We present the results of the study of the elemental composition and defects of the electronic structure of the surface layer modified by high-dose irradiation (1018–1019 ion/cm2) of highly oriented pyrolytic graphite (UPV-1T) by 30-keV N 2 + and Ar+ ions in the temperature range from 180 to 400°C. The EPR spectra observed during irradiation with argon ions at high temperatures and with nitrogen ions at temperatures near the liquid-nitrogen temperature T = 77 K exhibit anomalously narrow lines which probably result from the exchange interaction inside paramagnetic clusters of displaced carbon atoms. During nitrogen ion irradiation at room and higher temperatures, paramagnetic defects typical of many carbon materials (single EPR lines with g = 2.0027–2.0029) and belonging to carbon atoms bound to one or three nitrogen atoms were detected.

EPR and optical spectra of Cu2+ impregnated into nanoporous glass by β-diketonate from a supercritical solution of CO2 were investigated. It is shown that the environment of Cu2+ is static even at room temperature due to large size of the molecules and the steric factors of the pores. EPR spectra typical of Cu2+ in tetragonally elongated octahedron of D4h symmetry are observed. The local environment is determined by elements of molecule β-DKCu. On the basis of the EPR data, the effect of heat treatment on the evolution of the state of Cu2+ centers after dissociation (at 250°C) of the β-DKCu molecule is found. It is shown that, after the dissociation of the β-DKCu molecule, only 10% Cu2+ contributes EPR spectra. They form complexes with fragments of β-DKCu and are characterized by new EPR parameters. The optical spectrum of Vycor glass annealed at 800oC indicates the potential formation of colloid nanoparticles of metallic Cu.

The spectral properties of nanoporous glasses containing Cu2+ ions, which are introduced into glass pores in the form of organometallic compound of copper β-diketonate dissolved in supercritical CO2, are investigated for the first time. The analysis of the EPR and optical absorption spectra demonstrates that Cu2+ ions are located in octahedral sites with symmetry D4h. It is revealed that the intensity of the EPR spectrum decreases by one order of magnitude after annealing of the glass at a temperature of 200°C, which correlates with the temperature of decomposition of copper β-diketonate molecules (∼250°C) with the formation of CuO or metallic copper. This process is accompanied by a change in the spectrum shape and the spin-Hamiltonian parameters, even though these parameters also correspond to the octahedral environment with symmetry D4hIt is assumed that the remaining Cu2+ ions form new complexes with fragments of decomposed molecules. According to the optical data, the inference is made that high-temperature annealing leads to the formation of copper metal nanoparticles in the glass.

Silica substrates were implanted with Ni+ ions to nominal fluences (F) ranging from 1015 to 6×1016 cm−2 at energy E=160 keV. The anisotropic spectrum of electron paramagnetic resonance with g||=2.49±0.03 and g⊥=2.17±0.03 was observed at 77 and 295 K for the samples implanted to F=(1–3)×1015 cm−2 and was attributed to Ni+ ions with ground state |xy〉 or |x2−y2〉. The single line with g=2.29 and ΔHpp∼14 mT was found at 77 and 295 K for the samples implanted to F=(4–8)×1015 cm−2 and was assigned to clusters of Ni+ ions coupled by exchange interactions. Starting from F=8×1015 cm−2 and at higher fluences the single line with g∼2.2 and ΔHpp∼30–40 mT was observed at room temperature. The behavior of this line as function of measurement temperature indicates its superparamagnetic origin earlier studied by Isobe et al. Optical absorption spectra and transmission electron microscopy confirm the results obtained by other authors concerning the formation of particles of metallic nickel of nanometer size in silica glass implanted with Ni+ to F>1016 cm−2.

Silica substrates were implanted with Ti+ ions to nominal doses (D) ranging from 5×1016 to 6×1017 ions/cm2 at an energy of E=160 keV. The lines of electron paramagnetic resonance (EPR) with g=1.938to1.944 are attributed to Ti3+ with ground state |xy〉 located in tetragonally compressed oxygen octahedron. Computed spectra of some samples implanted with Ti, besides the line at g=1.94, contain two isotropic lines with (g=1.968 and g=1.972) which are assigned to Ti3+ ions entering clusters or compounds of titanium with silicon or oxygen. The greater fraction of implanted Ti exists in non-paramagnetic states. In silica glass implanted with Zr+ (E=195 keV, D=5×1016 and 1017 ions/cm2) Zr3+ ions in the amount of 0.5–1% of implanted Zr are in distorted octahedral environment producing an asymmetric line with g∼1.916 and width ∼14 mT. For fluoroaluminate glass (FAG) implanted with Ti+ (E=150 keV, D=2×1016,5×1016 and 1017cm−2) EPR line at g=1.944 and optical absorption band at ∼475 nm similar to those observed earlier for FAG doped with TiO2 were assigned to Ti3+ ions in tetragonally compressed octahedron. In the EPR spectra of FAG coimplanted with Ti+ (E=150 keV) and F+ (E=90 keV) the triplet centered at g=1.9375 with ratio of intensities of components equal to 1:2:1 and the separation between adjacent components equal to 1.1 mT was observed and attributed to TiF+2 molecular ions. The integrated intensity of this triplet in relation to that of the g∼1.94 single line varies from 0.6% to 2% depending on F+ dose. The decrease in the content of Ti3+ ions with increasing implantation dose is interpreted in terms of chemical sputtering of Ti–F molecules. The g-values of Zr3+ ions incorporated into fluorozirconate glass (FZG) after the implantation of Zr+ ions differ from those obtained earlier for F-center near Zr4+ in X- or γ-ray irradiated FZG. We conclude that some part of the implanted zirconium is incorporated into FZG as Zr3+ in distorted octahedral environment. Structural defects produced in silica and fluoride glasses by Ti+- and Zr+-ion implantation are not discussed.

To study the modified surface layers of graphites and deposited films of sputtered material, the dependences of sputtering yield Y , and ion-electron emission coefficient γ on ion incidence angle and target temperature under high dose 30 keV N+ 2 ion irradiation have been measured. In the angular range θ=0-80° Y and γ increase approximately as inverse cosθ, Y of POCO-AXF-5Q are 1.5 times larger than of MPG-LT. The dependences of γ (T) manifests a step-like behaviour typical for the radiation induced phase transitions. EPR analysis shows that at near room temperatures the point electron defects are typical of carbon and the defects due to carbon atoms interacting with 14 N nuclei. At elevated temperatures (≥ 300°C) there are the defects typical of graphite-like structures. The films deposited on glass collectors shows for cold targets only the defects typical of carbon, for the heated graphites - also the defects associated with C-14N nuclei interaction.

The implantation of transition metal ions in glasses can lead to the formation of nanometer-sized colloidal particles embedded in a thin surface layer. In the present work, silica glasses implanted with Cr+ at energy E=200 keV, for fluences larger than 1017 ions/cm2 were studied by electron paramagnetic resonance, X-ray photoelectron and X-ray-excited Auger electron spectroscopies, visible optical spectroscopy and scanning transmission electron microscopy (TEM). It is shown that Cr is present in silica glass as isolated Cr3+ ions as well as chromium oxides (antiferromagnetic Cr2O3 and ferromagnetic CrO2) and chromium silicides. TEM indicates the presence of almost spherical colloidal particles about 10 nm in diameter.

For fluoroaluminate glass (FAG-36) based on usovite mineral implanted with Ti+ (E=150 keV, D=2×1016cm−2) EPR line at g=1.944 and optical absorption band at ∼475 nm were assigned to Ti3+ ions in compressed octahedron. In EPR spectrum of FAG-36 coimplanted with Ti+ and F+ the triplet centered at g∼1.935 with the splitting of 1.1 mT is attributed to TiF2+ molecular ions.

Copper-doped LiNbO_3 layers prepared by an Cu–Li ion-exchange process are characterized by electronic paramagnetic resonance. It is found that the majority of Cu^2+ ions are coupled by strong exchange interactions which is characteristic of short distances between paramagnetic ions. Such ions are accumulated in a thin layer near the crystal surface and can enter in new crystalline phases formed as a result of the Cu–Li ion exchange. A small amount of Cu^2+ ions is incorporated into weakly distorted LiNbO_3 crystal lattice inside the diffusion layer.

For fluoroaluminate glass (FAG-36) based on usovite mineral implanted with Ti+ (E=150 keV, D=2×1016cm−2) EPR line at g=1.944 and optical absorption band at ∼475 nm were assigned to Ti3+ ions in compressed octahedron. In EPR spectrum of FAG-36 coimplanted with Ti+ and F+ the triplet centered at g∼1.935 with the splitting of 1.1 mT is attributed to TiF2+ molecular ions.

Copper-doped LiNbO3 waveguides were prepared by Cu–Li ion-exchange process. Compositional, structural, and optical analyses were performed by secondary ion mass spectrometry, x-ray diffraction, and m-line spectroscopy, respectively. The chemical state of Cu2+ ions was studied by electron paramagnetic resonance, and the results were correlated with structural modification of the LiNbO3 matrix. Copper incorporation in the crystal took place under different regimes, and it induced a lattice rearrangement with the formation of new crystalline phases. Cu2+ ions were surrounded by tetragonally compressed octahedra with rhombic distortions. Cu:LiNbO3 optical waveguides were formed supporting two optical modes.

Electron paramagnetic resonance (EPR) and optical spectra were studied for fluoride glasses of two base compositions, fluorozirconate glass of 55ZrF4–15BaF2–6LaF3–4AlF3–20NaF (ZBLAN) type and fluoroaluminate glass (FAG) based on mineral usovite. The glasses were doped with fluorides or oxides of transition metals (TM) (V, Cr, Mn, Fe, Cu) in the amount from 0.03 to 0.6 wt%. The doped samples were γ-irradiated at 77 or 300 K to doses from 106 to 1.6×108 rad. It was found that the formation of radiation induced defects (F2−, Zr3+, Y2+, O2− and `central resonance' defects) in these samples are suppressed by TM ions at concentrations of TM fluorides from 0.05 to 0.6 wt% depending on glass composition, the nature of defects, TM, dose of irradiation and the content of oxygen. The results are interpreted in terms of radiation induced redox reactions. It is shown that EPR lines of Cr3+ and Fe3+ ions near g=2 for ZBLAN sample decrease in the intensity or disappear after γ-irradiation of samples with 0.03 or 0.05 CrF3(Cr2O3) or FeF3(Fe2O3). This decrease is attributed to the conversion of Fe3+ ion to Fe2+ by electron trapping. It is shown that the shape of the g∼4.3 line for both fluoride glasses is distorted in comparison with that for unirradiated samples. It is assumed that the distortions are caused by the formation of radiation defects, including EPR-unobservable ones, near Fe3+ sites contributing to the g∼4.3 line.

Spectra of electron paramagnetic resonance (EPR) of sol–gel derived silica glass doped with vanadium (1 wt%) were measured at ∼9 GHz and ∼300 K after various stages of the process (sol→fresh gel→aged gel→heat treated gel→glass). We show that the source of electron paramagnetic resonance spectra of the doped solution of aqua-complexes of vanadyl resides in the gel pores after heat treatment at temperatures Tt⩽973 K. The number of vanadyl ions in a sample decreases with increasing Tt and the remainder is immobilized on the pore surface in local environments in which the spectra of vanadium species becomes undetectable. In the temperature range in which the pores collapse a symmetrically shaped single component with observed g∼1.96 is attributed to V4+ clusters. After a treatment at Tt⩾1023 K the width of this line increases at sample temperatures above 340 K. We assumed that this line is due to the formation of crystalline inclusions of non-stoichiometric VO2 for which insulator–metal transition is commonly observed at ∼340 K. The volume of crystalline phase VO2 is less than the detection limit of X-ray diffraction technique used in the present work. For the samples heat treated at Tt>1073 K the spectrum with hyperfine structure (HFS) attributed to isolated V4+ ions in tetrahedral coordination appears at 77 K. The parameters of spin Hamiltonian of orthorhombic symmetry indicate that the wave function of ground state of V4+ is the |3z2−r2〉 type. The absorption bands with maxima at ∼770 and ∼930 nm are observed in optical spectra of these samples.