Understanding the Anomalous Thermoelectric Behavior of Fe-V-W-Al-Based Thin Films.

We investigated the thermoelectric and thermal behavior of Fe-V-W-Al-based thin films prepared using the radio frequency magnetron sputtering technique at different oxygen pressures (0.1-1.0 × 10 Pa) and on different substrates (n, p, and undoped Si).

Metaheuristic aided structural topology optimization method for heat sink design with low electromagnetic interference.

This study investigates the application of the Metaheuristic Aided Structural Topology Optimization (MASTO) method as a novel approach to address the multiphysics design challenge of creating a heat sink with both high heat conductivity and minimal Electromagnetic Interference (EMI). A distinctive 2D layout with elongated fins is examined for electromagnetic traits, highlighting resonance-related EMI concerns. MASTO proves to be a valuable tool for navigating the complex design space, yielding thoughtfully optimized solutions that harmonize efficient heat dissipation with effective EMI control.

Revealing magnetic and physical properties of TbFeAl: experiment and theory.

We report on the magnetic, electrical transport, caloric and electronic structure properties of TbFeAlpolycrystalline alloy using experiment and theory. The alloy crystallizes in tetragonal structure with I4/mmm space group with lattice parameters= 8.7234(5) Å and= 5.

Development of CuSe/Ag(S,Se)-Based Monolithic Thermoelectric Generators for Low-Grade Waste Heat Energy Harvesting.

With the ongoing climate and energy crises, thermoelectric conversion has slowly emerged as a clean and reliable alternative energy source for small Internet of Things (IoT) devices. Commercially available thermoelectric generators (TEGs) are typically composed of expensive and toxic BiTe-based thermoelectric materials and require complicated and energy-intensive device assembly processes. As an alternative solution, we have developed a Ag- and Cu-chalcogenide-based monolithic TEG using simple, quick, and low-energy-cost device fabrication processes for low-grade waste heat recovery for energy harvesting.

Orbital hybridisation effects in B2 phase Cr doped CoMnAl.

We investigate here the magnetic, transport, local structural and electronic properties of CoMn1-xCrAl (= 0, 0.05, 0.1 and 0.

Puddle formation and persistent gaps across the non-mean-field breakdown of superconductivity in overdoped (Pb,Bi)SrCuO.

The cuprate high-temperature superconductors exhibit many unexplained electronic phases, but the superconductivity at high doping is often believed to be governed by conventional mean-field Bardeen-Cooper-Schrieffer theory. However, it was shown that the superfluid density vanishes when the transition temperature goes to zero, in contradiction to expectations from Bardeen-Cooper-Schrieffer theory. Our scanning tunnelling spectroscopy measurements in the overdoped regime of the (Pb,Bi)SrCuO high-temperature superconductor show that this is due to the emergence of nanoscale superconducting puddles in a metallic matrix.

Lattice effects on the physical properties of half-doped perovskite ruthenates.

We investigate the unusual phase transitions in SrRuOand SrCaRu1-xCrO( = 0, 0.05 and 0.1) employing x-ray diffraction, resistivity, magnetic studies and x-ray photoemission spectroscopy.

Effect of the annealing treatment on structural and transport properties of thermoelectric Sm(FeNi)4Sbthin films.

The crystallographic and transport properties of thin films fabricated by pulsed laser deposition and belonging to the Sm(FeNi)Sbfilled skutterudite system were studied with the aim to unveil the effect exerted by temperature and duration of thermal treatments on structural and thermoelectric features. The importance of annealing treatments in Ar atmosphere up to 523 K was recognized, and the thermal treatment performed at 473 K for 3 h was selected as the most effective in improving the material properties. With respect to the corresponding bulk compositions, a significant enhancement in phase purity, as well as an increase in electrical conductivity and a drop in room temperature thermal conductivity, were observed in annealed films.

Enhanced Performance of Monolithic Chalcogenide Thermoelectric Modules for Energy Harvesting via Co-optimization of Experiment and Simulation.

With the development of application of wireless sensor nodes (WSNs), the need for energy harvesting is rapidly increasing. In this study, we designed and fabricated a robust monolithic thermoelectric generator (TEG) using a simple, low-energy, and low-cost device fabrication process. Our monolithic device consists of AgSSe and BiSbTe as n-type and p-type legs, respectively, while the empty space between the legs was filled with highly dense, flexible, and thin AgS that serves as both an insulating spacer and a shock absorber, which potentially augments the robustness of preventing from damage from an external mechanical force.

Synthesis and structural link to the electronic and magneto-transport properties of spin-orbit Mott insulator SrIrO.

We investigate the effect of sample preparation conditions on the link between the structural and physical properties of polycrystalline spin-orbit Mott insulator, SrIrO. The samples were prepared in two batches. With the first batch prepared as per the commonly adopted procedure in literature and the second batch prepared adopting the same procedure as the first batch but with an additional annealing in vacuum.

Magnetic behavior of Ru substituted skyrmion metal MnSi.

We report on the structural and magnetic properties of Ru substituted skyrmion metal MnSi i.e. Mn1-xRuSi for the nominal compositions of0⩽x⩽0.

Synthesis and Characterization of Al- and SnO-Doped ZnO Thermoelectric Thin Films.

The effect of SnO addition (0, 1, 2, 4 wt.%) on thermoelectric properties of -axis oriented Al-doped ZnO thin films (AZO) fabricated by pulsed laser deposition on silica and AlO substrates was investigated. The best thermoelectric performance was obtained on the AZO + 2% SnO thin film grown on silica, with a power factor () of 211.

Unravelling the phonon scattering mechanism in half-Heusler alloys ZrCoIrSb (0, 0.1 and 0.25).

Insight about the scattering mechanisms responsible for reduction in the lattice thermal conductivity () in half-Heusler alloys (HHA) is imperative. In this context, we have thoroughly investigated the temperature response of thermal conductivity of ZrCoIrSb (= 0, 0.1 and 0.

Investigation on the Power Factor of Skutterudite Sm(FeNi)Sb Thin Films: Effects of Deposition and Annealing Temperature.

Filled skutterudites are currently studied as promising thermoelectric materials due to their high power factor and low thermal conductivity. The latter property, in particular, can be enhanced by adding scattering centers, such as the ones deriving from low dimensionality and the presence of interfaces. This work reports on the synthesis and characterization of thin films belonging to the Sm(FeNi)Sb-filled skutterudite system.

Improved Thermoelectric Properties of Re-Substituted Higher Manganese Silicides by Inducing Phonon Scattering and an Energy-Filtering Effect at Grain Boundary Interfaces.

In this study, the effect of the grain boundary density on the transport properties of the Re-substituted higher manganese silicide MnReSi has been investigated. The efficiency of electrical energy conversion from waste heat, mainly in thermoelectric generators, depends on how the thermal conduction is reduced, while the charge-carrier electrons/holes contribute to possess a large magnitude of both the electrical conductivity σ and Seebeck coefficient . In this work, we tried to obtain such a condition with a novel approach of merging the energy-filtering effect at the grain boundaries to improve the power factor (PF) = σ.

Discovery of colossal Seebeck effect in metallic CuSe.

Both electrical conductivity σ and Seebeck coefficient S are functions of carrier concentration being correlated with each other, and the value of power factor Sσ is generally limited to less than 0.01 W m K. Here we report that, under the temperature gradient applied simultaneously to both parallel and perpendicular directions of measurement, a metallic copper selenide, CuSe, shows two sign reversals and colossal values of S exceeding ±2 mV K in a narrow temperature range, 340 K < T < 400 K, where a structure phase transition takes place.

Point nodes persisting far beyond Tc in Bi2212.

In contrast to a complex feature of antinodal state, suffering from competing orders, the pairing gap of cuprates is obtained in the nodal region, which therefore holds the key to the superconducting mechanism. One of the biggest question is whether the point nodal state as a hallmark of d-wave pairing collapses at Tc like the BCS-type superconductors, or it instead survives above Tc turning into the preformed pair state. A difficulty in this issue comes from the small magnitude of the nodal gap, which has been preventing experimentalists from solving it.

Very large thermal rectification in bulk composites consisting partly of icosahedral quasicrystals.

The bulk thermal rectifiers usable at a high temperature above 300 K were developed by making full use of the unusual electron thermal conductivity of icosahedral quasicrystals. The unusual electron thermal conductivity was caused by a synergy effect of quasiperiodicity and by a narrow pseudogap at the Fermi level. The rectification ratio, defined by TRR = [Formula: see text], reached vary large values exceeding 2.

Formation of gapless Fermi arcs and fingerprints of order in the pseudogap state of cuprate superconductors.

We use angle-resolved photoemission spectroscopy and a new quantitative approach based on the partial density of states to study properties of seemingly disconnected portions of the Fermi surface (FS) that are present in the pseudogap state of cuprates called Fermi arcs. We find that the normal state FS collapses very abruptly into Fermi arcs at the pseudogap temperature (T*). Surprisingly, the length of the Fermi arcs remains constant over an extended temperature range between T* and T(pair), consistent with the presence of an ordered state below T*.

Anomalous doping variation of the nodal low-energy feature of superconducting (Bi,Pb)2(Sr,La)2CuO(6+δ) crystals revealed by laser-based angle-resolved photoemission spectroscopy.

The nodal band dispersion in (Bi,Pb)(2)(Sr,La)(2)CuO(6+δ) (Bi2201) is investigated over a wide range of doping by using 7-eV laser-based angle-resolved photoemission spectroscopy. We find that the low-energy band renormalization ("kink"), recently discovered in Bi(2)Sr(2)CaCu(2)O(8+δ) (Bi2212), also occurs in Bi2201, but at a binding energy around half that in Bi2212. Surprisingly, the coupling energy dramatically increases with a decrease of carrier concentration, showing a sharp enhancement across the optimal doping.

Competition between the pseudogap and superconductivity in the high-T(c) copper oxides.

In a classical Bardeen-Cooper-Schrieffer superconductor, pairing and coherence of electrons are established simultaneously below the critical transition temperature (T(c)), giving rise to a gap in the electronic energy spectrum. In the high-T(c) copper oxide superconductors, however, a pseudogap extends above T(c). The relationship between the pseudogap and superconductivity is one of the central issues in this field.

Evidence for a competition between the superconducting state and the pseudogap state of (BiPb)2(SrLa)2CuO6+delta from muon spin rotation experiments.

The in-plane magnetic penetration depth lambda ab in optimally doped (BiPb)2(SrLa)2CuO6+delta (OP Bi2201) was studied by means of muon-spin rotation. The measurements of lambda ab(-2)(T) are inconsistent with a simple model of a d-wave order parameter and a uniform quasiparticle weight around the Fermi surface. The data are well described assuming the angular gap symmetry obtained in ARPES experiments [Phys.

Structure determination of structurally complex Ag36Li64 gamma-brass.

The crystal structure of the Ag(36)Li(64) gamma-brass was determined by analyzing the powder diffraction pattern taken using a synchrotron radiation beam with wavelength 0.50226 A. It turned out that the compound contained 52 atoms in its unit cell with the space group I43m and that the Li atom enters exclusively into inner tetrahedral (IT) and cubo-octahedral (CO) sites, whereas the Ag atom enters into those on outer tetrahedral (OT) and octahedral (OH) sites in the 26-atom cluster.

Evidence for two energy scales in the superconducting state of optimally doped (Bi,Pb)2(Sr,La)2CuO6+delta.

We use angle-resolved photoemission spectroscopy to investigate the energy gap(s) in (Bi,Pb)2(Sr,La)2CuO6+delta. We find that the spectral gap has two components in the superconducting state: a superconducting gap and pseudogap. Differences in their momentum and temperature dependence suggest that they represent two separate energy scales.

Two- to three-dimensional crossover in the electronic structure of (Bi, Pb)2(Sr, La)2CuO(6+delta) from angle-resolved photoemission spectroscopy.

The hole-concentration (x) dependence of the three-dimensional energy-momentum dispersion in (Bi, Pb)2(Sr, La)2CuO(6+delta) has been investigated by angle-resolved photoemission spectroscopy. For a heavily overdoped sample of T(c) < or = 0.5 K, an energy dispersion of approximately 10 meV in width is observed in the vicinity of the (pi, 0) point with varying momentum along the c axis (k(z)).