Optimization of Ball-Milling Process for Preparation of Si-Ge Nanostructured Thermoelectric Materials

Here we report on technical details of preparation of Si-Ge-based nanostructured thermoelectic materials by a mechnical alloying method. It has been shown that for a milling speed of 350 rpm a single Si-Ge phase is formed after milling time less than 6 h. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3530

The evolution of electron dispersion in the series of rare-earth tritelluride compounds obtained from their charge-density-wave properties and susceptibility calculations

We calculated electron susceptibility of rare-earth tritelluride compounds RTe$_3$ as a function of temperature, wave vector and electron-dispersion parameters. Comparison of results obtained with the available experimental data on the transition temperature and on the wave vector of a charge-density wave in these compounds allowed us to predict values and the evolution of electron-dispersion parameters with the variation of atomic number of rare-earth element R.Comment: 6 pages, 6 figure

Magnetocaloric and Magnetic Properties of Ni\u3csub\u3e2\u3c/sub\u3eMn\u3csub\u3e1-x\u3c/sub\u3eCu\u3csub\u3ex\u3c/sub\u3eGa Heusler Alloys: an Insight from the Direct Measurements and \u3ci\u3eab initio\u3c/i\u3e and Monte Carlo Calculations

We calculated magnetic exchange constants and magnetocaloric properties of Ni2Mn1-xCuxGa Heusler alloys by ab initio and Monte Carlo methods. The ab initio study of the influence of the Cu excess x on the strength of magnetic interactions revealed that Cu weakens Mn-Ni interaction and has a complex impact on the Mn-Mn interactions. Theoretically calculated magnetic phase diagram of Ni2Mn1-xCuxGa is in a good agreement with available experimental data. Calculated by the Monte Carlo method the isothermal magnetic entropy change Delta Smag in a Ni2Mn0.75Cu0.25Ga alloy is significantly smaller around the coupled magnetostructural phase transition temperature than the reported earlier experimental Delta Smag. This discrepancy is ascribed to an overestimation of the experimental Delta Smag at the magnetostructural phase transition. Theoretically determined adiabatic temperature change Delta Tad in Ni2Mn0.75Cu0.25Ga agrees well with Delta Tad measured experimentally by a direct method

Strain driven emergence of topological non-triviality in YPdBi thin films

Half-Heusler compounds exhibit a remarkable variety of emergent properties such as heavy-fermion behaviour, unconventional superconductivity and magnetism. Several of these compounds have been predicted to host topologically non-trivial electronic structures. Remarkably, recent theoretical studies have indicated the possibility to induce non-trivial topological surface states in an otherwise trivial half-Heusler system by strain engineering. Here, using magneto-transport measurements and first principles DFT-based simulations, we demonstrate topological surface states on strained [110] oriented thin films of YPdBi grown on (100) MgO. These topological surface states arise in an otherwise trivial semi-metal purely driven by strain. Furthermore, we observe the onset of superconductivity in these strained films highlighting the possibility of engineering a topological superconducting state. Our results demonstrate the critical role played by strain in engineering novel topological states in thin film systems for developing next-generation spintronic devices.Comment: 20 pages, 5 Figure