Hydrogen in Pd/Nb multilayers

Yang, Quan; Schmitz, Guido; Fähler, S.; Krebs, Hans‐Ulrich; Kirchheim, R.

doi:10.1103/physrevb.54.9131

Cited by 57 publications

(47 citation statements)

References 30 publications

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“…In the a-phase region (for low concentrations below H/Ti = 0.1), the compressive stress increases linearly with hydrogen concentration in both plots. Based on the elastic linear theory [22,23], since the films are clamped to elastically hard substrates, the elastic volume expansion due to hydrogen absorption can take place only in out-ofplane direction z at low H concentrations. Thus, the linear increase of compressive stress was confirmed in our stressconcentration plots.…”

Section: Resultsmentioning

confidence: 99%

The influence of films thickness on hydrogenation behavior of titanium thin films

Tal-Gutelmacher¹,

Pundt²,

Kirchheim³

2010

J Mater Sci

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Titanium films of different thicknesses were prepared on sapphire substrates in an UHV chamber, by means of ion beam sputter deposition at room temperature, under Ar-atmosphere at the pressure of 1.5Á10 E -4 mbar. For electrochemical hydrogen loading, the films were covered by a 30-nm thick layer of Pd in order to prevent oxidation and facilitate hydrogen absorption. In situ stress measurements were conducted during step-by-step electrochemical hydrogen charging of the films. XRD measurements using a Phillips X-Pert diffractometer with a Co-Ka radiation were performed before and after hydrogenation in order to investigate the effect of hydrogen loading on the microstructure. The phase boundaries, as well as the stress and strain development during hydrogen absorption, depend strongly on the thickness of the films. The main characteristics of absorption behavior of hydrogen, as well as the thermodynamics and phase boundaries of titanium-hydrogen thin films are discussed in detail with specific emphasis on the influence of films thickness. The obtained results are also compared to literature data on the widely studied titanium-hydrogen bulk system. Shifted phase boundaries and narrowed two-phase field appear in Ti-H film system, which are mainly attributed to the microstructural contribution, as well as to the large stresses in the GPa-range that built up between the films and their substrate.

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Section: Resultsmentioning

confidence: 99%

The influence of films thickness on hydrogenation behavior of titanium thin films

Tal-Gutelmacher¹,

Pundt²,

Kirchheim³

2010

J Mater Sci

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“…2. Diese Gleichung beschreibt die von Yang et al [YAN96] experimentell nachgewiesene Abhängigkeit der H-induzierten Dehnung haftender Schichten. In lateralen Richtungen treten die Spannungen σ xx = σ yy auf.…”

Section: H-induzierte Spannungen In Schichtenunclassified

“…Eine solch hohe Gitterexpansion ist bislang nicht wieder publiziert worden. Im Gegensatz hierzu fanden Yang et al [YAN96], dass die Ausdehnung von Nb/Pd-Schichtpaketen unter H-Beladung mit der theoretischen Ausdehnung im Einklang steht. 1 Reimer et al [REI92,REI93] berichten 1992 von einem weiteren interessanten Verhalten dünner epitaktischer Nb-Schichten unter H-Beladung: Sie entdecken eine Verschmälerung der Rocking-Kurve des (110)-Peaks nach H-Beladung, das 'hydrogen annealing'.…”

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Nanoskalige Metall- Wasserstoff- Systeme

Pundt¹

2005

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“…Fascinating hydrogen-induced property changes have been found, for example rare-earth films which reversibly switch their optical properties from metallic reflecting to transparent [2] or exchange coupled Fe/Nb [3] and Fe/V [4] multilayers which change their ma=~etic coupling and magnetoresistivity effect from antiferromagnetic to ferroma=~etic and vice versa. In some systems like Me/V [5], Fe/V [6] and Nb/Pd [7], giant lattice expansions caused by hydrogen absorption have been reported.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen absorption in epitaxial W/Nb(001) and polycrystalline Fe/Nb(110) multilayers studied in situ by X-ray/neutron scattering techniques and X-ray absorption spectroscopy

Klose

Rehm²,

Fieber‐Erdmann³

et al. 2000

Physica B: Condensed Matter

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Hydrogen can be absorbed in large quantities by 100 i%thin Nb layers embedded in epitaxial W/Nb and polycrystalline Fe/Nb multilayers. The volubility and the hydrogen-induced structural changes of the flost lattice are explored in-situ by smallangle neutron/X-ray reflectometry and high-!angle diffraction. These measurements " \ reveal for both systems that the relative out-~f-plane expansion of the Nb layers is considerably larger than the relative increase of the Nb interplanar spacing indicating. two distinctly different mechanisms of hy~ogen absowtion.~Fe~multilayers, hydrogen expands the Nb interplanm spacing in a continuous way as function of the external pressure. In contrast, the F@ lattice expansion is discontinuous in epitaxial W/Nb multilayers: A jump in the Nb(O02) Bragg reflection position occurs at a critical hydrogen pressure of 1 mbar. In-situ EXAFS spectroscopy also exhibits an irreversible expansion of the Nb lattice in the film plane for p~2> 1 mbar. This can be regarded as a structural phase transition from an exclusively out-of-plane to a three-dimensionally " expanded state at low and high hydrogen pressures, respectively.

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Hydrogen in Pd/Nb multilayers

Cited by 57 publications

References 30 publications

The influence of films thickness on hydrogenation behavior of titanium thin films

The influence of films thickness on hydrogenation behavior of titanium thin films

Nanoskalige Metall- Wasserstoff- Systeme

Hydrogen absorption in epitaxial W/Nb(001) and polycrystalline Fe/Nb(110) multilayers studied in situ by X-ray/neutron scattering techniques and X-ray absorption spectroscopy

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