Signatures of nearly compensated magnetism and spin glass behavior in highly frustrated β-Mn-type Mn50Fe25+xAl25-x Heusler alloys.

The present study examines the effect of Fe/Al concentration on the structural and magnetic properties of Mn-rich Mn50Fe25+xAl25-x (x = 5, 10, 15) Heusler alloys through x-ray diffraction, temperature- and field-dependent DC magnetization, thermoremanent magnetization, magnetic memory effect, AC susceptibility measurements, and DFT calculations. The samples crystallize in a cubic β-Mn structure. The trend shows a reduction in lattice parameters (unit cell volume) with the increasing Fe proportion.

Electronic Structure and Transport Properties of BiTe and BiSe Single Crystals.

The electrical resistivity and the Hall effect of topological insulator BiTe and BiSe single crystals were studied in the temperature range from 4.2 to 300 K and in magnetic fields up to 10 T. Theoretical calculations of the electronic structure of these compounds were carried out in density functional approach, taking into account spin-orbit coupling and crystal structure data for temperatures of 5, 50 and 300 K.

Semimetallic, Half-Metallic, Semiconducting, and Metallic States in Gd-Sb Compounds.

The electronic and band structures of the Gd- and Sb-based intermetallic materials have been explored using the theoretical ab initio approach, accounting for strong electron correlations of the Gd-4f electrons. Some of these compounds are being actively investigated because of topological features in these quantum materials. Five compounds were investigated theoretically in this work to demonstrate the variety of electronic properties in the Gd-Sb-based family: GdSb, GdNiSb, GdSb, GdSbSO, and GdSb.

Common Topological Features in Band Structure of RNiSb and RSb Compounds for R = Tb, Dy, Ho.

The electronic and band structures of ternary RNiSb and binary RSb compounds for R = Tb, Dy, Ho, have been investigated using an ab initio method accounting for strong electron correlations in the 4f shell of the rare-earth metals. These ternary compounds are found to be semiconductors with the indirect gap of 0.21, 0.

Nearly compensated ferrimagnetic behaviour and giant exchange bias of hexagonal MnPtAl: experimental and theoretical studies.

We have investigated the MnPtAl Heulser alloy to unravel its structural, magnetic, calorimetric and electronic structure properties. At room temperature, the alloy crystallizes in a hexagonal structure. Magnetization reveals a weak martensitic transition at 307 K, followed by a long range ferrimagnetic transition at 90 K.

Experimental and Theoretical Investigations of Fe-Doped Hexagonal MnNiGe.

We report a comprehensive investigation of MnNiFeGe Heusler alloy to explore its magnetic, caloric, and electrical transport properties. The alloy undergoes a ferromagnetic transition across ∼ 212 K and a weak-antiferromagnetic transition across ∼ 180 K followed by a spin-glass transition below ∼ 51.85 K.

Effect of Doping on the Electronic Structure of the Earth's Lower Mantle Compounds: FeXO with X = C, Al, Si.

The effect of the mutual doping of C, Si, and Al atoms on the electronic structure and magnetic properties of FeXO (X = C, Al, Si) compounds, which are constituent compounds of the Earth's lower mantle, was studied. In our first principles calculations, it was found that doping with carbon for both FeSiO and FeAlO leads to the transition of the compound from a half-metallic state to a metallic one. The values of the magnetic moments of Fe were obtained for pure and doped compounds.

Silver Flowerlike Structures for Surface-Enhanced Raman Spectroscopy.

Micro- and nanoflowers are a class of materials composed of particles with high surface-to-volume ratio. They have been extensively studied in the last decade due to simple preparation protocols and promising applications in biosensing, as drug delivery agents, for water purification, and so on. Flowerlike objects, due to their highly irregular surface, may act also as plasmonic materials, providing resonant coupling between optical waves and surface plasmon excitations.

Non-collinear antiferromagnetism to compensated ferrimagnetism in Ti(FeCo) ( = 0, 0.5 and 1) alloys: experiment and theory.

The manifestation of the structural and magnetic properties of Co substituted TiFe2 is investigated using powder X-ray diffraction, magnetization and density functional theory calculations. The alloys TiFe2 and TiFeCo crystallize in the hexagonal structure (P63/mmc) with a reduction in the lattice parameters of TiFeCo (by about 0.51% in a and 0.

Effect of Electronic Correlations on the Electronic Structure, Magnetic and Optical Properties of the Ternary RCuGe Compounds with R = Tb, Dy, Ho, Er.

In this study, the ab initio and experimental results for RCuGe ternary intermetallics were reported for R = Tb, Dy, Ho, Er. Our theoretical calculations of the electronic structure, employing local spin density approximation accounting for electron-electron correlations in the 4f shell of Tb, Dy, Ho, Er ions were carried in DFT+U method. The optical properties of the RCuGe ternary compounds were studied at a broad range of wavelengths.

Collapse of magnetic moment drives the Mott transition in MnO.

The metal-insulator transition in correlated electron systems, where electron states transform from itinerant to localized, has been one of the central themes of condensed-matter physics for more than half a century. The persistence of this question has been a consequence both of the intricacy of the fundamental issues and the growing recognition of the complexities that arise in real materials, when strong repulsive interactions play the primary role. The initial concept of Mott was based on the relative importance of kinetic hopping (measured by the bandwidth) and onsite repulsion of electrons.