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Cabrera, A. L.; Aguayo-Soto, R.

doi:10.1023/a:1019078419537

Cited by 51 publications

(30 citation statements)

References 17 publications

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“…[1][2][3] When a H2 molecule is adsorbed on the surface of bulk Pd, it dissociates into two H atoms which diffuse into the Pd lattice. 4 At room temperature, there are two phases of PdH, designated as α and β phases.…”

Section: Introductionmentioning

confidence: 99%

Effects of hydrogen/deuterium absorption on the magnetic properties of Co/Pd multilayers

et al. 2011

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The effects of hydrogen (H2) and deuterium (D2) absorption were studied in two Co/Pd multilayers with perpendicular magnetic anisotropy (PMA) using polarized neutron reflectivity (PNR). PNR was measured in an external magnetic field H applied in the plane of the sample with the magnetization M confined in the plane for 6.0 T and partially out of plane at 0.65 T. Nominal thicknesses of the Co and Pd layers were 2.5 Å and 21 Å, respectively. Because of these small values, the actual layer chemical composition, thickness, and interface roughness parameters were determined from the nuclear scattering length density profile and its derivative obtained from both x-ray reflectivity and PNR, and uncertainties were determined using Monte Carlo analysis. The PNR showed that although D2 absorption occurred throughout the samples, absorption in the multilayer stack was modest (0.02 D per Pd atom) and thus did not expand. Direct magnetometry showed that H2 absorption decreased the total M at saturation and increased the component of M in the plane of the sample when not at saturation. The PNR magnetic scattering length density revealed that the Pd layers in the multilayer stack were magnetized and that their magnetization was preferentially modified upon D2 absorption. In one sample, a modulation of M with twice the multilayer period was observed at 0.65 T, which increased upon D2 absorption. These results indicate that H2 or D2 absorption decreases both the PMA and total magnetization of the samples. The lack of measurable expansion during absorption 2 indicates that these changes are primarily governed by modification of the electronic structure of the material.

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Section: Introductionmentioning

confidence: 99%

Effects of hydrogen/deuterium absorption on the magnetic properties of Co/Pd multilayers

et al. 2011

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“…Because it is flammable between concentrations of 4% and 75% in air, safety sensors for leak detection are required. In recent years, a variety of sensor concepts has emerged such as resistivitybased [1,2], MOS-based [3,4], optical [5], cantilever-based [6] or nanogap-based sensors [7,8]. Most of these devices make use of palladium (Pd) as the sensitive material because of its highly catalytic surface and a large solubility of atomic hydrogen [9,10].…”

Section: Introductionmentioning

confidence: 99%

Fast and robust hydrogen sensors based on discontinuous palladium films on polyimide, fabricated on a wafer scale

et al. 2010

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Fast hydrogen sensors based on discontinuous palladium (Pd) films on supporting polyimide layers, fabricated by a cost-efficient and full-wafer compatible process, are presented. The films, deposited by electron-beam evaporation with a nominal thickness of 1.5 nm, consist of isolated Pd islands that are separated by nanoscopic gaps. On hydrogenation, the volume expansion of Pd brings initially separated islands into contact which leads to the creation of new electrical pathways through the film. The supporting polyimide layer provides both sufficient elasticity for the Pd nanoclusters to expand on hydrogenation and a sufficiently high surface energy for good adhesion of both film and contacting electrodes. The novel order of the fabrication processes involves a dicing step prior to the Pd deposition and stencil lithography for the patterning of microelectrodes. This allows us to preserve the as-deposited film properties. The devices work at room temperature, show response times of a few seconds and have a low power consumption of some tens of nW.

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“…This is in contrast to common H 2 sensors using bulk Pd, where the increased scattering of conducting electrons at absorbed interstitial H-atoms gives rise to an increase in electrical resistivity. [9][10][11] To optimize such sensors based on ultrathin Pd films, a precise understanding of the electric transport mechanisms and hydrogen sensing behavior as a function of the morphology is essential. The existence of distinct H 2 sensing behavior for continuous and entirely discontinuous Pd structures has been previously reported using various substrate materials such as HOPG, 8 Si, 12 SiO 2 , 5 Si 3 N 4 ͑Ref.…”

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confidence: 99%

The transition in hydrogen sensing behavior in noncontinuous palladium films

Kiefer

Villanueva

Fargier

et al. 2010

Applied Physics Letters

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The morphological transition in ultrathin palladium ͑Pd͒ films around the percolation threshold and the related transition in hydrogen sensing behavior is investigated. We find that besides the transition from continuous to discontinuous Pd, an intermediate -semicontinuous-state must be considered. It shows hydrogen sensing features of both continuous and discontinuous film types, simultaneously. This study focuses on the discontinuous-semicontinuous transition. Experimental evidence is supported by studying the evolution of the electrical resistance with temperature, under hydrogen exposure and after thermal annealing. The results are highly relevant for the optimization of nanogap based hydrogen sensors.

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Untitled

Cited by 51 publications

References 17 publications

Effects of hydrogen/deuterium absorption on the magnetic properties of Co/Pd multilayers

Effects of hydrogen/deuterium absorption on the magnetic properties of Co/Pd multilayers

Fast and robust hydrogen sensors based on discontinuous palladium films on polyimide, fabricated on a wafer scale

The transition in hydrogen sensing behavior in noncontinuous palladium films

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