Core–hole spectroscopies such as x-ray photoelectron spectroscopy (XPS) and high-resolution electron energy loss spectroscopy (HR-EELS) in combination with multiplet calculation are important tools to elucidate the electronic structure of transition metal compounds. This work presents a comparison between the electronic structure obtained by XPS and HR-EELS for polycrystalline perovskite-type Ba_0.9Ca_0.1Ti_0.9Zr_0.1O₃. Raman analysis suggests that Ca²⁺ cations could partly occupy the Ti⁴⁺ cations in the B-site of a perovskite structure with the tetragonal phase. A multiplet structure was determined by XPS for Ti 2p and by HR-EELS for Ca L_2,3 and Ti L_2,3 edges. Octahedral (O_h) symmetry in the crystal field (CF) effects reproduces the local distortion of TiO₆ octahedra. The charge transfer (CT) effects were also considered to reproduce L₃-edge EELS shoulders and the satellite in the Ti 2p XPS region. CF and CT parameters, 10 D_q, (charge transfer energy) Δ, and (Coulomb repulsion energy) U_dd, are reported for future reference. The broadening of the Ti L₂-edge suggests the presence of the Coster–Kronig electron decay process. Multiplet calculation in O_h symmetry for the Ca L_2,3-edge could support the Raman interpretation.

In the present study, biological hydroxyapatite (HA) was obtained from bovine bones through a thermal process. A total of 0% and 1% of silver nanoparticles (Ag-NPs) synthesized from Opuntia ficus (nopal) were added to the biological hydroxyapatite coatings using an atmospheric plasma spray (APS) on a Ti6Al4V substrate. Following this, its antimicrobial efficiency was evaluated against the following bacterial strains: Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. This was conducted according to the Japanese Industrial Standard (JIS) Z2801:2000 “Antimicrobial Product-Test for Antimicrobial Activity and Efficacy”. Scanning electron microscopy (SEM) showed that the silver nanoparticles (Ag-NPs) were evenly distributed on the coating surface. Energy dispersive X-ray spectroscopy (EDX) shows that apatite deposition occurs on a daily basis, maintaining a Ca/P rate between 2.12 and 1.45. Biocompatibility properties were evaluated with osteoblast-like cells (MC3T3-E1) by single-cell gel electrophoresis assay and Tali image cytometry.

In this paper, we discuss a strong red Eu ³⁺ -concentration-dependent emission line associated with an electric dipole transition ( ⁵ D ₀ → ⁷ F ₂ ) at 616 nm in CdMgZnO: x Eu ³⁺ nanocrystals made via a sol–gel synthesis route. Oxygen interstitial defects created by the presence of a mixed-valence state of Eu ³⁺ and Eu ²⁺ ions as rare-earth cations lead to a structural distortion which is confirmed by x-ray photon electron spectroscopy. The Judd–Ofelt intensity parameters, Ω ₂ and Ω ₄ , obtained from the emission spectra, show a trend for Ω ₂ > Ω ₄ that translates to stronger covalence and a stable local structure surrounding the Eu ³⁺ ions in CdMgZnO nanocrystals. The asymmetry ratio ( R _o ), radiative lifetime ( τ rad ), branching ratio β , stimulated emission cross-section, δ e and the gain bandwidth ( δ _e × Δ λ _eff ) for ⁵ D ₀ are computed and analysed. A radiative lifetime ranging from 789 to 984 µ s points to a suitable material for orange-red fluorescent phosphors for lighting and display technologies. The gain bandwidth ( δ _e × Δ λ _eff ), which is dependent on the Eu ³⁺ concentration, suggests the use of the CdMgZnO: x Eu ³⁺ nanocrystal material in fibre amplifiers, while the sample with x = 1.5%, which yields the largest emission cross-section (15.79 × 10 ⁻²² cm ² ), the highest gain bandwidth (28.8 × 10 ⁻²⁸ cm ³ ), and a high branching ratio (71%), is the best candidate for red laser applications.