Raman scattering, superconductivity, and phonon density of states of stoichiometric and nonstoichiometric TiN

Spengler, W.; Kaiser, R.; Christensen, A. Nørlund; Müller‐Vogt, G.

doi:10.1103/physrevb.17.1095

Cited by 242 publications

(195 citation statements)

References 16 publications

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“…It is well known that crystalline materials with ordered atomic arrangements but extensive vacancies can exhibit extreme broadening in their Raman and IR spectra, due to disruption of the phonon propagation relations, to result in observation of a vibrational density of states (VDOS) pattern: such effects have been described well for TiN 1-x materials. [31][32][33] Ti-bearing oxides including perovskites such as BaTiO 3 and SrTiO 3 can exhibit electron-phonon coupling and second order Raman scattering effects that can also result in broadening of spectral lines. 34,35 A similar broadening was observed in the Raman spectra of Bi 2 Hf 2 O 7 on heating as it underwent phase changes from a pyrochlore-based structure with ordered bismuth displacements, to one in which bismuth atoms are statistically distributed across a number of sites within a crystallographically more symmetrical unit cell.…”

Section: Raman and Fluorescence Spectroscopy Resultsmentioning

confidence: 99%

Structural Transformations and Disordering in Zirconolite (CaZrTi₂O₇) at High Pressure

et al. 2013

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Abstract:There is interest in identifying novel materials for use in radioactive waste applications and studying their behavior under high pressure conditions. The mineral zirconolite (CaZrTi 2 O 7 ) exists naturally in trace amounts in diamond-bearing deep-seated metamorphic/igneous environments, and it is also identified as a potential ceramic phase for radionuclide sequestration. However, it has been shown to undergo radiation-induced metamictization resulting in amorphous forms. In this study we probed the high pressure structural properties of this pyrochlore-like structure to study its phase transformations and possible amorphization behavior. Combined synchrotron X-ray diffraction and Raman spectroscopy studies reveal a series of high pressure phase transformations. Starting from the ambient pressure monoclinic structure an intermediate phase with P2 1 /m symmetry is produced above 15.6 GPa via a first order transformation resulting in a wide coexistence range. Upon compression to above 56 GPa a disordered metastable phase III with a cotunnite-related structure appears that is recoverable to ambient conditions. We examine the similarity between the zirconolite behavior and the structural evolution of analogous pyrochlore systems under pressure.

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Section: Raman and Fluorescence Spectroscopy Resultsmentioning

confidence: 99%

Structural Transformations and Disordering in Zirconolite (CaZrTi₂O₇) at High Pressure

et al. 2013

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“…2,3 Furthermore, the critical temperature of the TiN films can be controlled over a wide range (0 < T c < 5 K) by varying the N 2 concentration during the deposition. 1,4,5 The superconducting transitions remain sharp over the whole range of T c values. Recent studies of low temperature transport properties of TiN superconducting films thinner than 5 nm show a disorder-driven transition from a superconductor to an insulating phase.…”

mentioning

confidence: 96%

“…All of these make them also suitable for use in nanoscale structures. Bulk TiN material is a superconductor with a transition temperature below 6 K. 1 Experiments have demonstrated that the critical temperature of thin TiN films decreases with decreasing thickness, i.e., with increase of the sheet resistance (in the normal state). 2,3 Furthermore, the critical temperature of the TiN films can be controlled over a wide range (0 < T c < 5 K) by varying the N 2 concentration during the deposition.…”

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confidence: 99%

The electron-phonon relaxation time in thin superconducting titanium nitride films

Кардакова

Finkel

Morozov

et al. 2013

Applied Physics Letters

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We report on the direct measurement of the electron-phonon relaxation time, ! eph , in disordered TiN films. Measured values of ! eph are from 5.5 ns to 88 ns in the 4.2 to 1.7 K temperature range and consistent with a T -3 temperature dependence. The electronic density of states at the Fermi level N 0 is estimated from measured material parameters. The presented results confirm that thin TiN films are promising candidate-materials for ultrasensitive superconducting detectors.

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“…Primarily the vibration of heavy ions near nonmetallic vacancies determines the scattering in the acoustic range, that in the optical range arises from vibration of light atoms adjacent to metallic vacancies. Perfect crystal with fcc structure has O h symmetry, every ion is at a site of inversion symmetry and consequently first-order Raman phonon vibrations are forbidden [33,34]. However, the effective symmetry of magnetron sputtered coatings is usually reduced, owing to the presence of numerous lattice defects.…”

Section: Raman Studiesmentioning

confidence: 99%

Combined reactive/non-reactive DC magnetron sputtering of high temperature composite AlN–TiB2–TiSi2

et al. 2016

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High temperature composite target AlN-TiB 2 -TiSi 2 with heterogeneous distribution of compounds (AlN-50 wt.%; TiB 2 -35 wt.%; TiSi 2 -15 wt.%) is used for sputtering via combined reactive/non-reactive DC magnetron sputtering onto substrate materials either cylindrical polished steel (Fe, 18%-Ni, 12%-Cr, 10%-Ti) 3 mm diameter or monocrystalline silicon. The gradient coating has been produced by sequential non-reactive and reactive sputtering of the target. The structural and morphological properties of the deposited films are analyzed by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The tribo-mechanical properties are studied by means of nanoindentation and nanowear tests. The gradient film is composed of two layers with different microstructure and elemental composition. The first layer with thickness~200 nm is mainly based on light B, C and N as well metal elements Al, Si and Ti. The presence of very well distributed nanocrystals embedded in an amorphous matrix, with crystal sizes ranging from 5 to 40 nm is observed in the second layer~700 nm thickness and composed of Al, Ti, Si, B, and N. Films show very flat surfaces, with roughness around 0.35 nm. The hardness, elastic modulus, elastic recovery (W e ), H/E ⁎ ratio and H 3 /E ⁎2 ratio are determined as 17.55 GPa, 216.7 GPa, 60%, 0.08 and 0.12 GPa, respectively. Nanowear tests demonstrate relatively high wear resistance of the coatings. Samples show promising characteristics for hard protective adaptive coatings and diffusion barriers due to short propagation of dislocations in the amorphous matrix and the elastic and hard nature of the nanocomposite structure.

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Raman scattering, superconductivity, and phonon density of states of stoichiometric and nonstoichiometric TiN

Cited by 242 publications

References 16 publications

Structural Transformations and Disordering in Zirconolite (CaZrTi₂O₇) at High Pressure

Structural Transformations and Disordering in Zirconolite (CaZrTi₂O₇) at High Pressure

The electron-phonon relaxation time in thin superconducting titanium nitride films

Combined reactive/non-reactive DC magnetron sputtering of high temperature composite AlN–TiB2–TiSi2

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Raman scattering, superconductivity, and phonon density of states of stoichiometric and nonstoichiometric TiN

Cited by 242 publications

References 16 publications

Structural Transformations and Disordering in Zirconolite (CaZrTi2O7) at High Pressure

Structural Transformations and Disordering in Zirconolite (CaZrTi2O7) at High Pressure

The electron-phonon relaxation time in thin superconducting titanium nitride films

Combined reactive/non-reactive DC magnetron sputtering of high temperature composite AlN–TiB2–TiSi2

Contact Info

Product

Resources

About

Structural Transformations and Disordering in Zirconolite (CaZrTi₂O₇) at High Pressure

Structural Transformations and Disordering in Zirconolite (CaZrTi₂O₇) at High Pressure