Search

The reversible semiconductor-to-metal transition of vanadium dioxide (VO2) makes VO2-based coatings a promising candidate for thermochromic smart windows, reducing the energy consumption of buildings. We report low-temperature (320 °C) depositions of thermochromic V1−x−yWxSryO2 films with a thickness of 71–73 nm onto 170–175 nm thick Y-stabilized ZrO2 layers on a 1 mm thick conventional soda-lime glass. The developed deposition technique is based on reactive high-power impulse magnetron sputtering with a pulsed O2 flow feedback control allowing us to prepare crystalline W and Sr co-doped VO2 films of the required stoichiometry without any substrate bias or post-deposition annealing. The W doping of VO2 decreases the transition temperature below 25 °C, while the Sr doping of VO2 increases the integral luminous transmittance, Tlum, significantly due to widening of the visible-range optical bandgap, which is consistent with lowering of the absorption coefficient of films. We present the discussion of the effect of the Sr content in the metal sublattice of VO2 on the electronic and crystal structure of V1−x−yWxSryO2 films, and on their temperature-dependent optical and electrical properties. An optimized V0.855W0.018Sr0.127O2 film exhibits a high Tlum = 56.8% and modulation of the solar energy transmittance ΔTsol = 8.3%, which are 1.50 times and 1.28 times, respectively, higher compared with those of the V0.984W0.016O2 film. The achieved results constitute an important step toward a low-temperature synthesis of large-area thermochromic VO2-based coatings for future smart-window applications, as it is easy to further increase the Tlum and ΔTsol by >6% and >3%, respectively, using a 280 nm thick top SiO2 antireflection layer. [ABSTRACT FROM AUTHOR]

To design smart microwave-absorbing materials (MAMs), it is essential to adjust the corresponding electrical conductivity and dielectric parameters according to variable conditions. However, it is still challenging to concurrently adjust the effective absorbing intensity and frequency range in MAMs due to their interdependent constraints. Here, we developed intelligent MAMs by incorporating core–shell structure vanadium dioxide @ polydopamine (VO2@PDA) powders as polarization loss units, while the subwavelength-sized reduced graphene oxide microspheres (RGOms) were used as conduction loss units. When the temperature is higher than the metal–insulator phase transition temperature of the insulator state VO2 (M), the corresponding metal state VO2 (R) could be produced, which, therefore, contributes to an enhanced interfacial polarization loss due to the significant electrical performance differences between the VO2 (R) and the PDA shell. As an optimized result, the changes of the effective absorption frequency band (▵EAF) and reflection loss (▵RL) of the RV3 composite could be approximately 1.5 GHz and 24 dB, respectively, attributable to the phase transition of VO2. This study provides a novel approach for the adjustment of electromagnetic responses based on dynamic interfacial polarization performance, which offers broader prospects for developing next-generation smart electromagnetic absorption devices with both reversible microwave absorption frequency range and intensities. [ABSTRACT FROM AUTHOR]

Superconducting nanowire single photon detector (SNSPD) is a leading candidate for applications requiring the fundamental limit of light detection at high detection rates. While SNSPD technology employing nanowires from conventional low temperature superconducting detectors is mature with several commercial solutions, other material options with higher transition temperature approaching liquid nitrogen with faster signal responses are actively being explored. In this context, we develop a comprehensive model that predicts the final potential response from an SNSPD incorporating several physical and material aspects. A phase diagram of photon detection is developed that describes the latching phases and the photon sensitivity as a function of biasing current and temperature for both low temperature and high temperature superconductors. On the one hand, while low temperature superconductors are observed to be more sensitive than high temperature superconductors (HTSs) under any given biasing condition, a biasing window for a single photon detection with HTS nanowires is identified. On the other hand, HTS nanowires demonstrate three orders of magnitude faster response times than the low temperature superconductor nanowire at the same biasing condition, making it uniquely suited for several practical applications. [ABSTRACT FROM AUTHOR]

Rare earth substitution in cuprate superconductors has sparked intense interest, driving progress in both fundamental research and advanced technology. In this investigation, we focus on SmBa 2 Cu 3 O 7 − δ (SmBCO), synthesized via the top-seeded melt growth method, with an aim to understand the corresponding vortex phases. Despite the minimal impact on transition temperature (T c) when yttrium in YBa 2 Cu 3 O 7 − δ is replaced by Sm, the critical current density (J c) remains exceptionally high under intense magnetic fields. Introducing Sm 2 Ba 1 Cu 1 O 5 (Sm-211) phase as point defects significantly boosts the pinning potential (U) and pinning force (F p ) and enhances their stability against external magnetic fields. Contrary to other superconductors, the SmBCO sample displays a notable peak effect in the magnetic field-dependent J c , driven by point defects introduced by the Sm-211 phase, which prompts vortex lattice softening and initiates a transition from an ordered to a disordered vortex glass phase, leading to the emergence of a second magnetization peak. Analysis suggests that the primary pinning mechanism in SmBCO involves a combination of normal point and Δ κ pinning. Additionally, investigations of the vortex glass phase beneath the thermally activated flux flow regime indicate that vortices in SmBCO may freeze into a state akin to a 2D vortex glass state. This study leads to a detailed phase diagram that clarifies the evolution of vortex phases in SmBCO. [ABSTRACT FROM AUTHOR]

The correlated semiconductor vanadium dioxide (VO2) exhibits an insulator–metal transition (IMT) near room temperature, which is of interest in various device applications. Precise IMT temperature control is crucial to determine the use cases across technologies such as thermochromic windows, actuators for robots or neuronal oscillators. Doping the cation or anion sites can modulate the IMT by several tens of degrees and control hysteresis. However, modeling the effects of control parameters (e.g., doping concentration, type of dopants) is challenging due to complex experimental procedures and limited data, hindering the use of traditional data-driven machine learning approaches. Symbolic regression (SR) can bridge this gap by identifying nonlinear expressions connecting key input parameters to target properties, even with small data sets. In this work, we develop SR models to capture the IMT trends in VO2 influenced by different dopant parameters. Using experimental data from the literature, our study reveals a dual nature of the IMT temperature with varying tungsten (W) doping concentrations. The symbolic model captures data trends and accounts for experimental variability, providing a complementary approach to first-principles calculations. Our feature-driven analysis across a broader class of dopants informs selectivity and provides qualitative insights into tuning phase transition properties valuable for neuromorphic computing and thermochromic windows. [ABSTRACT FROM AUTHOR]

Pressure-induced polymorphism has recently been demonstrated in several high entropy alloys. This offers a new window into the much-debated issue of phase selection and stability in these systems. Here, we examine the effect of cryogenic temperatures on the pressure-induced transition from face centered cubic to hexagonal close-packed structures of the prototype CoCrFeMnNi (Cantor) alloy. We observe a reduction in the critical pressure for the onset of the polymorphic transition as the temperature decreases, confirming the progressive stabilization of the hexagonal phase with decreasing temperature previously predicted by ab initio calculations accounting for magnetic interactions. We argue that in situ high-pressure experiments at cryogenic temperatures, which suppress time-dependent transformation triggered at higher temperatures, present a unique opportunity to significantly improve our understanding of these complex alloys. [ABSTRACT FROM AUTHOR]

The relaxor ferroelectric crystal Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT), located near the morphotropic phase boundary (MPB), exhibits exceptionally high piezoelectric and electro-optic (EO) responses. Nevertheless, lower optical transparency and phase transition temperature of PMN-PT limit its optical applications. The ternary system Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) holds promise in addressing these challenges with a higher Curie temperature. Additionally, specific ferroelectric domain polarization techniques can eliminate domain scattering, substantially enhancing the transparency of the crystal. In this study, we explore the optical properties of Sm-doped PIN-PMN-PT. We achieve a 2R domain-engineered state by polarizing along the (110) direction of the crystal. The high transparency allows us to extract an effective EO coefficient of up to 431.5 pm/V from the Sm-PIN-PMN-PT crystal at the telecommunications wavelength. Second-harmonic generation (SHG) probing verified the domain-engineered state in Sm-PIN-PMN-PT. The temperature-dependent SHG reveals the ferroelectric phase transition process, laying the groundwork for studying the stability of the EO response. The Sm-PIN-PMN-PT crystal exhibits an exceptionally high EO coefficient, which is crucial for the development of enhanced EO devices with high integration and low driving voltages. [ABSTRACT FROM AUTHOR]

This study explores the dynamics of self-assembly and mesophase formation through molecular dynamics simulations of hexagonal and lamellar systems using a simplified coarse-grained model. We focus on characterizing the order–disorder transitions driven by temperature variations and emphasize the often overlooked disordered regime, which serves as a precursor to periodic mesoscale ordering. Our findings not only underscore the morphological richness of the disordered regime, comparable to that of its periodic counterparts, but also reveal the presence of clustering regimes within isotropic phases, thus corroborating prior experimental and theoretical observations. By employing the dynamic correlation coefficient, this work introduces a novel approach to understanding the fundamental mechanisms of mesophase formation, providing new insights into the complex dynamics of self-assembly. [ABSTRACT FROM AUTHOR]

In this paper, we explored the resistivity behavior of Sb7Se3 thin films on flexible mica. The films maintained their resistance characteristics through various thicknesses and bending cycles. With increasing bends, resistivity and phase transition temperature of both amorphous and crystalline states rose, while the resistance drift coefficient gradually increased. Raman and near infrared experiments confirmed the internal structural changes and bandgap enhancement after bending. Transmission electron microscopy showed enhanced crystallization and uniform element distribution after annealing. Atomic force microscopy observed cracks, explaining the property changes. Additionally, we developed a flexible Sb7Se3 thin-film resistive device with swift reversibility (∼10 ns) regardless of bending, opening new avenues for flexible information storage. [ABSTRACT FROM AUTHOR]

We here present the normal dynamics technique, which recasts the Newton's equations of motion in terms of phonon normal modes by exploiting a proper sampling of the reciprocal space. After introducing the theoretical background, we discuss how the reciprocal space sampling enables us to (i) obtain a computational speedup by selecting which and how many wave vectors of the Brillouin zone will be considered and (ii) account for distortions realized across large atomic distances without the use of large simulation cells. We implemented the approach into an open-source code, which we used to present three case studies: in the first one, we elucidate the general strategy for the sampling of the reciprocal space; in the second one, we illustrate the potential of the approach by studying the stabilization effect of temperature in α-uranium; and in the last one, we investigate the characterization of Raman spectra at different temperatures in MoS2/MX2 transition metal dichalcogenide heterostructures. Finally, we discuss how the procedure is general and can be used to simulate periodic, semiperiodic, and finite systems such as crystals, slabs, nanoclusters, or molecules. [ABSTRACT FROM AUTHOR]

We synthesized the Lu 2 CoCrO 6 compound, multiferroic member of double perovskite system, by sol–gel method and then investigated the crystal structure, magnetization, magnetocaloric effect (MCE), and electrical polarization study. The analysis of powder x-ray diffraction pattern confirms that the monoclinic crystal structure with P2 1 /n space group is better fitting for the Lu 2 CoCrO 6 compound. Distribution between Co and Cr ions at the B-site is not perfectly ordered. Partial ordering between these B-site cations leads to a certain degree of disorder due to the presence of antisite defects and antiphase boundaries. These anti-site disorders (in the B-site) generate various fascinating magnetic phenomena. Although the temperature dependent inverse susceptibility plot shows predominant antiferromagnetic ground state in this system, simultaneously, a second order magnetic phase transition was observed from the Arrott plot. Moreover, the isothermal magnetization study confirms the coexistence of antiferromagnetic (AFM) and ferromagnetic (FM) phases below the transition temperature. The investigation of the magnetocaloric effect shows that the AFM phase of the system converts into the FM phases above critical field values. However, the breakdown of universal behavior of MCE in the paramagnetic region confirms the coexistence of the AFM phase as a secondary phase within the FM matrix. In addition, at lower temperatures, we observe a clear and well-defined ferroelectric hysteresis loop, suggesting ferroelectricity in the material. From these results, we conclude that Lu 2 CoCrO 6 is a multiferroic material in which the coexisting magnetic and multiferroic phases appear to be correlated and weak magneto-electric coupling was also observed. Furthermore, our experimental results help to encourage basic fundamental as well as applied research on rare-earth and transition metal based double perovskite systems due to their complex exchange interaction and multiferroic behavior. [ABSTRACT FROM AUTHOR]

Solid-state refrigeration using barocaloric materials is environmentally friendly and highly efficient, making it a subject of global interest over the past decade. Here, we report giant barocaloric effects in sodium hexafluorophosphate (NaPF6) and sodium hexafluoroarsenate (NaAsF6) that both undergo a cubic-to-rhombohedral phase transition near room temperature. We have determined that the low-temperature phase structure of NaPF6 is a rhombohedral structure with space group R 3 ¯ by neutron powder diffraction. There are three Raman active vibration modes in NaPF6 and NaAsF6, i.e., F2g, Eg, and A1g. The phase transition temperature varies with pressure at a rate of dTt/dP = 250 and 310 K GPa−1 for NaPF6 and NaAsF6. The pressure-induced entropy changes of NaPF6 and NaAsF6 are determined to be around 45.2 and 35.6 J kg−1 K−1, respectively. The saturation driving pressure is about 40 MPa. The pressure-dependent neutron powder diffraction suggests that the barocaloric effects are related to the pressure-induced cubic-to-rhombohedral phase transitions. [ABSTRACT FROM AUTHOR]

The multiferroic Y-type hexaferrites BaxSr2−xMe2Fe12−yAlyO22 (Me = Zn2+, Co2+, Mg2+, etc.) have attracted much attention due to their giant magnetoelectric (ME) effect up to room temperature and low modulated magnetic field by the chemical doping control of the complex magnetic phases. However, the research of substitution between the Me ions is rare. As doping at the Me ion site can combine the advantages of both, e.g., higher magnetic ordering temperature in Co2 and stronger ME coefficient in Mg2 Y-type hexaferrites, herein, we report the stability and switching of magnetoelectric states in the Y-type hexaferrites Ba0.5Sr1.5CoMgFe11AlO22 single crystals. Our results demonstrate that substituting half of the Mg2+ with Co2+ enhances the transition temperature of the alternating longitudinal conical phase to proper screw spin order up to room temperature compared to those Mg2 Y-type hexaferrites. Simultaneous occurrence of in-plane and out-of-plane ferroelectric polarization is observed, alongside comparable spontaneous magnetization. It was found that the in-plane spin-driven polarization can be reversible below 50 K with a substantial ME coefficient α = −8000 ps/m but becomes irreversible at 100 K. This reversal in the sign of the ME coefficient signifies the transition between two distinct ME states at high temperature. The reversibility and irreversibility of spin-induced polarization are discussed within the framework of free energy based on the ferroelectric phase, which prevail in numerous Y-type hexaferrites. Our results provide insights into understanding the role of the Me ions in the magnetoelectric coupling in Y-type hexaferrites. [ABSTRACT FROM AUTHOR]

The multiferroic Y-type hexaferrites BaxSr2−xMe2Fe12−yAlyO22 (Me = Zn2+, Co2+, Mg2+, etc.) have attracted much attention due to their giant magnetoelectric (ME) effect up to room temperature and low modulated magnetic field by the chemical doping control of the complex magnetic phases. However, the research of substitution between the Me ions is rare. As doping at the Me ion site can combine the advantages of both, e.g., higher magnetic ordering temperature in Co2 and stronger ME coefficient in Mg2 Y-type hexaferrites, herein, we report the stability and switching of magnetoelectric states in the Y-type hexaferrites Ba0.5Sr1.5CoMgFe11AlO22 single crystals. Our results demonstrate that substituting half of the Mg2+ with Co2+ enhances the transition temperature of the alternating longitudinal conical phase to proper screw spin order up to room temperature compared to those Mg2 Y-type hexaferrites. Simultaneous occurrence of in-plane and out-of-plane ferroelectric polarization is observed, alongside comparable spontaneous magnetization. It was found that the in-plane spin-driven polarization can be reversible below 50 K with a substantial ME coefficient α = −8000 ps/m but becomes irreversible at 100 K. This reversal in the sign of the ME coefficient signifies the transition between two distinct ME states at high temperature. The reversibility and irreversibility of spin-induced polarization are discussed within the framework of free energy based on the ferroelectric phase, which prevail in numerous Y-type hexaferrites. Our results provide insights into understanding the role of the Me ions in the magnetoelectric coupling in Y-type hexaferrites. [ABSTRACT FROM AUTHOR]

In this study, phase transitions (structural and magnetic) and associated magnetocaloric properties of stoichiometric MnCoGe have been investigated as a function of annealing pressure. Metastable phases were generated by annealing at 800 ° C followed by rapid cooling under pressures up to 6.0 GPa. The x-ray diffraction results reveal that the crystal cell volume of the metastable phases continuously decreases with increasing thermal processing pressure, leading to a decrease in the structural transition temperature. The magnetic and structural transitions merge and form a first-order magnetostructural transition between the ferromagnetic orthorhombic and paramagnetic hexagonal phases over a broad temperature range (>80 K) spanning room temperature, yielding considerable magnetic entropy changes. These findings demonstrate the utility of thermal processing under high pressure, i.e., high-pressure annealing, to control the magnetostructural transitions and associated magnetocaloric properties of MnCoGe without altering its chemical composition. [ABSTRACT FROM AUTHOR]

We report a theoretical investigation of temperature, size, and composition effects on the structural, energetic, and electronic properties of the (La4O6)n, (La2Ce2O7)n, and (Ce4O8)n nanoclusters (NCs) for n = 10, 18. Furthermore, we investigated the single O vacancy formation energy as a function of the geometric location within the NC. Our calculations are based on the combination of force-field molecular dynamics (MD) simulations and density functional theory calculations. We identified a phase transition from disordered to ordered structures for all NCs via MD simulations and structural analysis, e.g., radius changes, radial distribution function, common neighbor analysis, etc. The transition is sharp for La36Ce36O126, La20Ce20O70, and Ce72O144 due to the crystalline domains in the core and less abrupt for Ce40O80, La40O60, and La72O108. As expected, radius changes are abrupt at the transition temperature, as are morphological differences between NCs located below and above the transition temperature. We found a strong dependence on the O vacancy formation energy (Evac) and its location within the NCs. For example, for La40O60, Evac decreases almost linearly as the distance from the geometric center increases; however, the same trend was not observed for Ce40O80, while there are large deviations from the linear trend for La20Ce20O70. Evac has smaller values for Ce40O80 and higher values for La40O60, that is, almost three times, while Evac has intermediate values for mixed oxides, as expected from weighted averages. Therefore, the mixture of one formula unit of La2O3 with two formula units of CeO2 has the effect of increasing the stability of CeO2 (binding energy), which increases the magnitude of the formation energy of the O vacancy. [ABSTRACT FROM AUTHOR]

[001]-textured 0.4P(Mg1/3Nb2/3)O3-0.25PbZrO3-0.35PbTiO3-0.5%MnO2 (Mn-PMN-PZT) ceramics were fabricated by templated grain growth using 2 vol. % BaTiO3 in this paper. Full matrices of dielectric (ɛij), elastic (sij, cij), and piezoelectric (dij) parameters were obtained by the resonance–antiresonance method. The dielectric constant ɛ33T of textured ceramics reaches 2600, which is four times that of random ceramics. Textured Mn-PMN-PZT ceramics exhibit high d33 = 984 pC/N and high k33 = 0.89, which is much larger than d33 = 223 pC/N and k33 = 0.70 of random ceramics. However, ɛ11T of ceramics decreases by about 30% after texturing, and the corresponding shear coupling coefficient k15 also decreases from 0.66 to 0.44, which may be due to the reduction in the angle between spontaneous polarization and transverse direction. Furthermore, the temperature stability of the textured ceramics was evaluated as well. The phase transition temperature TR−T was determined by the impedance method to be 120 °C. The textured Mn-PMN-PZT ceramic shows high temperature stability, which is better than PMN-PT. [ABSTRACT FROM AUTHOR]

UNLABELLED: Invasive mold infections (IMIs) are associated with high morbidity, particularly in immunocompromised patients, with mortality rates between 40% and 80%. Early initiation of appropriate antifungal therapy can substantially improve outcomes, yet early diagnosis remains difficult to establish and often requires multidisciplinary teams evaluating clinical and radiological findings plus supportive mycological findings. Universal digital high-resolution melting (U-dHRM) analysis may enable rapid and robust diagnoses of IMI. A universal fungal assay was developed for U-dHRM and used to generate a database of melt curve signatures for 19 clinically relevant fungal pathogens. A machine learning algorithm (ML) was trained to automatically classify these pathogen curves and detect novel melt curves. Performance was assessed on 73 clinical bronchoalveolar lavage samples from patients suspected of IMI. Novel curves were identified by micropipetting U-dHRM reactions and Sanger sequencing amplicons. U-dHRM achieved 97% overall fungal organism identification accuracy and a turnaround time of ~4 hrs. U-dHRM detected pathogenic molds (Aspergillus, Mucorales, Lomentospora, and Fusarium) in 73% of 30 samples classified as IMI, including mixed infections. Specificity was optimized by requiring the number of pathogenic mold curves detected in a sample to be >8 and a sample volume to be 1 mL, which resulted in 100% specificity in 21 at-risk patients without IMI. U-dHRM showed promise as a separate or combination diagnostic approach to standard mycological tests. U-dHRMs speed, ability to simultaneously identify and quantify clinically relevant mold pathogens in polymicrobial samples, and detect emerging opportunistic pathogens may aid treatment decisions, improving patient outcomes. IMPORTANCE: Improvements in diagnostics for invasive mold infections are urgently needed. This work presents a new molecular detection approach that addresses technical and workflow challenges to provide fast pathogen detection, identification, and quantification that could inform treatment to improve patient outcomes.

Differential scanning fluorimetry (DSF) is a method to determine the apparent melting temperature (Tma) of a purified protein. In DSF, the raw unfolding curves from which Tma is calculated vary widely in shape and complexity. However, the tools available for calculating Tma are only compatible with the simplest of DSF curves, hindering many otherwise straightforward applications of the technology. To overcome this limitation, we designed new mathematical models for Tma calculation that accommodate common forms of variation in DSF curves, including the number of transitions, the presence of high initial signal, and temperature-dependent signal decay. When tested these models against DSFbase, an open-source database of 6235 raw, real-life DSF curves, these models outperformed the existing standard approaches of sigmoid fitting and maximum of the first derivative. To make these models accessible, we created an open-source software and website, DSFworld (https://gestwickilab.shinyapps.io/dsfworld/). In addition to these improved fitting capabilities, DSFworld also includes features that overcome the practical limitations of many analysis workflows, including automatic reformatting of raw data exported from common qPCR instruments, labeling of data based on experimental variables, and flexible interactive plotting. We hope that DSFworld will enable more streamlined and accurate calculation of Tma values for DSF experiments.

Nickel/bismuth (Ni/Bi) bilayers have recently attracted attention due to the occurrence of time-reversal symmetry breaking in the superconducting state. Here, we report on the structural, magnetic, and electric characterization of thin film Ni/Bi bilayers with several Bi thicknesses. We observed the formation of a complex layered structure depending on the Bi thickness caused by the inter-diffusion of Bi and Ni which leads to the stabilization of NiBi 3 at the Bi/Ni interface. The superconducting transition temperature and the transition width are highly dependent on the Bi thickness and the layer structure. Magnetoelectric transport measurements in perpendicular and parallel magnetic fields were used to investigate the temperature-dependent upper critical field within the framework of the anisotropic Ginzburg–Landau theory and the Werthamer–Helfand–Hohenberg model. For thicker samples, we observed a conventional behavior, similar to that shown by NiBi 3 bulk samples, including a small Maki parameter (α M = 0), no spin–orbit scattering (λ S O = 0) and nearly isotropic coherence length (γ = ξ ⊥ (0) / ξ ∥ (0) ≈ 1). The values obtained for these properties are close to those characterizing NiBi 3 single crystals. On the other hand, in very thin samples, the Maki parameter increases to about α M = 2.8. In addition, the coherence length becomes anisotropic (γ = 0.32) and spin–orbit scattering (λ S O = 1.2) must be taken into account. Our results unequivocally show that the properties characterizing the superconducting state in the Ni/Bi are strongly dependent on the sample thickness. [ABSTRACT FROM AUTHOR]

Temperature-dependent Raman spectral studies of BiFeO3 (BFO) films coated on three different substrates, viz., conducting Si (BFO-Si), sapphire (BFO-SAP), and fluorine-doped tin oxide (BFO-FTO), are reported between 123 and 773 K. The activity of Bi–O and Fe–O modes in these samples as a function of temperature shows different spectral features despite having synthesized from the same precursor. To understand the source of these variations, the spectra obtained on the above films were compared with those of bulk BiFeO3 (BFO-bulk) prepared via spark-plasma sintering. As the temperature increases, modes corresponding to the Bi–O activity at low frequency (120–180 cm−1) exhibit a redshift in their positions in all the samples. Between 350 and 550 K, BFO-SAP and BFO-Si samples show discernible anomalies in the positions of modes corresponding to the Fe–O activity (200–500 cm−1), which is not observed in the BFO-bulk and BFO-FTO samples. These anomalies are more pronounced for the modes between 350 and 500 cm−1, suggesting alterations in the Néel transition temperature (∼643 K for BiFeO3). Concurrently, another composite film of BiFeO3–CoFe2O4 coated on the Si substrate is explored. Raman studies on the composite film are used to compare and verify the influence of the substrate and defects on the magnetic ordering as a function of temperature. Our study highlights the significance and relevance of using Raman spectroscopy as a tool to discern various factors leading to local structural and magnetic variation in a given compound. [ABSTRACT FROM AUTHOR]

A thermally driven needle-like (NL) to distorted perovskite (DP) phase transition in SrZrS3 was investigated by means of ab initio free energy calculations accelerated by machine learning. As a first step, a systematic screening of the methods to include long-range interactions in semilocal density functional theory Perdew–Burke–Ernzerhof calculations was performed. Out of the ten correction schemes tested, the Tkatchenko–Scheffler method with iterative Hirshfeld partitioning method was found to yield the best match between calculated and experimental lattice geometries, while predicting the correct order of stability of NL and DP phases at zero temperature. This method was then used in free energy calculations, performed using several approaches, so as to determine the effect of various anharmonicity contributions, such as the anisotropic thermal lattice expansion or the thermally induced internal structure changes, on the phase transition temperature (TNP→DP). Accounting for the full anharmonicity by combining the NPT molecular dynamics data with thermodynamic integration with harmonic reference provided our best estimate of TNL→DP = 867 K. Although this result is ∼150 K lower than the experimental value, it still provides an improvement by nearly 300 K compared to the previous theoretical report by Koocher et al. [Inorg. Chem. 62, 11134–11141 (2023)]. [ABSTRACT FROM AUTHOR]

Antiferromagnetic spintronics is intrigued due to its unique properties that could break through the restrictions in ferromagnets. A 3d/5d transition metal oxide heterostructure is a good platform in antiferromagnetic spintronics research since the strong spin–orbit coupling in 5d oxides may bring about delicate interaction with the correlation energy and motivate unconventional phenomena. Here, the transport and magnetic characters of bilayers composed of antiferromagnetic 3d perovskite NdNiO3 and 5d perovskite SrIrO3 were investigated. The decreased metal–insulator transition and Néel temperature associated with suppressed negative magnetoresistance, emerged spin-glass like phenomenon, and the humped nonlinear Hall effect were observed in NdNiO3/SrIrO3 bilayers, which were absent in NdNiO3 and SrIrO3 pure films. It suggests the important role of interfacial interaction between NdNiO3 and SrIrO3 in modulating heterostructure transport and magnetic behavior and also manifests that complex magnetic structures might be realized in NdNiO3/SrIrO3 bilayers. [ABSTRACT FROM AUTHOR]

PbTiO 3 is a prototypical ferroelectric perovskite that is known to undergo a temperature driven ferroelectric tetragonal to paraelectric cubic phase transition, but the understanding of some key phenomena and associated mechanisms underlying this transition remains unclear. Here, using molecular dynamics simulations based on first-principles effective Hamiltonian, we show the behaviors of the phase transition temperature T c and adiabatic temperature change Δ T of PbTiO 3 under an external electric field and tensile stress along the [001] direction. Our results show that the electric field E induces rising T c via a linear relation T c ∝ 0.3083 E , rendering the phase transition to go from first-order with thermal hysteresis to second-order without thermal hysteresis above ∼ 200 kV/cm; meanwhile, a maximum electrocaloric response Δ T m a x ∼ 34 K is obtained under E = 500 kV/cm. Moreover, external stress (σ z) causes rising T c via a linear relation T c ∝ 160 σ z and improves the electrocaloric response Δ T m a x when combined with the electric field. The present results offer insights into the physical processes and mechanisms that dictate finite-temperature properties of ferroelectric perovskite oxides, laying a foundation for further exploration of this intriguing class of materials. [ABSTRACT FROM AUTHOR]

Carbon-doped Ge2Sb2Te5 (CGST) is a potential candidate in phase change random access memory (PCRAM) with superb thermal stability and ultrahigh cycle endurance. Direct observation of the microstructure evolution of CGST is desirable to uncover the phase transformation mechanism on the relationship of nucleation/crystalline behaviors of the crystalline phase at elevated temperatures and the pristine amorphous phase at room temperature. Here, we investigate the structural evolution of CGST using combined in situ techniques. Our in situ x-ray diffraction and ellipsometry results demonstrate that CGST exhibits a much higher phase transition temperature than undoped one. Temperature-dependent in situ transmission electron microscopy observations further reveal that carbon doping plays a critical role in tailoring the properties of GST by tuning the stochasticity of nucleation/crystallization, stabilizing amorphous and crystalline GST via isolating and refining the grain size at room temperature and elevated temperature. Our work provides detailed information for understanding the microscopic origin of crystallization kinetics of carbon-doped phase change materials toward high-performance PCRAM. [ABSTRACT FROM AUTHOR]

Sr2CoRuO6 in its bulk form shows spin glass behavior with a transition temperature of 95 K, and in its epitaxial thin film, it shows similar behavior with a transition temperature of 135 K. We have studied the structural, electronic, and magnetic properties of a polycrystalline thin film of oxygen-deficient Sr2CoRuO6−δ (SCRO), which shows ferrimagnetic or glassy behavior up to room temperature. The presence of oxygen deficiency causes multivalent cations Co3+ and Co2+ and Ru4+ and Ru5+, which introduces various kinds of magnetic interactions between Co3+–O–Co2+, Co3+–O–Ru4+, Co2+–O–Ru4+, Co3+–O–Ru5+, and Co2+–O–Ru5+ exchange paths, producing unusual exchange bias effects in the single layer thin film of SCRO. The interionic charge transfer between Co and Ru ions as a result of the negative charge transfer energy of the system helps in visualizing the unconventional exchange bias effect in the system. [ABSTRACT FROM AUTHOR]

Frictional heating in cyclotrimethylene trinitramine (RDX) can generate hotspots, which are local regions of elevated temperature that may trigger explosion. In this study, we quantified the characteristic size of the hotspot to be approximately 20 Å based on the width of the nanoscale shear band in shock loading simulations and further examined the temperature rise in RDX crystals during high-speed nanoscratching using molecular dynamics simulations. These simulations were performed under varying sliding velocities, normal loads, and sliding directions to explore the relationship between friction coefficient, shear stress, and localized hotspots. Our results revealed that, despite the anisotropic friction properties, the temperature rise exhibited a consistent dependence on shear stress, with a critical shear stress identified above which the hotspots experienced a sharp increase in the temperature. This temperature transition correlates with localized melting, as demonstrated by the analysis of atomic temperature and bond-length changes. These findings enhance our understanding of the mechanical and thermal stability of energetic materials. [ABSTRACT FROM AUTHOR]

The La1.9Ba0.1Cu1−yZnySnO6 (0 ≤ y ≤ 0.25) (LBCZSO) ceramics were synthesized by the solid-state reaction, and the effect of non-magnetic Zn2+ ion doping on the crystal structure and electrical and magnetic properties is systematically investigated. It is found that all the samples are layered double perovskite with a space group P21/m. The resistivity ρ(T) shows a semiconductor behavior, which follows Mott's 3D variable-range hopping mode. The magnetizations M(T) and the isothermal M-H loops reveal the coexistence of ferromagnetic (FM) and antiferromagnetic (AFM) interactions in the 2D CuO2 layer. With increasing Zn doping at Cu sites, the resistivity ρ(T) increases, the FM transition temperature TC decreases, the FM/AFM interactions weaken/enhance, and the ground state of the system changes from FM to AFM one. It is suggested that cationic electronegativity plays an important role in understanding the transport and magnetic properties of the non-magnetic Zn-doped La1.9Ba0.1CuSnO6, besides the cationic radius. Since the smaller electronegativity of Cu2+ ions compared to that of Sn4+ ions, the CuO6 octahedral distortion with the in-plane compressive strain and out-plane tensile strain is induced by the lattice mismatch between CuO2 and SnO2 layers, forming C-type AF structure with the spin-canted weak FM in 2D CuO2 plane. Since the different cationic electronegativities of Zn2+ and Cu2+ ions, non-magnetic Zn doping leads to the charge transfer between Zn and Cu ions, resulting in the electronic redistribution (transformation) along the ordered Cu–O–Zn chains and non-magnetic Cu+ ions in LBCZSO, which further speeds up the decrease of TC, lead to the abnormal change in the hopping energy W and Curie temperature Θ. Besides, it is confirmed that there is a spin-glass state transition at around 26 K in the non-magnetic Zn doping La1.9Ba0.1CuSnO6 compound. [ABSTRACT FROM AUTHOR]

[Display omitted] • The PPPNV hydrogel possesses outstanding mechanical properties. • VBIMBr endowed the PPPNV hydrogel with excellent anti-freezing and anti-drying ability. • The PPPNV hydrogel strain sensor accurately monitored human physiological signals and motions. • The VPTT of PPPNV hydrogels can be tailored by VBIMBr content. • The PPPNV hydrogel exhibits good thermal sensitivity as a temperature sensor. Conductive hydrogels have received much attention in the field of flexible wearable sensors due to their outstanding flexibility, conductivity, sensitivity and excellent compatibility. However, most conductive hydrogels mainly focus on strain sensors to detect human motion and lack other features such as temperature response. Herein, we prepared a strain and temperature dual responsive ionic conductive hydrogel (PPPNV) with an interpenetrating network structure by introducing a covalent crosslinked network of N -isopropylacrylamide (NIPAAm) and 1-vinyl-3-butylimidazolium bromide (VBIMBr) into the skeleton of the hydrogel composed of polyvinylalcohol (PVA) and polyvinylpyrrolidone (PVP). The PPPNV hydrogel exhibited excellent anti-freezing properties (−37.34 °C) and water retention with high stretchability (∼930 %) and excellent adhesion. As a wearable strain sensor, the PPPNV hydrogel has good responsiveness and stability to a wide range of deformations and exhibits high strain sensitivity (GF=2.6) as well as fast response time. It can detect large and subtle body movements with good signal stability. As wearable temperature sensors, PPPNV hydrogels can detect human physiological signals and respond to temperature changes, and the volumetric phase transition temperature (VPTT) can be easily controlled by adjusting the molar ratio of NIPAAm to VBIMBr. In addition, a bilayer temperature-sensitive hydrogel was prepared with the temperature responsive hydrogel by two-step synthesis, which shows great promising applications in temperature actuators. [ABSTRACT FROM AUTHOR]

The spin-5/2 Blume–Capel model was studied using the mean-field approximation and the Migdal–Kadanoff renormalization group method for two- and three-dimensional systems. We determined the phase diagrams in the (crystal field, temperature) plane where the system exhibited first- and second-order phase transitions as well as isolated critical, bicritical and triple points. In order to show first-order transitions at low temperature, we presented the total magnetization per site and the derivative of the free energy as a function of the crystal field. Moreover, the critical exponents of the system were calculated by linearizing the renormalization transformation at the vicinity of the second-order fixed points. [ABSTRACT FROM AUTHOR]

[Display omitted] Stimuli-responsive poly(N -vinylcaprolactam) (PVCL)-based microgels, which could response to small external environmental changes, have attracted great interests in the fields of biomedicine and nanotechnology. However, the preparation of such microgels meets severe challenge due to their low incorporation efficiency and thermoresponsivity passivation. To address these issues, we select 3-(tert- butoxycarbonyl)- N- vinylcaprolactam (TBVCL), a carboxyl-functionalized VCL derivative, as a comonomer to develop pH/temperature dual-responsive microgels. TBVCL, with a structure similar to VCL, enhances incorporation efficiency and colloidal stability, while reducing thermoresponsivity passivation. The volume phase transition temperature (VPTT) of the microgels can be adjusted over a broad range (19.0–49.5 °C). Notably, the radial swelling ratios of the microgels can be modulated by pH, achieving a maximum swelling ratio of 3. The distinct changes in dissolution-precipitation behavior under different temperatures or pH conditions make these microgels suitable for applications such as smart windows and sensors. Furthermore, this novel approach for fabricating microgels with pH-tunable phase-transition temperatures demonstrates significant potential for the controlled release of nanoparticles (e.g., drugs, catalysts, and quantum dots) and the development of smart nanocrystal-polymer composite sensors. [ABSTRACT FROM AUTHOR]

Vanadium dioxide (VO2) is a phase transition material that undergoes semiconductor-to-metal transition at the temperature of about 68 °C. This extraordinary feature triggered intensive research focused on the controlled synthesis of VO2. In this study, we introduce and investigate an original linker- and solvent-free strategy enabling the production of highly porous VO2 nanoparticle-based films. This technique combines a gas-phase synthesis of vanadium nanoparticles and their subsequent atmospheric pressure thermal oxidation. It is shown that the thermochromic behaviour of such produced nanomaterial is at the fixed oxidation temperature strongly dependent on the oxidation time. Concerning this, it was found that there exists an optimal oxidation time (60 s in our study) that assures the production of crystalline VO2 nanoparticles with the highest, reproducible and temporally stable semiconductor-to-metal transition with the resistive switching ratio close to 2 orders of magnitude and dramatic switching of optical properties in the near infra-red spectral region. [ABSTRACT FROM AUTHOR]

This study investigates the impact of structural configurations, boundary conditions, and atomic number on the Curie transition temperature (Tc) of bulk cobalt (Co) utilizing Monte Carlo simulations. The analysis reveals that the Curie temperature increases as the structure transitions from a simple cubic (SC) to a body-centered cubic (BCC), hexagonal close-packed (HCP), and face-centered cubic (FCC) configuration. The SC structure, exhibiting the lowest Tc, serves as the reference for evaluating these influencing factors. The study also demonstrates that nonperiodic boundary conditions yield the lowest Tc compared to periodic ones. Additionally, an increase in the number of atoms from 4000 to 108,000 under nonperiodic boundary conditions correlates with an increase in Tc. These findings are consistent with experimental data and provide a foundational basis for researchers involved in the synthesis and application of bulk Co in devices, biomedical applications at room temperature, and emerging technologies. [ABSTRACT FROM AUTHOR]

Solid solutions of Ga(0.67–0.67x)CoxCr2S4 have been synthesized based on the cation-deficient spinel Ga0.67Cr2S4 with x = 0–0.3. The structural properties of the synthesized compounds were analyzed by X-ray diffraction (XRD), which revealed that they are single-phase in spinel structure type. The surface morphology was examined using scanning electron microscopy (SEM), and it was determined that the average crystalline particle size is within the range of 0.6–1.0 µm. The EDX analysis confirmed that the composition was in compliance with the intended one and that the sample was homogeneous. A study of the structural properties revealed that the cationic vacancies and gallium ions in the spinel structure are ordered, resulting in the formation of a superstructure within the tetrahedral sublattice. Consequently, the solid solutions under investigation are classified within the F 4 ¯ 3 m space group, rather than Fd 3 ¯ m . This study demonstrates how the magnetic properties of the investigated solid solutions are influenced by the presence of ordered vacancies. A change from paramagnetic to antiferromagnetic with weak ferromagnetism was observed for all compositions. The magnetic transition temperatures (TN = 19–34 K for x = 0–0.3, respectively) have been determined. It has been demonstrated that the substitution of gallium by cobalt leads to an increase in the magnetic transition temperature. Furthermore, an increase in coercivity (HC, from 1.41 to 2.62 kOe) and residual magnetization (MR, from 0.007 to 0.034 μB) was observed in series with increasing cobalt concentration. [ABSTRACT FROM AUTHOR]

Solid solutions of Ga(0.67–0.67x)CoxCr2S4 have been synthesized based on the cation-deficient spinel Ga0.67Cr2S4 with x = 0–0.3. The structural properties of the synthesized compounds were analyzed by X-ray diffraction (XRD), which revealed that they are single-phase in spinel structure type. The surface morphology was examined using scanning electron microscopy (SEM), and it was determined that the average crystalline particle size is within the range of 0.6–1.0 µm. The EDX analysis confirmed that the composition was in compliance with the intended one and that the sample was homogeneous. A study of the structural properties revealed that the cationic vacancies and gallium ions in the spinel structure are ordered, resulting in the formation of a superstructure within the tetrahedral sublattice. Consequently, the solid solutions under investigation are classified within the F 4 ¯ 3 m space group, rather than Fd 3 ¯ m . This study demonstrates how the magnetic properties of the investigated solid solutions are influenced by the presence of ordered vacancies. A change from paramagnetic to antiferromagnetic with weak ferromagnetism was observed for all compositions. The magnetic transition temperatures (TN = 19–34 K for x = 0–0.3, respectively) have been determined. It has been demonstrated that the substitution of gallium by cobalt leads to an increase in the magnetic transition temperature. Furthermore, an increase in coercivity (HC, from 1.41 to 2.62 kOe) and residual magnetization (MR, from 0.007 to 0.034 μB) was observed in series with increasing cobalt concentration. [ABSTRACT FROM AUTHOR]

We report the appearance of superconductivity in single-unit-cell Nd6Ni5O12, exhibiting a transition temperature similar to that of thicker films. In situ synchrotron x-ray scattering performed during growth of the parent phase, Nd6Ni5O16, shows that the necessary layer-by-layer deposition sequence does not follow the sequence of the formula unit but an alternate order due to the relative stability of the perovskite unit cell. We exploit this insight to grow ultrathin Nd6Ni5O16 heterostructures and conduct in situ studies of topotactic reduction, finding that formation of the square-planar phase occurs rapidly and is highly sensitive to reduction temperature, with small deviations from the optimum condition leading to inhomogeneity and the loss of superconductivity. The fluorite layer within the unit cell facilitates reduction by initially stabilizing the square-planar phase in the upper half of the unit cell. Our findings provide insight into growth of the Ruddlesden-Popper nickelates, highlighting the need for in situ studies of the metastable phases key to superconductivity [ABSTRACT FROM AUTHOR]

Barocaloric (BC) materials offer the potential for highly energy-efficient refrigeration by generating heat absorption through the effect of pressure on a solid-solid phase transition. However, very few of the known materials have the required phase transition in the temperature regions necessary for domestic refrigeration or air conditioning. We introduce organic ionic plastic crystals (OIPCs) as a new family of BC materials. OIPCs display subambient transition temperatures, so-called “colossal” entropy changes (92 to 240 joules per kilogram per kelvin), and a high sensitivity to pressure, up to 23.7 kelvin per kilobar. The BC responses achieved with these prototype OIPC-BCs are tunable through structural modification of the ions; this wide matrix of possible combinations of structure and function indicates the scope of OIPCs as a new class of material for efficient and sustainable cooling technologies. [ABSTRACT FROM AUTHOR]

The synthesis temperature of the sample is a key parameter that not only affects the occupancy of cations, but also has a significant impact on the magnetic configuration. In this study, we synthesized pure phase MnCo 2 O 4 powder using a solid-phase reaction method and studied the change of its magnetic configuration with synthesis temperature. Due to the Jahn-Teller distortion caused by octahedral Co2+ and Mn3+ ions, magnetic interactions between octahedral cations dominate in all the samples. When the synthesis temperature is low, some octahedral Co3+ is reduced to Co2+. The appearance of antiferromagnetic interaction between octahedral Co2+ makes the antiferromagnetic characteristics in the sample more prominent. The magnetic configuration in the MnCo 2 O 4 powders synthesized at low temperature undergoes a transition from collinear to non-collinear as the test temperature decreases. As the synthesis temperature increases, a stable collinear magnetic structure is formed, and the ferromagnetic phase gradually becomes dominant. The defined saturation magnetization reaches its maximum at a synthesis temperature of 700 °C, with the Neel temperature of the sample close to the ideal value. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Spin crossover (SCO), characterized by distinct high‐spin (HS) and low‐spin (LS) states, has potential applications in memory, electronic, and electroluminescent devices. The OFF/ON switching of SCO is crucial for obtaining bistable magnetic properties. However, there are few strategies for achieving this switching. Herein, based on a ligand chemical doping strategy, we report an Fe(III) solid solution that can be prepared using a ligand chemical doping strategy, enabling not only the OFF/ON switching of SCO but also the fine‐tuning of the spin transition temperature (Tc) within a 45 K range near room temperature. The experimental results show that when the polar ligand doping ratio reaches 20%, SCO behavior is triggered, and the crystal phase transforms significantly, becoming loose and flexible. Furthermore, Tc can be continuously regulated as the ligand‐doping ratio increases. Density functional theory (DFT) calculations reveal that solid packing‐induced molecular distortion blocks SCO, whereas loosely flexible packing triggers SCO via fluorinated ligand chemical doping. [ABSTRACT FROM AUTHOR]

Passive error correction protects logical information forever (in the thermodynamic limit) by updating the system based only on local information and few-body interactions. A paradigmatic example is the classical two-dimensional Ising model: a Metropolis-style Gibbs sampler retains the sign of the initial magnetization (a logical bit) for thermodynamically long times in the low-temperature phase. Known models of passive quantum error correction similarly exhibit thermodynamic phase transitions to a low-temperature phase wherein logical qubits are protected by thermally stable topological order. Here, in contrast, we show that certain families of constant-rate classical and quantum low-density parity check codes have no thermodynamic phase transitions at nonzero temperature, but nonetheless exhibit ergodicity-breaking dynamical transitions: below a critical nonzero temperature, the mixing time of local Gibbs sampling diverges in the thermodynamic limit. Slow Gibbs sampling of such codes enables fault-tolerant passive quantum error correction using finite-depth circuits. This strategy is well suited to measurement-free quantum error correction, and may present a desirable experimental alternative to conventional quantum error correction based on syndrome measurements and active feedback. It has been commonly assumed that self-correcting quantum memories are only possible in systems with finite-temperature phase transitions to topological order. Here the authors show a complete breakdown of this expectation in quantum low-density parity-check codes. [ABSTRACT FROM AUTHOR]

MgB2 superconductors in the form of tablets doped with Zn(NO3)2·6H2O at different ratios (0–1–2–3% and 4%) by mass were produced in this study. The crystallographic, mechanical, electrical and magnetic properties of the obtained samples were investigated. For this purpose, X-ray diffraction analysis (XRD), microhardness analysis, temperature-dependent electrical resistance measurement (R-T), and magnetic moment change measurement depending on the magnetic field (m-H) were performed on the samples. The critical current densities (Jc) of the samples were calculated using the Bean Method and the Jc-H graph was created. Microhardness analysis was performed using the Vickers Method. Through the Vickers Method, Meyer's Law, Proportional Sample Resistance (PSR) Model, Elastic/Plastic Deformation (EPD) Model and Indentation-Induced Cracking (IIC) Model were used from microhardness modeling. In the analyses, it was determined that plane peaks belonging to MgB2 were seen in all samples, the critical transition temperature (Tc) decreased depending on the increase in the doping ratio from 37.55 to 34.27 K, and there were widenings in the m-H curves. An increase in the Jc value at 0.32 T, depending on the doping ratio of Zn(NO3)2·6H2O, was observed from 3.01 × 101 to 3.23 × 103 A/cm2. It was also observed that all samples exhibited the reverse indentation size effect (RISE) behavior, and the samples became softer with the doping ratio. [ABSTRACT FROM AUTHOR]

There is a solid phase and liquid phase coexistence zone (mushy zone) between the solid phase zone and the liquid phase zone during the ternary compound crystal growth, which is usually clearly displayed in the pseudo-binary phase diagram and can affect the heat transfer and fluid flow within the melting zone. However, it has almost always been neglected in the previous numerical simulation works. To investigate the effects of the mushy zone on the temperature and the melt flow fields during the crystal growth, the GaInSb crystal growth process with the traveling heater method (THM) was numerically simulated. The results indicate that the mushy zone significantly affects the height of the melting zone (HM), the curvature of the growth interface (δR), the axial temperature gradient at the growth solid-liquid interface front, and the flow velocity of the melt in the melting zone during the crystal growth process. As the phase transition temperature interval (ΔT, the temperature difference between the liquidus and solidus in the pseudo-binary phase diagram) increased from 0 K to 1 K, the HM increased by 3.01%, the δR increased by 80.86%, the axial temperature gradient at the growth interface front increased by 111.11%, and the maximum velocity of the melt in the melting zone decreased by 5.05%; as the ΔT increased from 1 K to 7 K, the HM increased by 33.91%, the axial temperature gradient at the growth interface front increased by 42.11%, and the δR decreased by 37.31%; the maximum velocity of the melt in the melting zone decreased by 10.64%. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Spin crossover (SCO), characterized by distinct high‐spin (HS) and low‐spin (LS) states, has potential applications in memory, electronic, and electroluminescent devices. The OFF/ON switching of SCO is crucial for obtaining bistable magnetic properties. However, there are few strategies for achieving this switching. Herein, based on a ligand chemical doping strategy, we report an Fe(III) solid solution that can be prepared using a ligand chemical doping strategy, enabling not only the OFF/ON switching of SCO but also the fine‐tuning of the spin transition temperature (Tc) within a 45 K range near room temperature. The experimental results show that when the polar ligand doping ratio reaches 20%, SCO behavior is triggered, and the crystal phase transforms significantly, becoming loose and flexible. Furthermore, Tc can be continuously regulated as the ligand‐doping ratio increases. Density functional theory (DFT) calculations reveal that solid packing‐induced molecular distortion blocks SCO, whereas loosely flexible packing triggers SCO via fluorinated ligand chemical doping. [ABSTRACT FROM AUTHOR]

Passive temperature sensing systems based on the Internet of Things (IoT) present an efficient, reliable, and convenient solution for temperature monitoring with extensive application prospects and market value. This paper introduces a passive, battery-free, chipless, metasurface temperature sensing tag. The key insight is that the sensing tag uses vanadium dioxide () to solve the problems of measuring distance, large size, and high cost related to active devices. The sensing tag fabricated with tungsten-doped powder demonstrated a significant variation in the reflection magnitude within the temperature range of 34–42 °C. It was achieved through coating, sintering, metasurface design, and ion beam etching. Experimental results showed that the square resistance of the prepared coating decreased from 1003 to 90 as the temperature increased from 34 to 42 °C. Additionally, the reflection magnitude of the tag significantly increased with the temperature decrease in the 3.5–5.27 GHz frequency band. These results indicate that the passive temperature sensing tags can achieve rapid and accurate temperature sensing within the 34–42 °C range. [ABSTRACT FROM AUTHOR]

Taking inspiration from F. Bloch’s seminal work (PRA 7, 2187 (1973)), we investigate the quantum many-body states of superfluid 4He, unveiling a novel characteristic in the system’s energy levels. Below the transition temperature, the thermally active low-energy levels exhibit a distinctive grouping behavior, with each level belonging exclusively to a single group. In a superflow state, the system establishes thermal equilibrium with its surroundings on a group-specific basis. Specifically, the levels within a chosen group, initially populated, undergo thermal redistribution, while the remaining groups of levels stay vacant due to absence of transitions between groups. The macroscopic properties of the system, such as its superflow velocity and thermal energy density, are statistically determined by the thermal distribution of the occupied group. Additionally, we infer that the thermal energy of a superflow has an unusual relationship with flow velocity, such that the larger the flow velocity, the smaller the thermal energy. This relationship is responsible for a range of intriguing phenomena, including the mechano-caloric effect and the fountain effect, which demonstrate a fundamental coupling between the thermal motion and hydrodynamic motion of the system. Furthermore, we present experimental evidence of a self-heating effect in 4He superflows, confirming that a 4He superflow carries significant thermal energy related to its velocity. [ABSTRACT FROM AUTHOR]

Marine collagen is gaining more attraction than terrestrial collagen because it is free of zoonotic disease and religious constrain. In this study, we aimed to investigate and compare the physicochemical properties and functional characteristics of acid‐soluble collagen (ASC‐MF) and pepsin‐soluble collagen (PSC‐MF) extracted from scales of Megalonibea fusca. ASC‐MF and PSC‐MF were evaluated in terms of yield, collagen type, amino acid composition, thermal stability, microstructure, cytotoxicity, and other physicochemical parameters. ASC‐MF and PSC‐MF depicted 1.72 ± 0.2% and 11.72 ± 0.3% of dry weight yields, respectively, and were identified as type I collagen with an intact triple‐helical structure by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE), spectroscopic analysis, and electron microscopy. Additionally, compared with many temperate and tropical species, ASC‐MF and PSC‐MF showed higher thermal stability, with the maximum transition temperature (Tmax) of 53.50°C (ASC‐MF) and 43.16°C (PSC‐MF). CCK‐8 assay showed that ASC‐MF and PSC‐MF have no cytotoxicity in vitro. The determination of blood clotting index values showed that both ASC‐MF and PSC‐MF had good hemostatic ability. In summary, these findings show that PSC‐MF isolated from the scales of M. fusca may be a feasible alternative to terrestrial collagen sources in food and biomedical applications. [ABSTRACT FROM AUTHOR]