Nanoscale decomposition of Nb–Ru–O

Mušić, Denis; Geyer, Richard W.; Chen, Yen‐Ting

doi:10.1016/j.ssc.2016.07.011

Cited by 3 publications

(3 citation statements)

References 56 publications

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“…Similarly this holds for boron suboxide based systems [42]. However, already crystalline Nb-Ru-O thin films undergo a phase separation [43]. Owing to possible extensive surface diffusion in vapour phase condensation experiments [30], a fingerprint of this phase separation may be found in an amorphous state as well.…”

Section: Resultsmentioning

confidence: 74%

Topology and electronic structure of flexible (Nb,Ru)O₂thermoelectrics

Mušić

Schnabel

Bednarčı́k

2017

J. Phys.: Condens. Matter

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Using combinatorial reactive sputtering, we have synthesised Nb-Ru-O thin films on Kapton (polyimide) with the Ru/Nb ratio from 0.5 to 1.1 in a dioxide type of environment. Based on correlative analysis, including synchrotron diffraction experiments and density functional theory, the topology of these amorphous samples is characterised by short metal-oxygen bonds and very pronounced metal-metal interactions within the second coordination shell. We suggest that the role of Nb is within bond length reduction and promotion of quantum confinement, giving rise to an increase in the Seebeck coefficient. Furthermore, these Nb-Ru-O thin films are mechanically flexible as there are no crack formation and delamination upon bending or rolling. This may be rationalised as follows. Nb-Ru-O appears ductile due to low topological connectivity and forms strong bonds with Kapton.

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Section: Resultsmentioning

confidence: 74%

Topology and electronic structure of flexible (Nb,Ru)O₂thermoelectrics

Mušić

Schnabel

Bednarčı́k

2017

J. Phys.: Condens. Matter

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“…Amorphous configurations were obtained within the liquid-quench algorithm [23]. This approach, including the system size, was experimentally validated for a similar composition [40]. The experimental composition for the uniform Nb-O and multilayered Nb-O/Ni-Ta-O configurations was considered (see below).…”

Section: Theoretical Methodsmentioning

confidence: 99%

On thermal conductivity of amorphous niobium monoxide

Mušić¹,

Prünte²,

Keuter³

et al. 2020

J. Phys. D: Appl. Phys.

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Thermal conductivity of NbO is studied experimentally and theoretically. Sputtered NbO samples, slightly overstoichiometric in oxygen, are x-ray amorphous with a combined NbO and NbO 2 short-range order, which is consistent with the quantum mechanical data. Upon annealing, NbO 2 crystallites form in the amorphous matrix due to an energetic preference of 44 meV atom −1 over NbO counterparts. The measured thermal conductivity at room temperature using time-domain thermoreflectance is 6.9 W m −1 K −1 , followed by a continuous increase due to electronic contributions, and it yields a total increase of 40 W m −1 K −1 at 650 K partly due to crystallisation. Phonon-phonon scattering can be induced by introducing Ni 0.75 Ta 0.25 O layers in NbO. These multilayers exhibit a thermal conductivity of 5.4 W m −1 K −1 at room temperature and a monotonic drop upon increasing temperature. It is thus feasible to modulate the high-temperature thermal conductivity of amorphous NbO by an order of magnitude. Hence, amorphous NbO may be of interest for thermoelectric devices, sensors and thermal insulation applications.

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“…First, the amorphous (random) structure was obtained within the liquid-quench algorithm [16]. This approach was experimentally validated for a similar composition [45]. Second, metal atoms were displaced to form the multilayer configuration.…”

Section: Theoretical Methodsmentioning

confidence: 99%