We report the phonon and magnetic properties of various well-stabilized Co3O4 nanoparticles. The net valence in cobalt (II)/(III) cation can be obtained by subtracting the Co2+ ions in tetrahedral interstices and Co3+ ions in the octahedral interstices, respectively, which will possess spatial inhomogeneity of its magnetic moment via Co2+ in tetrahedra and Co3+ in octahedral configurations in the normal spinel structure. Furthermore, the distribution of Co2+/Co3+ governed by various external (magnetic field and temperature) and internal (particle size and slightly distorted CoO6 octahedra) sources, have led to phenomena such as a large redshift of phonon-phonon interaction and short-range magnetic correlation in the inverse spinel structure. The outcome of our study is important in terms of the future development of magnetic semiconductor spintronic devices of Co3O4.

Raman and photoluminescence measurements results reveal a positive Poisson ratio in strained ZnO nanoparticles, signaling the short-range electron–phonon coupling effect and an energy red-shift in the PL spectrum.

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We report on the nanosized effect on superconducting properties of Bi nanoparticles (NPs) that extracted from the temperature and applied magnetic field dependent magnetization measurements of bismuth NPs, and revealed an enhanced TC and stronger coupling strength because of increased density of state and softened phonons ωln. A strong electron-phonon coupling (λep = 1.639) to low-lying phonons (ωln = 58 K) is found to be the leading mechanism behind the observed superconductivity with an enhanced TC ∼ 8.22 K and a strong superconducting coupling strength of α = 2.32(1) of 15 nm Bi NPs. Our results are well described by the Allen and Dynes formula within the framework of the McMillan formalism and are in agreement with the Ginzburg-Landau theory calculations.