A detailed account of the experimental results from optically detected magnetic resonance ͑ODMR͒ studies of grown-in defects in ͑Al͒GaNP alloys, prepared by molecular beam epitaxy, is presented. The experimental procedure and an in-depth analysis by a spin Hamiltonian lead to the identification of two Ga i defects ͑Ga i -A and Ga i -B͒. New information on the electronic properties of these defects and the recombination processes leading to the observation of the ODMR signals will be provided. These defects are deep-level defects. In conditions when the defect is directly involved in radiative recombination of the near-infrared photoluminescence band, the energy level of the Ga i -B defect was estimated to be deeper than ϳ1.2 eV from either the conduction or valence band edge. In most cases, however, these defects act as nonradiative recombination centers, reducing the efficiency of light emission from the alloys. They can thus undermine the performance of potential photonic devices. High thermal stability is observed for these defects.

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The influence of calcination temperature on copper spatial localization in Y-stabilized ZrO2 powders was studied by attenuated total reflection, diffuse reflectance, electron paramagnetic resonance, transmission electron microscopy, electron energy loss, and energy-dispersive X-ray spectroscopies. It was found that calcination temperature rise in the range of 500–700 °C caused the increase of copper concentration in the volume of ZrO2 nanocrystals. This increase was due to Cu in-diffusion from surface complexes that contained copper ions linked with either water molecules or OH groups. This copper in-diffusion led also to an enhancement of absorption band peaked at ~270 nm that was ascribed to the formation of additional oxygen vacancies in nanocrystal volume. Further increasing of calcination temperature from 800 up to 1000 °C resulted in outward Cu diffusion accompanied by a decrease of the intensity of the 270-nm absorption band (i.e., oxygen vacancies’ number), the transformation of ZrO2 tetragonal (cubic) phase to monoclinic one as well as the enhancement of absorption band of dispersed and crystalline CuO in the 600–900 nm range.

A very broad vibrational band ranging from 1000 up to 4000 cm−1 and two relatively sharp bands at 5000 and 5027 cm−1 are found in the Raman scattering spectrum of hydroxyapatite‐containing films obtained by gas detonation spray method. We developed a theoretical model that interprets the broad band as a result of strong interaction between the high‐frequency hydrogen bond vibrations and lattice phonons. Both sharp bands around 5000 cm−1 are assigned to the overtones of v‐OH vibrations. Copyright © 2016 John Wiley & Sons, Ltd.

Detonation-produced hydroxyapatite coatings were studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Raman spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. The source material for detonation spraying was a B-type carbonated hydroxyapatite powder. The coatings consisted of tetracalcium phosphate and apatite. The ratio depended slightly on the degree of crystallinity of the initial powder and processing parameters of the coating preparation. The tetracalcium phosphate phase was homogeneous; the apatite phase contained defects localized on the sixfold axis and consisted of hydroxyapatite and oxyapatite. Technological factors contributing to the transformation of hydroxyapatite powder structure during coating formation by detonation spraying are discussed.

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