Electron-Spin Resonances in Gamma-Ray-Irradiated Aluminum Oxide

Gamble, F. T.; Bartram, R.H.; Young, Charles G.; Gilliam, O. R.; Levy, P. W.

doi:10.1103/physrev.134.a589

Cited by 70 publications

(19 citation statements)

References 15 publications

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“…Besides, we have found a weak ESR line with 911 = 2.015 in coloured ruby with small concentrations of chromium ( w 0.01%); the same line was also observed in [5] and by us in coloured corundum. This confirms that in coloured ruby there exist centres which are connected with structural defects of corundum.…”

Section: Colour Centres Connected With Chromiumsupporting

confidence: 74%

“…We have investigated corundum samples [6] which were coloured optically or by y-rays of 8oCo. They also showed the additional absorption bands in the visible and the ultraviolet regions and an ESR line similar to that found in [5]. Under heating both the additional absorption and the ESR disappear and a luminescence is observed: in our samples it is bluish, in [l] a pinkish emission was found.…”

Section: Introductionmentioning

confidence: 54%

“…Additional absorption bands were found to appear in the visible and ultraviolet regions under the action of X-rays [l], y-, reactor, and electron radiation [2, 31, and also under intense illumination [a]. In [5] an ESR line with g = 2.015 was found in a y-coloured corundum. We have investigated corundum samples [6] which were coloured optically or by y-rays of 8oCo.…”

Section: Introductionmentioning

confidence: 98%

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On the Nature of the Colour Centres of Ruby

Arkhangel'skii

Morgenshtern

Neustrev

1968

Physica Status Solidi (b)

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An investigation is made of the spectral dependence of the luminescence quantum yield ratio (q/qo) of coloured and non-coloured ruby and of the yield (7,dd) calculated for additional absorption. It is shown that in the additional absorption (Ak) are bands of different nature.Those with 7)add * 0 are called "active", the others, with 7)add = 0, are called "inactive".The active absorption connected with an electron transition to the conduction band and a following recombination with R-line radiation, is attributed to Cra+ ions, the inactive to Cr4+ ions. Experiments of monochromatic light action on coloured ruby have confirmed this conclusion; light absorbed in the region of active bands bleaches the crystal, whereas bleaching does not occur in the region of inactive bands.

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Section: Colour Centres Connected With Chromiumsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 98%

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On the Nature of the Colour Centres of Ruby

Arkhangel'skii

Morgenshtern

Neustrev

1968

Physica Status Solidi (b)

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“…It is indicated that the EPR signal seems to be dependent on the irradiation source type and dose. Gamma-ray and neutron flux irradiation creates electron-hole pairs, and some of the electrons are trapped at anion vacancies while the corresponding holes are trapped at the charge-deficient cation sites [23]. The energy lost of charged particles gives two contributions: excitations and ionizations of the electrons on one side and direct knock-on collisions with nuclei on the other.…”

Section: Resultsmentioning

confidence: 99%

Electron paramagnetic resonance in gamma-ray, electron and neutron flux irradiated sapphire

Zhang

et al. 2012

Nuclear Instruments and Methods in Physics Research Section B:

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“…16 On assuming that implantation has introduced complexes 20 (e.g., Al 2 O 3 ), which are capable of stabilizing these centers (see Fig. 1), one is able to explain the following: (i) Kondo 1-4 and irradiated films.…”

mentioning

confidence: 99%

Enhanced superconductivity, Kondo behavior, and negative-curvature resistivity of oxygen-irradiated thin films of aluminium

2017

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We followed the evolution of the normal and superconducting properties of Al thin films after each session of various successive oxygen irradiations at ambient temperature. Such irradiated films, similar to the granular ones, exhibit enhanced superconductivity, Kondo behavior and negativecurvature resistivity. Two distinct roles of oxygen are identified: as a damage-causing projectile and as an implanted oxidizing agent. The former gives rise to the processes involved in the conventional recovery stages. The latter, considered within the context of the Cabrera-Mott model, gives rise to a multistep process which involves charges transfer and creation of stabilized vacancies and charged defects. Based on the outcome of this multistep process, we consider (i) the negative curvature resistivity as a manifestation of a thermally-assisted liberation of trapped electric charges, (ii) the Kondo contribution as a spin-flip scattering from paramagnetic, color-center-type defects, and (iii) the enhancement of Tc as being due to a lattice softening facilitated by the stabilized defects and vacancies. The similarity in the phase diagrams of granular and irradiated films as well as the aging effects are discussed along the same line of reasoning.

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Electron-Spin Resonances in Gamma-Ray-Irradiated Aluminum Oxide

Cited by 70 publications

References 15 publications

On the Nature of the Colour Centres of Ruby

On the Nature of the Colour Centres of Ruby

Electron paramagnetic resonance in gamma-ray, electron and neutron flux irradiated sapphire

Enhanced superconductivity, Kondo behavior, and negative-curvature resistivity of oxygen-irradiated thin films of aluminium

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