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Topic Review
Dense Superconducting Hydrides
To date, about twenty hydrides experiments have been reported to exhibit high-Tc superconductivity and their Tc agree well with the predicted values. However, there are still some controversies existing between the predictions and experiments.
  • 546
  • 20 Dec 2021
Topic Review
Models of the Structure of Humic Substances
Natural organic matter, including humic substances (HS), comprises complex secondary structures with no defined covalent chemical bonds and stabilized by inter- and intra-molecular interactions, such as hydrogen bonding, Van der Waal’s forces, and pi-pi interactions. The latest view describes HS aggregates as a hydrogel-like structure comprised by a hydrophobic core of aromatic residues surrounded by polar and amphiphilic molecules akin a self-assembled soft material. A different view is based on the classification of this material as either mass or surface fractals. The former is intended as made by the clustering of macromolecules generating dendritic networks, while the latter have been modelled in terms of a solvent-impenetrable core surrounded by a layer of lyophilic material. 
  • 507
  • 22 Feb 2023
Topic Review
RMn2Hx Hydrides
Laves phases crystallize in simple structures and are very common intermetallic phases that can form from combinations of elements throughout the periodic table, giving a huge number of known examples. A special feature of AB2 or AB5 phases is the ability to absorb hydrogen.
  • 499
  • 07 Nov 2023
Topic Review
Properties of MXene Products
MXenes are two-dimensional layered materials containing early transition metal carbides, nitrides, and carbonitrides. 
  • 461
  • 03 Apr 2023
Topic Review
The Phase Field Approach
The phase field approach was developed in the last 20 years to handle radiation damage in materials. This approach bridges the gap between atomistic simulations extensively used to model first step of radiation damage at short time and continuum approach at large time. The main advantage of such an approach lies in its ability to compute not only the microstructure at the nanometric scale but also to calculate generalized susceptibilities such as elastic constants under irradiation.
  • 445
  • 05 May 2022
Topic Review
Silicon and Silicon Carbide Recrystallization by Laser Annealing
Modifying material properties within a specific spatial region is a pivotal stage in the fabrication of microelectronic devices. Laser annealing emerges as a compelling technology, offering precise control over the crystalline structure of semiconductor materials and facilitating the activation of doping ions in localized regions. This obviates the necessity for annealing the entire wafer or device. 
  • 370
  • 29 Dec 2023
Topic Review
Magnetic Fluids
Magnetic fluids were historically the first active nano-dispersion material. Despite over half a century of research, interest in these nano-objects continues to grow every year. This is due to the impressive development of nanotechnology, the synthesis of nanoscale structures, and surface-active systems.
  • 356
  • 25 Jan 2024
Topic Review
Wide-Bandgap Semiconductors for Radiation Detection
An overview of wide-bandgap (WBG) semiconductors for radiation detection applications is given. The recent advancements in the fabrication of high-quality wafers have enabled remarkable WBG semiconductor device applications. The most common 4H-SiC, GaN, and β-Ga2O3 devices used for radiation detection are described.
  • 355
  • 04 Mar 2024
Topic Review
Thermo-Mechanical Effects in the Dual Model of Liquids
The Dual Model of Liquids (DML) is a new mesoscopic model of liquids, whose validity and applicability was demonstrated in several cases. It is shown here that DML may even explain crossed effects of Non-Equilibrium Thermodynamics (NET). According to DML, liquids are arranged on a mesoscopic scale by means of aggregates of molecules, or liquid particles. These structures share the liquid world with a population of lattice particles, i.e., elastic waves that interact with the liquid particles by means of an inertial force, allowing the mutual exchange of energy and momentum between the two populations. The hit particle relaxes the acquired energy and momentum due to the interaction, giving them back to the system a step forward and a time-lapse later, alike in a tunnel effect. The transport phenomena in liquids out of equilibrium have been studied since their discoveries, however, no firm theoretical interpretation exists yet. It is demonstrated that the DML may correctly model the thermodiffusion, in particular getting formal expressions for positive and negative Soret coefficient, and another “unexpected” mechano-thermal effect recently discovered in liquids submitted to shear strain, for which the first-ever theoretical interpretation is provided. Both applications of the DML are supported by the comparison with experimental data. The generality of the approach allows us to customize it for other non-equilibrium phenomena of NET.
  • 352
  • 29 Nov 2023
Topic Review
Phase Transitions in Boron Carbide
Phase transitions known to date have been identified due to significant changes of properties. The phase transition near the chemical composition B8C by clear change of the electronic structure. The endothermic temperature-dependent phase transition at 712 K according to the change of specific heat. The high-pressure phase transition at 33.2 GPa by the drastic change of optical appearance from opacity to transparency. These phase transitions affect IR- and Raman-active phonons and other solid-state properties. The phase transitions at B~8C and 712 K mean that a well-defined distorted structure is converted into another one. In the high-pressure phase transition, an apparently well-defined distorted structure changes into a highly ordered one. In all these cases, the distribution of polar C atoms in the icosahedra plays a crucial role.
  • 337
  • 27 Oct 2023
Topic Review
Single Crystal Synthesis of 11 Iron-Based Superconductors
The 11 system in the iron-based superconducting family has become one of the most extensively studied materials in the research of high-temperature superconductivity, due to their simple structure and rich physical properties. Many exotic properties, such as multiband electronic structure, electronic nematicity, topology and antiferromagnetic order, provide strong support for the theory of high-temperature superconductivity, and have been at the forefront of condensed matter physics in the past decade. One noteworthy aspect is that a high upper critical magnetic field, large critical current density and lower toxicity give the 11 system good application prospects.
  • 304
  • 21 Jul 2023
Topic Review
Imaging Techniques for Morphological Characterization of Magnetic Films
Microscopy imaging techniques are critical for the morphological characterization of thin films because they provide nanoscale structural and compositional information that impacts properties. Techniques discussed below reveal grain size, grain boundaries, surface roughness and interfaces, and defects at high resolution. When coupled with spectroscopy, microscopy may provide compositional mapping and magnetic information. This multiscale morphological information is key to elucidating structure–property relationships in thin films.
  • 277
  • 12 Dec 2023
Topic Review
Excess Conductivity Analysis of an YBCO Foam Strut
Magneto-resistance data R(T, B) obtained at temperatures in the range 4.2 K ≤ T ≤ 150 K (applied magnetic fields ranging from 0 to 7 T) were analyzed in the framework of the fluctuation-induced conductivity (FIC) approach using the models of Aslamazov-Larkin (AL) and Lawrence-Doniach (LD). From the R(T, B) curves we determine in a first instance the residual resistivity ρ0, the normal-state resistivity ρn(T), the mean-field transition temperature TcMF (here due to the appearance of two peaks in dρ/dT called Tc1mid and Tc2mid), the temperature T* (the deviation from the linear resistance behavior), and the characteristic temperatures Tconset and Tcoffset. The data of 10% ρn yield information on the irreversibility line (Hirr(T)), and the data of 90% ρn give information on the upper critical field, Hc2(T). This material then serves to obtain the fluctuation induced conductivity (FIC) or excess conductivity. The resulting FIC curves for each applied magnetic field reveal the presence of five distinct fluctuation regimes above the temperature Tcmid, namely, the short-wave (SWF), one-dimensional (1D), two-dimensional (2D), three-dimensional (3D), and critical (CR) fluctuation domains. The analysis of the FIC data enable the coherence length in the direction of the c-axis at zero-temperature (ξc(0)), the lower and upper critical magnetic fields (Bc1, Bc2), the critical current density at T = 0 K (Jc(0)) and several other parameters describing the the material’s superconducting properties to be determined. A proper knowledge of the microstructure of the YBCO foam sample contributes to the understanding of the present data. It is revealed that the minuscule Y-211 particles found along the YBCO grain boundaries alter the excess conductivity and the fluctuation behavior as compared to conventional YBCO samples, leading to a quite high value for Jc(0) for a sample with a non-optimized pinning landscape.
  • 177
  • 28 Aug 2024
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