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Showing 1 to 15 of 15 for “"GeTe"”.
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Skyrmions and non-collinear magnetic domains in Fe₃GeTe₂
… interest are heterostructures that utilize Fe3GeTe2, an air sensitive van der Waals (vdW) material known to host nanoscale magnetic whirlpools called skyrmions. The vdW nature of Fe3GeTe2 means we can exfoliate 2D layers that can be easily incorporated into a wide range of devices. Behaving as …
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Quantitative TEM analysis of crystalline and amorphous GeTe-based chalcogenides
The present dissertation reports the results of investigations of the crystallization morphology in single and multi-layer Ge2Sb2Te5 (GST225) samples and the crystallization morphology and local structure in binary Ge53Te47 and quasibinary GeSb2Te4 (GST124) samples. The morphology and structure of …
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Crystal-Amorphous Transformation Via Defect-Templating in Phase-Change Materials
Phase-change materials (PCM) such as GeTe and Ge-Sb-Te alloys are potential candidates for non-volatile memory applications, because they can reversibly and rapidly transform between a crystalline phase and an amorphous phase with medium-range order. Traditionally, crystal-amorphous transformation …
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Sn-Sb-Se based binary and ternary alloys for phase change memory applications
… prototypes are pseudo-binary alloys based on GeTe and Sb2Te3. Among these, Ge2Sb2Te5 has received most attention since it shows fast crystallization speed, high electrical resistivity contrast between the amorphous and crystalline states, high number of overwrite cycles, and high archival …
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Combinatorial material synthesis applied to Ge-Sb-Te based phase change materials
… Therefore, germanium, antimony, tellurium, and GeTe have been used as evaporant materials. By superposing the vapours of the single elements, stoichiometry libraries can be prepared. The resulting compounds have then been compared to the results of well-known sputter prepared GeSbTe compounds in …
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Kombinatorische PVD-Synthese und Strukturuntersuchungen der Ge-Sb-Te-Schichten
… range including the quasi binary line GeTe-Sb2Te3. Therefore homogeneous films and films with a compositional gradient were deposited using a combinatorial PVD technique (magnetron sputtering). The samples with a compositional gradient up to 20 at. % had the following composition in the …
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Role of nanoscale order in the nucleation of amorphous chalcogenide alloys
… measurements of amorphous phase change materials GeTe and N-alloyed GeTe. In GeTe samples that are pre-annealed prior to crystallization, the nanoscale order increases, and is correlated with shorter nucleation times as observed in subsequent laser crystallization experiments. However, after …
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First-principles structure prediction of extreme nanowires
… phase-change material, the potential use of GeTe ENWs as switchable nanoscale memory devices was investigated. The vibrational properties of silver chloride ENWs were also considered, and a novel scheme was developed to predict the Raman spectra of systems which can be decomposed into …
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Optische Eigenschaften von Phasenwechselmaterialien für zukünftige optische und elektronische Speicheranwendungen
… structure. Other phase change materials, like GeTe, do not show this effect. This important and interesting effect was investigated with different methods. For crystalline phase change materials optical properties and electrical properties show similar dependencies on the annealing …
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Electronic and optical properties of phase change alloys studied with ab initio methods
… calculations of the optical absorption of GeTe and Ge1Sb2Te4 within time-dependent density functional theory and many-body perturbation theory have been performed within this work. The results reveal the effect of the change in structural and electronic properties upon amorphization on the …
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The ideal of liberty in the political philosophy of David Hume
There have been two major themes in recent studies of Hume’s political philosophy: on the one hand, the implications, the nature, and the extent of Hume’s anti-rationalistic scepticism; and on the other hand, his continuation of and contribution to the natural law tradition, as it had been …
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Rekristallisationskinetik von Phasenwechselmedien
… rim towards the center, while in the case of (GeTe)x(Sb2Te3)y the crystallization is dominated by fast nucleation and successive growth. It is the goal of this work of understand by the investigation of these two prototype systems the cause for the two different mechanisms. The results of this …
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Ab initio Study of Atomic Dynamics and Thermal Properties of Inorganic Clathrates, Chalcogenides and Perovskite Oxides
… the three; For high symmetrical materials like GeTe, Sb<sub>2</sub>Te<sub>3</sub> and the Kooi structure, the finite displacements are the most appropriate to use and HIPHIVE is useful for calculating vibrational and thermal properties of metastable structures at the finite temperature.
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Quantitative analysis of nanoscale order in amorphous materials by stem-mode fluctuation electron microscopy
… thin films including a-Si, nitrogen-alloyed GeTe and Ge2Sb2Te5. The samples contain a wide variety of ordered states. Comparison of experimental data with the covariance simulation clearly reveals different regimes of nanoscale topological order. STEM-FEM also allows us to distinguish subtle …
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Crystallization of Amorphous Chalcogenide Nano-Regions and Test-Structure Fabrication for Non-Volatile Memories
… we have detailed the crystallization kinetics of GeTe thin film. Nucleation and growth phenomena have been observed by optical microscopy in a large region and corresponding rates and velocities have been found. From these data, the activation energies of each process have been calculated and …