Improving the dielectric behavior of NiO nanoparticles by Samarium doping for electromagnetic applications

Raman spectroscopic and magnetic properties of Europium doped nickel oxide nanoparticles prepared by microwave-assisted hydrothermal method

“…From the diffraction patterns, we can perceive that the Ni0.95E0.5O nanoparticles have broader peaks and relatively lower intensity than the pure NiO nanoparticle. This variation in intensity and peak width indicates that the crystallinity of the Ni0.95E0.5O nanoparticles has decreased compared to the undoped samples, which complies with the results reported in the literature [21][22][23][24].…”

“…Such accumulation of nanoparticles was also observed when NiO nanoparticles were doped with rare earth elements like Pr, Sm, Gd, Er, etc. [21][22][23][24]. These observations indicate that doping causes aggregation of the nanoparticles and increases the interaction between them.…”

“…Since the rare earth elements possess partially filled 4f orbitals, these elements can be utilized as dopants to modulate NiO nanoparticles [19][20][21][22][23]. The structural, magnetic, optical, and dielectric behaviour of rare earth (Y, Pr, Sm, Gd, and Er) doped NiO nanoparticles were extensively studied by Al Boukhari et al [11,[21][22][23][24]. Their investigation shows that rare earth doping increases the bandgap, dielectric constant, electrical conductivities, and magnetization in NiO nanoparticles.…”

Sm-Doped NiO Nanoparticles for Magnetic Memory at Room Temperature

“…The obtained slight lattice expansion agrees with the previous report; however, we did not see any peak splitting (Figure b) . Contrary to the above observation, a contraction has also been reported from Ni 98 Sm 2 O NPs. , The ionic radius of Sm 3+ (109.8 pm) is much larger than that of Ni 2+ (83 pm), which justifies the obtained lattice expansion and suggests that Sm-doping up to 0.5–1% possibly leads to substitution of Ni 2+ ions with Sm 3+ . The above finding is consistent with the observed very weak diffraction peak (marked with “*”) of the Sm 2 O 3 phase for the 2–5% samples .…”

“…At and above 2%, instead of occupying the Ni 2+ sites in the lattice, Sm 3+ ions form a more stable secondary Sm 2 O 3 phase, possibly aggregating around the grain boundary. 29,46,47 From the above discussion, we expect that the substitution of much bigger Sm 3+ ions at the Ni 2+ lattice sites produces lattice strain, altering the metal-oxide polyhedra, and leads to a decline in the crystallinity (i.e., size) of the material.…”