refrigeration, etc.…”

“…Such enactment occurs, because the substituted RE 3+ ions replace Fe 3+ ions from octahedral – B sites. [ 1 ] The addition of RE ion significantly changes the electrical and magnetic properties because its 4f orbital interacts with 3d electrons of transition metal cations. [ 15 ] High ionic radii of RE ions allow them to incorporate in the spinel lattice with very small amount, otherwise secondary phase can be observed.…”