Defect studies of hydrogen-loaded nanocrystalline Gd films

Čı́žek, J.; Procházka, I.; Vlach, Martin; Žaludová, N.; Daniš, S.; Bräuer, G.; Anwand, W.; Mücklich, A.; Gemma, Ryota; Kirchheim, R.; Pundt, Astrid

doi:10.1016/j.apsusc.2008.05.188

Cited by 7 publications

(7 citation statements)

References 9 publications

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“…Yayama and Tomokiyo claimed 12 that Gd α-hydrides can be formed up to hydrogen concentrations 0.35 at.H/f.u. However, both our study and available literature data 14 show that it is rather difficult to avoid formation of the parasitic dihydride GdH 2 phase (β-phase) when preparing α-hydrides. Nevertheless, we succeeded in obtaining several single-phase α-GdH x samples by optimizing (minimizing) the time of the hydrogenation procedure.…”

Section: Resultsmentioning

confidence: 77%

“…Further increasing the hydrogen content causes sequential phase transitions into antiferromagnetic β- ( fcc , GdH 2 ) and γ-phases ( hcp , GdH 3 ) with the ordering temperatures ~20 and 4 K, respectively. Several previous attempts to observe a hydrogen-induced Curie temperature change in coarse-grained Gd and thin films were unsuccessful 12 13 14 . This is probably due to several reasons, including sample purity 15 and finite size effects (for thin films).…”

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confidence: 99%

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Magnetic ordering temperature of nanocrystalline Gd: enhancement of magnetic interactions via hydrogenation-induced “negative” pressure

Терешина

Khmelevskyi

Politova

et al. 2016

Sci Rep

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Gadolinium is a nearly ideal soft-magnetic material. However, one cannot take advantage of its properties at temperatures higher than the room temperature where Gd loses the ferromagnetic ordering. By using high-purity bulk samples with grains ~200 nm in size, we present proof-of-concept measurements of an increased Curie point (TC) and spontaneous magnetization in Gd due to hydrogenation. From first-principles we explain increase of TC in pure Gd due to the addition of hydrogen. We show that the interplay of the characteristic features in the electronic structure of the conduction band at the Fermi level in the high-temperature paramagnetic phase of Gd and “negative” pressure exerted by hydrogen are responsible for the observed effect.

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Section: Resultsmentioning

confidence: 77%

mentioning

confidence: 99%

Magnetic ordering temperature of nanocrystalline Gd: enhancement of magnetic interactions via hydrogenation-induced “negative” pressure

Терешина

Khmelevskyi

Politova

et al. 2016

Sci Rep

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“…A D-D neutron generator, using the drive-in titanium or zirconium target technique, continuously loads the pure titanium or zirconium target with the incident deuterons [4], unlike a D-T neutron generator which uses a prepared tritium hydride target. Therefore, compared with the usual hydrogen loading techniques [5,6], hydrogenation in a D-D neutron generator is achieved by accelerating D + to a desired energy and then implanting it into the desired region, making a highly inhomogeneous local distribution of hydrogen isotopes. Although a series of studies to understand the mechanisms of zirconium hydrogenation have been conducted with ordinary hydrogen loading techniques, such as electrochemical charging and thermal absorption [7,8], reports concerning hydrogenation of zirconium by ion implantation are rare.…”

Section: Introductionmentioning

confidence: 99%

Hydrogenation of zirconium film by implantation of hydrogen ions

Liu¹,

Fang

2017

Plasma Sci. Technol.

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In order to understand the drive-in target in a D-D type neutron generator, it is essential to study the mechanism of the interaction between hydrogen ion beams and the hydrogen-absorbingmetal film. The present research concerns the nucleation of hydride within zirconium film implanted with hydrogen ions. Doses of 30 keV hydrogen ions ranging from 4.30×10 17 to 1.43×10 18 ions cm −2 were loaded into the zirconium film through the ion beam implantation technique. Features of the surface morphology and transformation of phase structures were investigated with scanning electron microscopy, atomic force microscopy and x-ray diffraction. Confirmation of the formation of δ phase zirconium hydride in the implanted samples was first made by x-ray diffraction, and the different stages in the gradual nucleation and growth of zirconium hydride were then observed by atomic force microscope and scanning electron microscopy.

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“…Recent experiments suggest that commercially available, hydrothermally grown ZnO materials contain an appreciable amount of hydrogen. The concentration measured using nuclear reaction analysis is of the order of 0.1 at.% [1]. In this respect, it is useful to briefly summarize suggestions from the literature how hydrogen atoms can be incorporated into the ZnO lattice.…”

Section: Introductionmentioning

confidence: 99%

Vacancy-Hydrogen Complexes in ZnO

Kuriplach

Bräuer²,

Melikhova

et al. 2008

MSF

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Hydrogen is an important impurity in zinc oxide and can be incorporated into the lattice in several ways. Hydrogen can be also bound by vacancies that can be studied using positron annihilation techniques. Here we examine theoretically oxygen and zinc vacancies in ZnO, the latter also with hydrogen atoms inside. Several computational approaches are employed to determine the defect geometries and related positron characteristics. Positron-induced forces are also taken into account. Calculated positron lifetimes are compared with those observed in experiment, which gives an indication of the presence of zinc vacancy-hydrogen complexes in ZnO materials.

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Defect studies of hydrogen-loaded nanocrystalline Gd films

Cited by 7 publications

References 9 publications

Magnetic ordering temperature of nanocrystalline Gd: enhancement of magnetic interactions via hydrogenation-induced “negative” pressure

Magnetic ordering temperature of nanocrystalline Gd: enhancement of magnetic interactions via hydrogenation-induced “negative” pressure

Hydrogenation of zirconium film by implantation of hydrogen ions

Vacancy-Hydrogen Complexes in ZnO

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