Optical properties and crystal chemistry of synthetic rutile implanted with cobalt ions

Implantation of high-energy cobalt ions into plates of synthetic rutile has been studied, and absorption, luminescence, and luminescence excitation spectra have been recorded and interpreted. Long-wave luminescence (820 nm) of TiIV 3+ ions in rutile has been revealed; its intensity increased after the cobalt implantation. Analysis of luminescence and luminescence excitation spectra has allowed us to specify the scheme of electron energy levels of rutile and to establish the energy levels of impurity Ti3+ ions occupying vacant octahedrons with the C2h symmetry in structure of the mineral. © Pleiades Publishing, Ltd. 2007

Formation of anisotropic ferromagnetic response in rutile (TiO2) implanted with cobalt ions

The (1 0 0)- and (0 0 1)-monocrystalline plates of rutile (TiO2) were implanted by 40 keV Co+ ions with fluences in wide range of 0.15-1.5 × 1017 ion/cm2 to study the development of ferromagnetism in the diamagnetic TiO2. With increase of fluence the implanted rutile plates reveal sequentially paramagnetic, superparamagnetic, weak ferromagnetic and, eventually, strong anisotropic ferromagnetic response at room temperature. The thermo-magnetic analysis shows that the ferromagnetic samples exhibit two magnetic transitions with temperatures of the ferromagnetic ordering TC1 ∼ 700 K and TC2 ∼ 850 K, correspondingly. Heating of the samples in air strongly suppresses the ferromagnetic phases if the temperature of heating exceeds the corresponding transition temperature. Subsequent high-vacuum annealing restores only the low-temperature ferromagnetic phase. The origin of the two magnetic phases and anisotropy of the ferromagnetism in the Co-implanted rutile are discussed in the model of two cobalt-rich layers with different concentration and valence states of the implanted cobalt. © 2007 Elsevier B.V. All rights reserved

Coloration of natural beryl by iron ion implantation

Natural colorless crystals of Ural beryl were implanted at room temperature with 40 keV Fe+ ions with fluences in the range of 0.5-1.5×1017 ion/cm2. As-implanted samples show dark-grey tone due to radiation damage of beryl crystal. Subsequent thermal annealing of irradiated crystals in oxygen at 600 °C for 30 min results in the color change, to yellowish or yellow-orange tones with golden luster, depending on value of iron fluence. The nature of beryl coloration was studied by optical absorption, Mössbauer and Rutherford backscattering (RBS) spectroscopes. It was established that the thermal treatment of iron-irradiated beryl lead to inward diffusive redistribution of iron ions. An appearance of optical absorption bands connected with charge-transfers O2-→FeVI 3+ and O2-→FeIV 2+, FeIV 3+ determine the yellow tone in colored beryls. Most of implanted iron ions are founded in both tetrahedral FeIV 2+ and octahedral FeVI 3+ sites where they may substitute beryllium and aluminum host ions by isomorphic way. © 2003 Elsevier Science B.V. All rights reserved

Application of Ion Implantation for Synthesis of Copper Nanoparticles in a Zinc Oxide Matrix for Obtaining New Nonlinear Optical Materials

We have obtained a layered composite material by implantation of single crystal zinc oxide (ZnO) substrates with 160-keV Cu+ ions to a dose of 10(16) or 10(17) cm(-2). The composite was studied by linear optical absorption spectroscopy; the nonlinear optical characteristics were determined by means of Z-scanning at a laser radiation wavelength of 532 nm. The appearance of the optical plasmon resonance bands in the spectra indicated that ion implantation to the higher dose provides for the formation of copper nanoparticles in a subsurface layer of ZnO. The new nonlinear optical material comprising metal nanoparticles in a ZnO matrix exhibits the phenomenon of self-defocusing and possesses a high nonlinear absorption coefficient (beta = 2.07 x 10(-3) cm/W). (C) 2004 MAIK "Nauka / Interperiodica"

Ion metal synthesis in viscous organic matter

The viscosity of the irradiated target as new parameter was introduced in ion implantation physics of organic matter. It was experimentally shown that using this parameter one enables to monitor the process of ion synthesis of thin granular impurity films. As an example, the results of high-dose implantation of Co+ and Ag+ ions in viscous epoxy experimenting stages of cure (polymerization) process are presented. It was established by TEM that the mean size, size distributions, form and crystalline structure of the synthesized metal particles depend on both ion beam parameters and viscosity of the epoxy target. The mechanisms of homogeneous nucleation and diffusive growth of metal particles in the low-viscosity epoxy in contrast to heterogeneous nucleation in solid polymers are discussed. The threshold implantation dose that is necessary for the formation of stable metal phase nucleation in a viscous medium was calculated by using the diffusion equation with a continuous Gauss-like source for the implanting impurity. It is shown that the specificity of epoxy polymerization influences the growth and crystalline structure of metal particles at intermediate stages of the epoxy cure process. The preliminary investigation of magnetic, optical and electrical properties of synthesized films is described as well

On the nature of ferromagnetism in oxide semiconductors doped with 3d-elements

The origin and mechanisms of ferromagnetism in the new class of magnetic materials, oxide-diluted magnetic semiconductors (ODMS), are examined in a framework of the Stoner-Anderson model. Within the Green function formalism, a condition (the Stoner criterion) for nucleation of ferromagnetism is obtained for itinerant electrons in the narrow defect (vacancy) band, and an additional contribution due to interaction with 3d magnetic ions is derived. The "trigger" character of the transition to the ferromagnetic state in ODMS is discussed in its dependence on the type and concentration of 3d magnetic impurity dopant. The results of calculations are compared with the experimental data for the spontaneous magnetic moment in semiconducting titanium dioxide (TiO2) doped with 3d magnetic ions and containing various concentrations of oxygen vacancies

Magnetic Resonance Study of Fe-Implanted TiO<inf>2</inf> Rutile

© 2017, Springer-Verlag Wien.Single-crystal (100) and (001) TiO2 rutile substrates have been implanted with 40 keV Fe+ at room temperature with high doses in the range of (0.5–1.5) × 1017 ions/cm2. A ferromagnetic resonance (FMR) signal has been observed for all samples with the intensity and the out-of-plane anisotropy increasing with the implantation dose. The FMR signal has been related to the formation of a percolated metal layer consisting of close-packed iron nanoparticles in the implanted region of TiO2 substrate. Electron spin resonance (ESR) signal of paramagnetic Fe3+ ions substituting Ti4+ positions in the TiO2 rutile structure has been also observed. The dependences of FMR resonance fields on the DC magnetic field orientation reveal a strong in-plane anisotropy for both (100) and (001) substrate planes. An origin of the in-plane anisotropy of FMR signal is attributed to the textured growth of the iron nanoparticles. As result of the nanoparticle growth aligned with respect to the structure of the rutile host, the in-plane magnetic anisotropy of the samples reflects the symmetry of the crystal structure of the TiO2 substrates. Crystallographic directions of the preferential growth of iron nanoparticles have been determined by computer modeling of anisotropic ESR signal of substitutional Fe3+ ions

The reaction of triphenylarsine oxide with ethyl Iodo-acetate leading to triphenyl (carboethoxy)methylarsonium triiodide

New data are presented for some processes accompaning "retro-Arbuzov" reaction of tertiary arsine oxides with halogen-containing reagents. Triphenyl (carboethoxy)methylarsonium triiodide 10a was obtained in the reaction of triphenylarsine oxide la with excess of ethyl iodoacetate 2a. The structure of 10a was established by X-ray single crystal diffraction. © 2004 Wiley Periodicals, Inc

Effects of nickel ions implantation and subsequent thermal annealing on structural and magnetic properties of titanium dioxide

© Published under licence by IOP Publishing Ltd. Wide bandgap semiconducting rutile (TiO2) doped with 3d-elements is a promising material for spintronic applications. In our work a composite material of TiO2:Ni has been formed by using implantation of Ni+ ions into single-crystalline (100)- and (001)- plates of TiO2. Sub-micron magnetic layers of TiO2 containing nickel dopant have been obtained at high implantation fluence of 1×1017 ion/cm2. A part of the implanted samples was then annealed in vacuum at different temperatures T ann 450-1200 K for 30 min. The influence of the implantation fluence, crystalline orientation, as well as subsequent annealing on the structural and magnetic properties of the nickel-implanted TiO2 have been investigated by using X-ray photoelectron spectroscopy, scanning electron microscopy and coil magnetometry techniques

Magnetic and Mössbauer effect studies of ZnO thin film implanted with iron ions to high fluence

© Published under licence by IOP Publishing Ltd.We present the results of magnetic and Mössbauer effect studies of zinc oxide thin film obtained by RF magnetron sputtering and implanted with 40 keV iron ions to a fluence of 1.5•1017 ion/cm2. As-implanted and post-annealed sample shows ferromagnetic properties at room temperature and consists of paramagnetic and ferromagnetic phases according to Mössbauer spectroscopy